聚氨酯用于阻燃和阻尼

Polyurethanes are among the most significant types of polymers in development; these materials are used to produce construction products intended for work in various conditions. Nowadays, it is important to develop methods for fire load reduction by using new kinds of additives or monomers containing elements responsible for materials’ fire resistance. Currently, additive antipyrines or reactive flame retardants can be used during polyurethane material processing. The use of additives usually leads to the migration or volatilization of the additive to the surface of the material, which causes the loss of the resistance and aesthetic values of the product. Reactive flame retardants form compounds containing special functional groups that can be chemically bonded with monomers during polymerization, which can prevent volatilization or migration to the surface of the material. In this study, reactive flame retardants are compared. Their impacts on polyurethane flame retardancy, combustion mechanism, and environment are described.

… flame retardant research. This paper reviews the most recent research advancements in FPUF flame retardant … of FPUF, and introduces the flame retardant mechanism of FPUF from four …

The amplified employment of rigid polyurethane foam (RPUF) has accentuated the importance of its flame-retardant properties in stimulating demand. Thus, a compelling research report is essential to scrutinize the recent progression in the field of the flame retardancy and smoke toxicity reduction of RPUF. This comprehensive analysis delves into the conventional and innovative trends in flame-retardant (FR) systems, comprising reactive-type FRs, additive-type FRs, inorganic nanoparticles, and protective coatings for flame resistance, and summarizes their impacts on the thermal stability, mechanical properties, and smoke toxicity suppression of the resultant foams. Nevertheless, there are still several challenges that require attention, such as the migration of additives, the insufficient interfacial compatibility between flame-retardant polyols or flame retardants and the RPUF matrix, and the complexity of achieving both flame retardancy and mechanical properties simultaneously. Moreover, future research should focus on utilizing functionalized precursors and developing biodegradable RPUF to promote sustainability and to expand the applications of polyurethane foam.

… flame-retardant PUFs as well as various strategies to tackle these challenges and improve the flame retardancy … main part of PU chains can effectively increase the flame retardancy and …

… In this work, a mussel-inspired flame retardant containing a catechol moiety, was … polyurethane foam (FPUF). The influence of the coating time, coating temperature, and flame retardant …

Owing to the superior thermal insulating attributes of rigid polyurethane foam (RPUF) compared to other insulating materials (expanded and extruded polystyrene, mineral wool), it remains the most dominant insulating material and most studied polymer foam. Like other polyurethane foam, RPUF is highly flammable, necessitating the incorporation of flame retardants (FR) during production to lower combustibility, promoting its continuous use as insulation material in construction, transportation, and others. The popular approaches for correcting the high flammability of RPUF are copolymerization and blending (with FR). The second method has proven to be most effective as there are limited trade-offs in RPUF properties. Meanwhile, the high flammability of RPUF is still a significant hindrance in emerging applications (sensors, space travel, and others), and this has continuously inspired research in the flame retardancy of RPUF. In this study, properties, and preparation methods of RPUF are described, factors responsible for the high flammability of PUF are discussed, and flame retardancy of RPUF is thoroughly reviewed. Notably, most FR for RPUF are inorganic nanoparticles, lignin, intumescent FR systems of expandable graphite (EG), ammonium polyphosphate (APP), and hybridized APP or EG with other FR. These could be due to their ease of processing, low cost, and being environmentally benign. Elaborate discussion on RPUF FR mechanisms were also highlighted. Lastly, a summary and future perspectives in fireproofing RPUF are provided, which could inspire the design of new FR for RPUF. Graphical Abstract

Polyurethane (PU) foam is widely used in industrial and civil fields, but it is highly flammable. An eco-friendly flame-retardant coating has been fabricated from sodium alginate (SA) and mica powder, it has been applied to PU foam using a facile direct dip coating method, followed by crosslinking with Ca2+ and modification with polydimethylsiloxane (PDMS), respectively. The original porous network structure is maintained in the coated PU (SMPU) foam with a porosity of 90.51 %, and exhibits good thermal stability, hydrophobicity and excellent flexibility. Moreover, the as-prepared SMPU foam exhibits reduced flammability, e.g., the limiting oxygen index (LOI) for combustion of SMPU foam is 30.5 %, whereas that for unmodified PU foam is 16 %. The SMPU foam also exhibits a self-extinguishing effect without melt dripping and passes UL-94 V-0 rating. A significant reduction in the release of heat as well as total smoke and CO2 formation during combustion was noted using cone calorimetry. These improvements in combustion behavior may be ascribed to a physical barrier formed by non-flammable mica powder, SA and PDMS which displays char forming ability. A facile strategy for improvement of the fire safety of PU foam using a green and efficient flame-retardant coating has been demonstrated.

Rigid polyurethane foam (RPUF) is one of the best thermal insulation materials available, but its flammability makes it a potential fire hazard. Due to its porous nature, the large specific surface area is the key factor for easy ignition and rapid fires spread when exposed to heat sources. The burning process of RPUF mainly takes place on the surface. Therefore, if a flame-retardant coating can be formed on the surface of RPUF, it can effectively reduce or stop the flame propagation on the surface of RPUF, further improving the fire safety. Compared with the bulk flame retardant of RPUF, the flame-retardant coating on its surface has a higher efficiency in improving fire safety. This paper aims to review the preparations, properties, and working mechanisms of RPUF surface flame-retardant systems. Flame-retardant coatings are divided into non-intumescent flame-retardant coatings (NIFRCs) and intumescent flame-retardant coatings (IFRCs), depending on whether the flame-retardant coating expands when heated. After discussion, the development trends for surface flame-retardant systems are considered to be high-performance, biological, biomimetic, multifunctional flame-retardant coatings.

In this work, the coatings used phosphorylated chitosan (PCS) and GP-108 via the dip-coating method presented exceptional flame retardancy and antibacterial properties for flexible …

… the flame retardancy and pyrolysis behavior of BP in oxygen-containing (polyurethane, PU) … gas-phase and the condensed-phase flame retardant effect of BP. Through slow heating and …

Flexible polyurethane foam (FPUF) is extensively applied in multiple applications, including automotive, construction, furniture cushioning, and transportation seating, due to its outstanding mechanical properties, sound absorption, breathable characteristics, and versatility. However, FPUF is highly flammable and releases significant quantities of smoke and harmful gases when burned, which presents considerable safety hazards and has led to extensive research into flame retardant solutions. This review covers the development of both conventional and bio-based flame-retardant agents, including reactive-type and additive-type FRs, and surface coating methods, with a focus on their preparation, characterization methods, and underlying flame retardant mechanisms. Additionally, innovative flame retardant technologies, particularly surface coatings, are discussed in terms of their impact on thermal stability, mechanical performance, and smoke toxicity reduction in the resulting FPUFs. The review also highlights future research priorities and significant challenges, including environmental concerns, cost-effectiveness, and durability. Future research will need to focus on improving flame retardant efficiency while also considering the environmental impact and recyclability of materials, aiming for the green and sustainable development of FPUFs.

A supramolecular self-assembly method was used to prepare melamine cyanurate/α-ZrP nanosheets (MCA@α-ZrP) as a novel hybrid flame retardant for thermoplastic polyurethane (TPU). Microstructure characterization showed a uniform dispersion with strong interfacial strength of the MCA@α-ZrP hybrid within the TPU matrix, leading to simultaneous enhancements in both mechanical and fire-safety properties. The TPU/MCA@α-ZrP nanocomposite exhibited 43.1 and 47.0% increments in tensile strength and fracture energy, respectively. Thanks to the platelike structure of α-ZrP coupled with the dilution effect of MCA (releasing nonflammable gases), the hybrid MCA@α-ZrP reduced the peak heat release rate of TPU by 49.7% in comparison with 15.8 and 35.4% for TPU/MCA and TPU/ α-ZrP composites, respectively. The fire performance index of TPU is significantly promoted by 90% upon adding the MCA@α-ZrP hybrid. Additionally, LOI and UL-94 tests showed high flame-retarding characteristics for the MCA@α-ZrP hybrid. For example, LOI increased from 20.0% for neat TPU to 25.5% for the MCA@α-ZrP hybrid system, and it was rated V-1 from the UL-94 test. Furthermore, the smoke production and pyrolysis products were significantly suppressed by adding the MCA@α-ZrP hybrid into TPU. Interfacial hydrogen bonding, the dilution effect of MCA, forming a "labyrinth" layer, and catalytic action of α-ZrP nanosheets synergistically improved both the mechanical performance and flame retardancy of TPU nanocomposites. This work provides a new example of integrating traditional flame retardants with functional nanosheets to develop polymeric nanocomposites with high mechanical and fire-safety properties.

… analysis, the flame retardant mechanism of the TPU/ … flame retardant role in the condensed phase. This work also provides a green and facile methodology for creating flame retardant …

… ratio and minimal flame-retardant additive required to … the flame retardancy and thermal properties of the composite system. The findings revealed that with just 6 wt.% of flame retardants…

… required flame retardancy, a large number of flame retardants are … To balance the flame retardancy and mechanical … content (20.1 %) for flexible polyurethane foam (FPUF). Notably, …

Thermoplastic polyurethane (TPU) has a wide range of applications in the fields of coatings, cables, garments, automobiles, medicine, and health. However, the flammability of TPU poses a serious threat to life and limits its further development. Significant advancements have been made in the use of nano‐flame retardants in TPU in recent years. Traditional flame retardants usually require high additive amounts and have adverse effects on material properties. In contrast, nano‐flame retardants can significantly improve the fire safety properties of TPU at low additive amounts due to their unique size and surface effects. To the best of our knowledge, there is no comprehensive review of nano‐flame retardants for TPU. This paper provides an overview of the structural characteristics and combustion decomposition of TPU. In addition, this paper provides a comprehensive overview of recent advances in the use of nano‐flame retardants for TPU, including pure nano‐flame retardants, nano‐flame retardants as synergists, modified nanocomposites, and multilayer structures. This study describes the preparation method and flame retardant efficiency of TPU‐based nanocomposites. The focus is on elucidating their structural design and flame retardant mechanism. More importantly, we highlight the current challenges of flame retardant TPU‐based nanocomposites and propose future research directions. This work aims to help researchers quickly understand the latest advances in the field and to inspire the design of novel flame retardants.

… PU applications in various fields. Therefore, the development of environmentally friendly flame-retardant PU is … to synthesize PU modified with three different flame-retardants separately: …

Waterborne polyurethane has drawn extensive attention due to its environmental friendliness and is widely used in many areas. However, it is still a great challenge to synthesize waterborne polyurethanes with flame retardancy and fast room-temperature self-healing ability, along with excellent mechanical performance and emulsion stability due to the mutually contradictory nature of these properties. Herein, waterborne polyurethanes containing organic selenium (SWPU-x) from 0.67 to 3.28 wt % were synthesized, which could simultaneously realize flame retardancy and self-healing ability based on the ability to scavenge active free radicals at high temperature and the dynamic switch of diselenide. All these SWPU-x films self-extinguished within 1 s after the ignition in the vertical combustion tests. The limiting oxygen index of SWPU-4 was improved to 28.5% with excellent UL-94 level (V-0) and self-healing efficiency (91.25%, after being healed in the photoreactor for 30 min at room temperature), together with high mechanical properties (tensile strength was 18.5 MPa and elongation at break was 869.63%), and the total heat release (THR) for SWPU-4 (49.28 MJ/m2) could decrease to 23.80% of the THR for the original waterborne polyurethane WPU (64.67 MJ/m2). This work discovered a new flame-retardant element (organic selenium) and studied its flame-retardant behaviors and self-healing function simultaneously, which would extremely extend the application of waterborne polyurethanes.

… use in damping and vibration isolation. However, an undesirable property of pure polyurethane is … ways to design damping PU materials based on two initial polyurethanes with different …

Excessive plastic deformation may occur at the beam-column joints under seismic action and lead to connection failure, increasing the possibility of collapse of the entire frame structure. In order to improve the seismic performance of assembled steel structure joints, a right-angle viscoelastic joint damper with polyurethane as the core energy dissipation material is proposed in this paper. First, the temperature scanning tests of polyurethane materials were carried out based on the dynamic mechanical analysis method. Second, the dynamic mechanical test and numerical simulation analysis of the designed right-angle viscoelastic damper were performed to reveal the dynamic energy dissipation characteristics of the right-angle damper. Finally, the dynamic time-history damping analysis was performed on the steel frame structure equipped with RVDs. The results show that the TA value of polyurethane material reached its peak at 2.0 Hz, which is the ideal frequency for the material’s damping ability. The right-angle damper made of polyurethane material has a softening nonlinear characteristic, and the peak value of the loss factor was obtained at 2.0 Hz, which is consistent with the results of the dynamic performance of the polyurethane material. The numerical simulation results demonstrate that stress on the steel plates and viscoelastic layers is reasonable. When the excitation level did not exceed 9 mm displacement amplitude, the energy input to the damper was dissipated by polyurethane, and the steel plates never showed plastic deformation. The time-history analysis of the steel structure shows that the dampers designed in this paper have a good control effect on the interstory displacement, acceleration, and interstory shear force of the structure. The research results lay the necessary foundation for the engineering application of polyurethane materials in the field of beam-column joints vibration damping.

… Polyurethane has the characteristics of high damping and high strength, which maybe a … improve the damping properties of concrete. In this paper, eleven groups of polyurethane-based …

… Moreover, the damping factor remains consistently above 0.7 in … damping layer in pipelines. This research demonstrates an outstanding thermoplastic polyurethane damping material, …

Polyurethane is the main matrix material of polymer damping materials, but the damping temperature range is narrow, the effective damping temperature range does not match the working temperature of the material, and the elastic modulus is sensitive to temperature during glass transition, which is not conducive to safe use in a wide temperature range. In this paper, the polyurethane gradient material with the hard segment content continuously changing along the length direction was designed and prepared by the reaction injection method. Dynamic mechanical analysis (DMA) shows that the gradient structure greatly influences the comprehensive damping performance of polyurethane. While maintaining no significant decrease in mechanical properties, the gradient material extends the effective damping temperature range (TR) from 40.7°C (−32.3 ~ 8.4°C) for component A and 66.6°C (59.5 ~ 126.1°C) for component B to 139.5°C (−20.6 ~ 118.9°C). At the same time, the damping peak remains high (0.48), which is close to the higher damping peak of the B component of 0.56. The elastic modulus (E′) decreases slowly with the increase in temperature, which can better ensure the safety of the material.

Granular materials promise opportunities for the development of high-performance, lightweight vibration-damping elements that provide a high level of safety and comfort. Presented here is an investigation of the vibration-damping properties of prestressed granular material. The material studied is thermoplastic polyurethane (TPU) in Shore 90A and 75A hardness grades. A method for preparing and testing the vibration-damping properties of tubular specimens filled with TPU granules was developed. A new combined energy parameter was introduced to evaluate the damping performance and weight-to-stiffness ratio. Experimental results show that the material in granular form provides up to 400% better vibration-damping performance as compared to the bulk material. Such improvement is possible by combining both the effect of the pressure–frequency superposition principle at the molecular scale and the effect of the physical interactions between the granules (force-chain network) at the macro scale. The two effects complement each other, with the first effect predominating at high prestress and the second at low prestress. Conditions can be further improved by varying the material of the granules and applying a lubricant that facilitates the granules to reorganize and reconfigure the force-chain network (flowability).

… the vibration damping coefficient confirmed the possibility of using flexible polyurethane foams of natural origin as an alternative to the previously used vibration damping materials in …

Abstract In this study, using a solution casting process, thermoplastic polyurethane elastomer (TPU) composites containing different contents of lead zirconate titanate (PZT) ferroelectric particles were produced. The damping treatment of composites at high volume of fillers was investigated. SEM micrographs showed that PZT particles had a proper distribution in the PU matrix. Differential scanning calorimetry (DSC) thermograms indicates that melting enthalpy decreases by raising PZT filler content. The results of the dynamic mechanical thermal analysis (DMTA) proved that the magnitude of loss factor (tan δ) strongly depends on PZT content, and it decreased from 0.51 to 0.27 as PZT content increased. The value of E0 increases to 0.32 GPa in the composite reinforced with 50 v% of PZT. The role of PZT on the acoustic behavior of TPU was measured using the acoustic absorption coefficient (a). The results showed that as PZT content increased from 0 to 50%, the acoustic absorption coefficient reached 0.25 at 6000 Hz frequency. The composites of PZT/PU with 0–3 connectivity were poled, and the optimal poling conditions that could be applied without sample breakdown were studied. Moreover, we prepared composites containing 70 vol% PZT particles by modifying the particles. Modification of PZT particles caused a decrease in both d33 and g33 constants of the PZT/PU composites.

… -based materials with room-temperature high-damping property … polyurethane (bio-PU) elastomer with an adjustable damping-temperature range and room-temperature high-damping …

… and damping properties. The damping improvement mechanism of polyurethane cement … In the paper, the effects of PU (0%, 5%, 10%, 20%, 30%, and 40%) and w/c (0.35, 0.45, and …

In this work, polyurethanes (PUT‐X/PUP‐X) with distinct microphase structures were synthesized via a simple two‐step process. While maintaining identical chemical group compositions, the microphase heterogeneity of the polyurethanes was systematically enhanced by regulating the average molecular weight of the polyols. The microstructures of the materials were analyzed and characterized, and their dynamic mechanical properties were investigated, revealing an inverse correlation between the degree of microphase heterogeneity and dynamic mechanical performance. Furthermore, this study supplements the LA/TA (loss area/tanδ area) linear additivity theory in the damping group contribution theory, demonstrating that the damping properties of polyurethane are not solely determined by the type and number of chemical groups but are also significantly influenced by the internal microphase structure‐induced heterogeneity. This research provides a more comprehensive theoretical foundation for the subsequent design and development of high‐damping polyurethane.

In this study, damping coatings were used to dissipate low‐ and medium‐frequency (200–1600 Hz) traffic noise. A waterborne polyurethane/polyacrylate (WPUA) emulsion with superior damping and mechanical properties was prepared by blending polyurethane with commercial waterborne polyacrylate (SETAQUA 6754). The emulsion was combined with sound‐absorbing polyester fibers (PFs) to develop a PF/WPUA damping coating. SETAQUA 6754 improved the loss factor and mechanical properties of the waterborne resin. The composition ratio, molecular chain length, and crosslinking degree improved the damping properties of WPUA by modulating its glass transition temperature, molecular chain friction, hydrogen bonding, and molecular chain free volume. When the thickness of the waterborne damping coating was 1 cm, PF/WPUA reduced the noise by 7 dB at 200 Hz and 23 dB at 1600 Hz, indicating the effectiveness of the PF/WPUA coating in reducing reduce low‐ and medium‐frequency traffic noise.

Vibration and noise-reduction materials are indispensable in various fields. Polyurethane (PU)-based damping materials can dissipate the external mechanical and acoustic energy through molecular chain movements to mitigate the adverse effects of vibrations and noise. In this study, PU-based damping composites were obtained by compositing PU rubber prepared using 3-methyltetrahydrofuran/tetrahydrofuran copolyether glycol, 4,4′-diphenylmethane diisocyanate, and trimethylolpropane monoallyl ether as raw materials with hindered phenol, viz., and 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)proponyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane (AO-80). Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, and tensile tests were conducted to evaluate the properties of the resulting composites. The glass transition temperature of the composite increased from −40 to −23 °C, and the tan δMax of the PU rubber increased by 81%, from 0.86 to 1.56 when 30 phr of AO-80 was added. This study provides a new platform for the design and preparation of damping materials for industrial applications and daily life.

… Polyurethane elastomer has become a current focal point in the field of damping materials due to superior comprehensive properties. However, its effective damping temperature range …

Presently, piezoelectric materials are gradually playing a significant role within composites to improve the damping and vibrational attenuation capacities of host composites. Previous studies paid attention to isolating the mechanical damping contribution and piezoelectric contribution of polymer-based piezoelectric composites (PPCs). However, reports detailing the piezoelectric damping of such materials have not paid sufficient attention to the technologies and methods to improve the piezoelectric damping of PPCs. In this study, we propose novel damping polyurethane (PU)-based piezoelectric composites with carbon-coated piezoelectric fillers (PZT@C/PU) with improved piezoelectric damping ability. The mechanical damping and piezoelectric damping of composites were theoretically decoupled, and we elaborate on the mechanism enhancing piezoelectric damping through the carbon coating strategy by comparing with the composites with nonpiezoelectric fillers. The as-fabricated core-shell structure having an optimized interface exhibits the proposed PZT@C/PU composite pads with relatively prominent damping ability (loss factor tan δmax = 1.0, tan δRT = 0.3), ductility (400.63%), and sound isolating behavior (transmission loss TL > 23 dB). Moreover, the vibration test results of as-fabricated sandwich structural PZT@C/PU composite damping devices exhibit outstanding vibration attenuating behavior (damping ratio ζ = 0.198). The study herein validates that the carbon shell coated on piezoelectric fillers would effectively increase damping performance of PU-based piezoelectric composites by the enhancement of piezoelectric performance caused by carbon coating piezoelectric fillers, which indicates that this material has potential for future applications in the field of vibration and noise reduction, thereby driving forward and expanding the fundamental understanding in the area of PPCs damping and vibration attenuation.

Understanding how dangling fragments of polyurethanes (PU) affect its microphase separation structure and damping properties can provide insights for designing desired materials at the molecular scale. By varying the types of diol extenders (such as 1,2‐ethyleneglycol, 1,2‐propanediol, and 1,2‐butanediol), PU samples with different dangling residues were successfully synthesized. Using atomic force microscopy and small‐angle x‐ray scattering, we confirmed that the introduction of dangling chains disrupts microphase separation and demonstrated a correlation between the degree of suppressed microphase separation and the size of the dangling residues. Fourier transform infrared spectroscopy and molecular dynamics simulations confirmed that dangling chains reduce the hydrogen bonding index while increasing the phase compatibility between soft and hard segments. Differential scanning calorimetry (DSC) measurements revealed an increased glass transition temperature (Tg), indicating hindered movement of backbone segments due to dangling chains. Moreover, lengthening the dangling chains further decreased Tg. Dynamic mechanical analysis (DMA) demonstrated improved damping properties with the introduction of dangling chains, although increasing chain length led to deteriorating damping properties, consistent with observations from DSC. These findings suggest that the variations in macroscopic properties of PU induced by dangling chains are linked to hydrogen bonding interactions and micromorphology at the molecular level.

Vibration and noise severely affect the operation of mechanical equipment and is also detrimental to human health. Therefore, the development of high performance damping materials is crucial. However, current methods to improve damping properties often come at the expense of mechanical properties, resulting in inferior mechanical performance of materials. In order to address the issue of imbalance between damping properties and mechanical properties in polyurethane damping elastomers. In this study, polyester dangling chains containing polar groups are synthesized and introduced into polyurethane. The obtained polyurethane exhibited an effective damping temperature range of 154 °C (−54 °C to 100 °C) and a tensile strength of 15.82 MPa. Furthermore, dynamic mechanical analysis and broadband dielectric relaxation spectroscopy are combined to investigate the influence of polar dangling chains on the structure and properties of polyurethane. The degree of microphase separation increases after the introduction of polar dangling chains, indicating enhances intermolecular interaction forces, facilitating the formation of hydrogen bond between the main chain and dangling chains, thereby increasing molecular chain friction and energy dissipation. This work overcomes the challenge of balancing the damping and mechanical properties of polyurethane, providing a new strategy for designing high performance polyurethane damping elastomers.

… , high-performance polyurethane-based damping composites (… damping characteristics. In addition, the Joule heat was in turn rapidly absorbed by water. Compared to pure polyurethane…

The growing demand for viscoelastic polyurethane foams creates a need for new sustainable raw materials that support cost-effective production while maintaining the desired material performance and fire safety standards. In this regard, our study aimed to develop viscoelastic polyurethane foam composites with reduced flammability and a high proportion of renewable raw materials. To achieve this, blackcurrant pomace, expandable graphite and a third-generation blowing agent were introduced to a viscoelastic polyurethane foam composition containing a reactive flame retardant in the formulation. The effects of the incorporated additives on the foaming process, flammability, chemical structure, cellular structure, thermal properties and physico-mechanical properties of the composites were determined. The results showed that the viscoelastic foam composite containing 30 php of blackcurrant pomace and 15 php of expandable graphite had a pHRRmax 52% lower than that of the reference material. The additional use of a blowing agent enhanced the flame-retardant effect of the materials, resulting in a 67% reduction in pHRRmax of the composite compared to the reference material. Moreover, the developed biocomposites exhibited promising limiting oxygen index values of 26–28%, compared to the 21% shown for the reference sample. Consequently, the best-performing biocomposites achieved the V-0 flammability rating according to the UL-94 standard. This study’s results indicate the composites’ high application potential due to their reduced flammability and the materials’ desirable physical and mechanical properties.

The influence of non-halogenated additive flame retardants, expandable graphite (EG) and ammonium polyphosphate (APP)—as well as a reactive phosphorus-containing polyol, on the flammability, thermal stability, physico-mechanical performance, and morphology of viscoelastic polyurethane foams (VEFs) was investigated. For this purpose, a series of polyurethane foams incorporating both additive and reactive flame retardants was synthesized and analyzed. The incorporation of flame retardants led to a substantial enhancement of fire resistance, as evidenced by an increase in the limiting oxygen index (LOI) to 28–31%, achievement of the UL-94 V0 flammability rating, and a 92% reduction in peak heat release rate (pHRR) compared to the unmodified reference foam. Alterations in mechanical performance were correlated with structural changes both at the microscopic and molecular level, confirmed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

Adhesives are being used ubiquitously, such as automotive, building, electronics, and beyond. Due to the lack of rational design strategies, they have yet to achieve a performance portfolio: mechanically robust, highly adhesive, fire‐retardant, switchable, and sustainable (e.g., biobased, reusable, biodegradable) to ensure their practical applications. Herein, a fire‐retardant phosphorus‐containing pimaric acid bio‐derivative, AD, as functional segments, is rationally engineered to prepare biobased polyurethane (PU) adhesive that realizes such an integrated performance portfolio. Because of dynamic hydrogen‐bonding and π–π stacking of polar AD, the as‐prepared PU adhesive exhibits an ultrahigh adhesion force of 38.8 N cm–1. As‐prepared adhesive can be readily reused benefiting from its good solubility in ethanol and exhibits temperature‐responsive switchable adhesion without degraded adhesion. Also, the adhesive shows intrinsic fire retardance due to its biphasic modes of action. The labile ester bonds in the structure enable the adhesive to completely degrade in the presence of lipase or dilute acid. Further demonstration of its promising applications as an adhesive for nanocomposite heat dissipators shows superior dissipating efficiencies to commercial heat sinks. This work offers a novel design approach for creating next‐generation sustainable high‐performance adhesives with functional integration and circular life cycles, which are anticipated to find extensive real‐world applications.

: Recent advancements in developing tannin-based non-isocyanate polyurethane (NIPU) resins have unlocked new possibilities for sustainable and eco-friendly wood adhesives. Unlike conventional polyurethane, NIPUs eliminate hazardous isocyanates, offering safer alternatives for industrial applications. Tannin, a naturally occurring polyphenolic compound, plays a pivotal role in enhancing these resins’ fire-resistance and super-hydrophobic properties. This review highlights key developments in synthesizing tannin-based NIPU, focusing on various polymerization techniques such as polyaddition, polycondensation, ring-opening polymerization

… type of bio-based polyurethane (PU)/graphene oxide (… PU into IGO containing pendent-NCO groups during curing process for a flexible strain sensor. The resultant composites (IGO-PU) …

First introduced in 1954, polyurethane foams rapidly became popular because of light weight, high chemical stability, and outstanding sound and thermal insulation properties. Currently, polyurethane foam is widely applied in industrial and household products. Despite tremendous progress in the development of various formulations of versatile foams, their use is hindered due to high flammability. Fire retardant additives can be introduced into polyurethane foams to enhance their fireproof properties. Nanoscale materials employed as fire-retardant components of polyurethane foams have the potential to overcome this problem. Here, we review the recent (last 5 years) progress that has been made in polyurethane foam modification using nanomaterials to enhance its flame retardance. Different groups of nanomaterials and approaches for incorporating them into foam structures are covered. Special attention is given to the synergetic effects of nanomaterials with other flame-retardant additives.

Rigid polyurethane foam (RPUF) is widely used as building materials, automotive protective materials, etc. However, its flammability and the environmental impact of traditional flame retardants limit its further development. As a cellulose biomass flame retardant, silk fibroin can effectively reduce environmental impact. The current work used silk fibroin as a modifying material, leveraging its compatibility with the honeycomb structure of the material and its excellent flame retardancy to prepare multifunctional RPUF with superior flame retardancy, thermal stability, and mechanical properties. The material properties were characterized through thermogravimetric experiments and cone calorimeter tests. The results showed that the initial decomposition temperature of the modified RPUF (RPUF‐SF5) decreased by 10.73°C, the heat release rate (HRR) decreased by 45.62 kW/m2, and the smoke density (Ds) decreased by 7.88%, verifying the fire safety of the modified RPUF as a construction engineering material. Additionally, this study constructed a research method combining Abaqus simulation experiments with quasi‐static compression, overcoming the limitations of single evaluation methods, which indicated that RPUF‐SF5 had the highest compressive strength of 0.07 MPa, avoiding the impact of flame retardants on its mechanical property. These results provided new ideas for the research of the multifunctional RPUF.

Rigid polyurethane foam (RPUF) has attracted great attention as an insulation material, but its inherent flammability restricts its practical application. Developing a sustainable fire-retardant strategy that can improve its fire safety is particularly desirable and challenging. Herein, novel fire-retardant hydrogel coatings based on polyvinyl alcohol (PVA) and borax are proposed and applied in RPUF, and the self-healing, recyclability and flame retardant properties of the coatings are investigated. The dynamic and reversible cross-linked networks based on the borate ester bonds and hydrogen bonds endow the hydrogels with excellent repairability, recyclability, and elasticity. Compared with a neat RUPF, the coated RPUF exhibited improved fire-retardant properties without the inherent advantages being influenced and can be reflected by the 8% increase in the limiting oxygen index (LOI), 20% reduction in total heat release (THR), and 25% decrease in total smoke production (TSP) with the coatings, along with a rapid self-quenching behavior. The novel hydrogel coatings provide a new strategy for the development of flame-retardant coatings, demonstrating the potential of the next generation of self-healing hydrogel coatings to reduce the fire risk of the RPUF.

ABSTRACT Polyurethane (PU) composites have emerged as versatile materials with superior mechanical, thermal, electrical, and functional properties due to the incorporation of advanced reinforcements such as graphene, carbon nanotubes (CNTs), metal oxides, and bio-based fillers. This review provides a comparative analysis of these reinforcements, highlighting their effectiveness in enhancing PU properties for diverse industrial applications. Graphene-based additives exhibit the highest improvement in mechanical performance, with tensile strength increasing by up to 320% and modulus by 40%. Multi-walled carbon nanotubes (MWCNTs) enhance electrical conductivity by 70% and improve electromagnetic interference (EMI) shielding effectiveness by 50%, making them superior for electronic applications. In contrast, nano-clays and silica-based fillers significantly improve thermal insulation, reducing thermal conductivity by 40% while also increasing compressive strength and abrasion resistance. Metal oxide nanoparticles, such as boron nitride and molybdenum disulfide, contribute to 30% higher thermal stability, 50% improved flame retardancy, and enhanced corrosion resistance, making them ideal for protective coatings. Bio-based fillers, including cellulose nanofibrils, improve sustainability by increasing tensile strength by 15%, enhancing water resistance, and reducing environmental impact. Hybrid reinforcement strategies integrating multiple fillers demonstrate the highest versatility, achieving balanced mechanical, thermal, and electrical performance. Additionally, recent advancements in dispersion techniques have mitigated agglomeration challenges, ensuring uniform filler distribution and consistent property enhancement. Despite these advancements, scalability remains a key challenge, particularly in maintaining cost-effectiveness while integrating eco-friendly bio-based fillers. Future research should focus on optimizing recyclability and multifunctionality to develop next-generation high-performance PU composites tailored for aerospace, automotive, and biomedical applications. Graphical Abstract

… to polyurethane foams, such as improvements in the thermal, mechanical, fire resistance and … Thus, this article presents a systematic review of graphene-modified polyurethane foam …

… Elastomers with distinctive viscoelastic behavior are widely … In this work, a biobased polyurethane (bio-PU) elastomer … The demand for materials with enhanced fire resistance …

… Obtain malleable PU networks that possess excellent reprocessability and self-healing performance, as well as superior fire resistance. The vanillin-based PU networks show a high T …

… In addition, the MPUF shows good vibration dampening performance with a maximum loss … of flame-retardant, recyclable, bio-based MPUF with good vibration damping properties, thus …

… This flame retardant was then incorporated into a porous polyurethane foam (MPUF) … -damping, fire-retardant, smoke-suppressing, and anti-dripping properties. Due to the intumescent …

… flame retardants or when flame-retardant elements are integrated into the solution, creating a synergistic effect. Jia et al. explored the flame-retardant … as an effective flame retardant. …

… toxic gases in the case of a fire. Thus, the development of RPU with enhanced flame retardancy is required. In this study, a series of flame retardancy evaluation methods are presented, …

To improve the noise reduction and fire resistance of marine coating materials, some fire‐resistant polyurethane damping materials were prepared by varying the ratio of esterified branched polyols (EBP) and the 1,4 butanediol (1,4 BD), the content, and the particle size of the mica filler. The effects of branch chain, mica filler content, and particle size in polyurethane structure on the mechanical, dynamic mechanical properties, and fire resistance of polyurethane and its polymerization process were studied. The experimental results showed that the effective damping temperature range of polyurethane material widened from 42.1 °C to 76.6 °C, and then narrowed to 31.2 °C with the increase in EBP ratio. And the maximum loss factor (tanδmax) of these samples is 0.989. The increase of mica content and the decrease of mica particle size in polyurethane damping materials make the dynamic mechanical properties of polyurethane damping materials present a trend of first improving and then impairing. Moreover, the mechanical properties of polyurethane enhanced with the increase of EBP and weakened with the increase of mica mass fraction. This research is expected to advance the development of marine coatings and address noise reduction and fire protection challenges for marine materials.

Polyurethane (PU) foams are cellular polymeric materials that have attracted much attention across various industries because of their versatile properties and potential for multifunctional applications. PU foams are involved in many innovations, especially in multi-functional and high-performance applications. Special attention is given to developing tailored PU foams for specific application needs. These foams have various applications including flame retardancy, sound absorption, radar absorption, EMI shielding, shape memory, and biomedical applications. The increasing demand for materials that can perform multiple functions while maintaining or enhancing their core properties has made PU foams a focal point of interest for engineers and researchers. This paper examines the challenges faced by the PU foam industry, particularly in developing multifunctional products, as well as the strategies for improving sustainability, such as producing PU foams from renewable resources and recycling existing materials.

… However, enhancing their flame retardancy and damping … In this work, we synthesized a novel reactive flame retardant, 1,4-… high-performance flame-retardant polyurethane elastomers (…

… Polyurethane foams (PUFs) have broad applications in vibrational damping and noise … (D-GO) has been shown to concurrently enhance flame retardancy, smoke suppression, thermal …

We synthesized a novel chain extender (HDF) featuring disulfide and imine bonds and incorporated it into PUE. The PUE cured with HDF exhibits outstanding damping and mechanical properties.

Abstract Cobalt disulphide (CoS2), 3-amino-5-ethoxy-1,2,4-triazole (AET), and graphene oxide, also known as GO, were added to polyurethane (PU) coatings to improve their anticorrosion and fire-retardant properties. To analyze the structural and morphological behaviours of the films of pure CoS2, AET/CoS2, GO/CoS2, and GO/AET-CoS2, SEM/EDX, TEM, TGA, XPS, and XRD techniques were used. The peak heat release rate (PHRR) and total heat release (THR) of polyurethane-graphene oxide/AET-CoS2 were significantly lower than those of polyurethane, with differences of 64.7% and 52.8%, respectively, demonstrating better flame retardancy. The anticorrosive, hydrophobic, and flame-retardant characteristics of the PU-GO/AET-CoS2 nanocomposite were confirmed using mechanical testing and electrochemical methods. Impedance studies confirmed that the corrosion protection performance of PU-GO/AET-CoS2 in seawater was much greater (22,481 kΩ cm2) than that of the plain polymer (157 kΩ cm2). The PU-GO/AET-CoS2 nanocomposite coated AA7039 aluminium alloy had the lowest aluminium ion dissipation as evidenced by SECM investigations. The PU-GO/AET-CoS2 coating had superior hydrophobic properties (WCA: 164°). Therefore, PU-GO/AET-CoS2 could be exploited as a potential material for coatings in industrial processes.

… to the PU matrix improves the PU coating's anticorrosive, hydrophobic, flame retardancy, and … This means that the PU-GO/MMTD-ZrS 2 nanocomposite could be applied in industrial …

… environmentally halogen-free flame retardants (FRs) … flame retardants on cell structure, flammability, thermal properties as well as apparent density, and mechanical property of B-PU…

MXene, a promising two-dimensional nanomaterial, exhibits significant potential across various applications due to its multilayered structure, metal-like conductivity, solution processability, and surface functionalization capabilities. These remarkable properties facilitate the integration of MXenes and MXene-based materials into high-performance polymer composites. Regarding this, a comprehensive and well-structured up-to-date review is essential to provide an in-depth understanding of MXene/thermoplastic polyurethane nanocomposites. This review discusses various synthetic and modification methods of MXenes, current research progress and future potential on MXene/thermoplastic polyurethane nanocomposites, existing knowledge gaps, and further development. The main focus is on discussing strategies for modifying MXene-based compounds and their flame-retardant efficiency, with particular emphasis on understanding their mechanisms within the TPU matrix. Ultimately, this review addresses current challenges and suggests future directions for the practical utilization of these materials.

… flame-retardant performance of polyurethane (PU) foam by using effective flame-retardant … The addition of non-halogen flame retardants (FRs) including aluminum trihydroxide (ATH), …

… Additionally, compared to plain PU, the PU-GO/APMS-MnS 2 shown greater flame retardancy … The anticorrosive, hydrophobic, flame retardancy, and mechanical performance of the PU …

… Consequently, the PU/functionalized NbN/GCN nanocomposite presents itself as a … Flame retardancy tests were conducted to assess the fire-resistant properties of the nanocomposites. …

… The proposed foams exhibit outstanding flame retardancy, superhydrophobicity, … flame retardant show a high flame resistance that can extinguish flame within 2 s after removing a flame …

… and thermal property of PUF/ZnO nanocomposites with and without ATH flame retardant The flame retardancy of the nanocomposite foams in this study was investigated through the …

ABSTRACT Nanocomposites with impermeable two-dimensional materials show promise for metal corrosion protection. A coating matrix incorporating (3-aminopropyl)trimethoxysilane (AMS) functionalized molybdenum nitride (Mo2N) enhances the barrier effect due to its chemical and thermal stability. Further improvement is achieved by adding functionalized Mo2N into graphitic carbon nitride (GCN) within a polyurethane (PU) matrix, enhancing corrosion protection and fire retardancy. Electrochemical techniques evaluated the efficacy of aluminium coated with PU and varying concentrations of functionalized Mo2N/GCN. The resulting PU composite exhibited superior flame retardant capabilities, reducing peak heat release rate (pHRR), total heat release (THR), and total smoke production (TSP) compared to pure PU. Electrochemical impedance spectroscopy (EIS) showed enhanced coating resistance (5.55 × 101 1 Ω.cm2) even after 500 hours of exposure. Additionally, the composite displayed exceptional water repellency with a water contact angle (WCA) of 156° and commendable mechanical properties, including an adhesive strength of 19.2 MPa within the PU substrate. This multifunctional PU composite, incorporating functionalized Mo2N/GCN, presents a promising option for automotive coatings, offering corrosion protection, flame retardancy, water repellency, and mechanical robustness, thus enhancing durability and performance in harsh conditions.

… GO/DAT-CeS 2 in the PU matrix produced the best coating … plain PU, the PU-GO/DAT-CeS 2 showed greater flame retardancy … , flame retardancy, and mechanical performance of the PU …

… flame retardant polyurethane/SiO 2 composite foams were designed. Firstly, the vanillin based flame … Subsequently, a series of flame-retardant polyurethane/SiO 2 composite foams (…

… strength and hardness within the PU substrate, enabling the coating to … fire resistance, water repellency, and mechanical durability. Thus, the PU/functionalized HfN/GCN nanocomposite …

Nanocomposites incorporating impermeable two-dimensional materials offer promising solutions for safeguarding metals against corrosion. Here, we explore the integration of [3-(2-…

… with polyurethane, alongside varying concentrations of functionalized MoN/GCN, was assessed. The resulting PU composite exhibited superior flame-retardant … to pure PU formulations. …

… loss factor properties per se do not mimic the real time conditions of vibration damping treatment, wherein the viscoelastic material is used as a free layer (FLD) or a constrained layer …

… 17 researched the multiphase viscoelastic hysteretic behavior of an interpenetrating polymer network of styrene butadiene rubber-poly applied in a vibrational damper. Bao et al. …

… TPU in the design of adaptive vibration isolation structures. … , which is critical for vibration isolation systems that require a … Work [11], devoted to PLA, also notes that the viscoelastic …

… for polyurethane foam, asphaltic membranes, constrained layer dampers, and other viscoelastic … more often in dampening applications to combine vibration reduction with increased …

… technique for utilizing viscoelastic damping materials in the passive control of structural vibrations. In this study, CLD is implemented by sandwiching a polyurethane rubber layer …

Porous polymer composites (PPC) have developed rapidly recently, which are widely used in various industrial fields. Viscoelastic damping is an important behavior of porous polymer composites, and it can determine the sound absorption for noise reduction applications. This review has mainly covered the viscoelastic damping and sound absorption of porous polymer composites. Different fabrication approaches of porous polymer composites are gathered. The mechanism of viscoelastic damping behavior is described, and also the sound absorption properties. Followed by the introduction of enhanced sound absorption of viscoelastic damping porous polymer composites, including the incorporation of fillers, microstructures modification, combination with nanofibrous materials, and multilayer configuration, etc. The incorporated fillers can effectively adjust the interfacial area in composites, and obtain desired bonding conditions. Microstructures modification is an effective tool to improve the morphologies of both polymer matrix and fillers, which can be achieved by chemical treatment and surface coating. The combination with lightweight nanofibrous layer can increase the low frequency absorption. The configuration of multilayer composites can improve both acoustical and mechanical properties for engineering applications. It is hoped that this comprehensive review is benefit for the promising development of porous polymer composites in related fields.

In this article, an attempt was made to model the body of a person moving in a passive manner (movement forced by another person) in a wheelchair. For this purpose, the Wan–Schimmels model was modified by 4 DOF, supplementing it with the weight of the wheelchair and a polyurethane cushion. The study was designed to test the effectiveness of utilizing a polyurethane cushion to reduce the whole-body vibration acting on a person while moving in a wheelchair. The study used a rheological model of polyurethane (PU) foam with concentrated parameters. Harmonic and random vibration analysis was carried out for this model. At the same time, the model with 5 DOF seems to be sufficient to describe vibrations transmitted to wheelchair users. The model presented in this paper can become a tool for future analysis of vibrations of people of different weights, moving passively on various types of wheelchairs on surfaces whose irregularities can be given by an appropriate form of kinematic excitation. The approach used in this study is likely to be useful in selecting a wheelchair and seat cushion so as to counteract and minimize vibrations perceived by humans.

… coordination with EG system showed better flame retardancy effect than the foam with only … synergy in RPUF. Zhang et al. incorporated PCP and GF in polyurethane foam to fabricate fire…

… required to achieve the desired flame-retardant effect, with a … (DMMP) as a synergistic flame retardant to foam system. The … enhance the flame retardancy of polyurethane foams at a …

Waterborne polyurethanes (WPUs) have attracted great interest owing to their environmentally friendly properties, and are wildly applied in production and daily life. However, waterborne polyurethanes are flammable. Up to now, the challenge remains to prepare WPUs with excellent flame resistance, high emulsion stability, and outstanding mechanical properties. Herein, a novel flame-retardant additive, 2-hydroxyethan-1-aminium (2-(1H-benzo[d]imidazol-2-yl)ethyl)(phenyl)phosphinate (BIEP-ETA) has been synthesized and applied to improve the flame resistance of WPUs, which has both phosphorus nitrogen synergistic effect and the ability to form hydrogen bonds with WPUs. The WPU blends (WPU/FRs) exhibited a positive fire-retardant effect in both the vapor and condensed phases, with significantly improved self-extinguishing performance and reduced heat release value. Interestingly, thanks to the good compatibility between BIEP-ETA and WPUs, WPU/FRs not only have higher emulsion stability, but also have better mechanical properties with synchronously improved tensile strength and toughness. Moreover, WPU/FRs also exhibit excellent potential as a corrosion-resistant coating.

… balanced flame retardancy in flexible polyurethane foam (… We analyzed the flame-retardant mechanism of different … study provides ideas for the design of FPUF flame retardants. …

… a good synergistic flame retardancy on polyurethane composites and can reduce fire risk. … Whereas, there are few reports on the combination of synergistic flame retardancy for the …

… -nitrogen flame retardant (ZrMP… flame retardancy of rigid polyurethane foam/expandable graphite (RPUF/EG) composites. The synergistic effect of ZrMP and EG on the flame retardancy …

… gases during combustion, synergistically enhancing the gas-phase flame retardancy of CS-BP … the flame retardancy efficiency and broaden the application of BP-based flame retardants. …

… Rigid polyurethane foam (RPUF) is widely used for building … Researchers have explored various additive flame retardants … flame-retardant RPUF. These polyols were used in a reactive …

… polyurethane foams (RPUFs) with excellent flame retardancy and mechanical properties, this study incorporates the ternary flame-retardant … improves the flame retardancy of the PAPP/…

… flame-retardant polymer composites is crucial for enhancing safety in new energy vehicles. Here, we prepared a composite material with excellent flame retardant … polyurethane (TPU) …

… Therefore, it can be expected that GO-based IFR play a promoting role in flame retardancy. However, the application of three synergistic flame retardants (APP-PBA-GO) in TPU …

Water polyurethane (WPU) with flame retardant and hydrophobic properties was synthesized by in situ polymerization using 9,10-dihydro-9-oxa-10-[N, N-bis-(2- hydroxyethyl-amino-methyl)]-10-phosphaphenanthrene-10-oxide (DOPO-DAM) as flame retardant modifying agent, hydroxyl-terminated polydimethylsiloxane (PDMS) as hydrophobic modifying agent. FT-IR and TEM characterized the chemical structure and morphology of modified WPU. The effects of DOPO-DAM and PDMS dosage on the performance of modified WPU were investigated. The tensile strength for the modified WPU films first increased and then decreased with increasing of DOPO-DAM dosage. Incorporating DOPO-DAM and PDMS into WPU significantly enhanced flame retardancy, as evidenced by the reduction in peak heat release rate, total heat release rate, total smoke production, effective heat of combustion, and carbon dioxide production rate. The scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy confirmed that the good flame retardancy of modified WPU was due to the synergistic effect of P, N and Si elements. Afterward, modified WPU as a finishing agent was coated on polyester fabric. The experimental results of limiting oxygen index (LOI) and the vertical burning test indicated that when the dosage of DOPO-DAM was 6 wt% in modified WPU, after-flame time, after-glow time, damage length and LOI value of the coated polyester fabric were 7.0 s, 0.0 s, 8.5 cm and 26.2%, respectively. In addition, with the increase of PDMS dosage in modified WPU, the water contact angle of the coated fabrics showed an upward trend and remained stable. The addition of PDMS not only improved the flame retardancy of the coated fabric but also had a good effect on hydrophobicity.

Flexible polyurethane foams (FPUF) with superior flame retardancy, smoke suppression, and high resilience remain a significant challenge, particularly in achieving a limiting oxygen …

Abstract: Polyurethane (PU) coatings are widely utilized in fields such as construction, electronics, transportation, and aerospace due to their excellent mechanical properties, resistance to chemical corrosion, and tunable molecular structure....

… , this research introduced a novel flame retardant, DOPO-AZ, … This study successfully enhanced flame retardancy while … The synergistic flame-retardant mechanisms of the RPUF/…

… These fillers are further utilized as flame retardants for TPU, with composites containing 6.0 … in enhancing the flame retardancy of TPU. Due to the excellent flame retardant and thermal …

… flame retardants usually compromise the mechanical integrity of thermoplastic polyurethanes (… a purely gas-phase flame retardant mechanism, and a gas-phase flame retardant, CCu@B…

… Mechanical properties test showed that thermoset elastomer S0 gives higher … loss modulus and loss factor, while thermoset elastomer S4 present higher loss modulus and loss factor …

… polyurethane was employed as the reinforcement elements. As a result, an entangled metallic wire material-polyurethane … On top of that, the mechanical properties (loss factor, energy …

… high-toughness elastic polyurethane (PU) grouting material … The stiffness damage, loss factor, cumulative strain, and strain … and fatigue durability evaluation of PU grouting materials. …

… The stiffness damage and loss factor always varied at a lower … factor affecting the compression fatigue performance of PU … stress level and fatigue life of PU grouting materials. Some …

… polyurethane chains to form a network structure named CNTs-PDA-PU, which improved the ability of polyurethane … significantly enhanced the mechanical and damping properties of …

… rigid PU. As a result of the current study, TC of rigid PU is found doubly enhanced compared to flexible PU … Storage modulus and mechanical loss factor from DMA of: (A) flexible PU with …

… This paper aims to improve the flame-retardant property of asphalt by modifying asphalt with … -friendly flame retardants, and polyurethane (PU) was used together with flame retardants. …

… pad and the polyurethane foam board were tested and analyzed under different loading … rubber damping pad and polyurethane foam board were used as elastic damping materials to …

This study investigates the dynamic stiffness and damping characteristics of three polyurethane materials—PM, PS, and PST—using a comprehensive vibroacoustic testing approach. The aim is to examine material parameters such as dynamic stiffness, Young’s modulus, critical damping factor, and the influence of sample irregularities on the accuracy of measurements. The study employs both experimental testing, in which cuboidal and cylindrical polyurethane samples were subjected to sinusoidal excitation, and finite element modeling (FEM) to simulate the test conditions in sample without irregularities. Results indicate that sample contact surface irregularities (even as low as ~0.04 mm) significantly impact the measured dynamic stiffness, with the effect intensifying for materials with higher Young’s modulus values (above 5 MPa). Furthermore, cylindrical samples demonstrated more stable and repeatable measurements compared to cuboidal samples, where surface irregularities were tested in a more controlled environment. The findings underscore the need to consider sample geometry and irregularities in dynamic stiffness assessments to ensure better material evaluations. This work contributes valuable insights for the accurate modeling and testing of materials used in vibration isolation and sound insulation contexts.

This study explores the impact of ageing factors – i.e., perspiration, disinfection procedures and ultraviolet radiation – on the structural and performance characteristics of novel viscoelastic polyurethane foams specifically developed for use in seals for respiratory protective devices (RPDs). The investigation includes an analysis of resilience, compression set and recovery time to ascertain the influence of the chosen factors on the foam’s mechanical properties. Furthermore, an in-depth exploration of the foams’ thermal properties and chemical structure was carried out using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR), respectively. The influence of the ageing factors on the foams’ microstructure was scrutinized via scanning electron microscopy (SEM), supplemented by assessments of colour change and contact angle alterations. The experimental results were contextualized within the existing literature, with particular attention to the desired attributes of RPD seals composed of these newly engineered materials. Recommendations for use were then formulated.

Rigid polyurethane foams (RPUFs) were synthesized using exclusively lignin-based polyol (LBP) obtained via the oxyalkylation of kraft lignin with propylene carbonate (PC). Using the design of experiments methodology combined with statistical analysis, the formulations were optimized to obtain a bio-based RPUF with low thermal conductivity and low apparent density to be used as a lightweight insulating material. The thermo-mechanical properties of the ensuing foams were compared with those of a commercial RPUF and a RPUF (RPUF-conv) produced using a conventional polyol. The bio-based RPUF obtained using the optimized formulation exhibited low thermal conductivity (0.0289 W/m·K), low density (33.2 kg/m3), and reasonable cell morphology. Although the bio-based RPUF has slightly lower thermo-oxidative stability and mechanical properties than RPUF-conv, it is still suitable for thermal insulation applications. In addition, the fire resistance of this bio-based foam has been improved, with its average heat release rate (HRR) reduced by 18.5% and its burn time extended by 25% compared to RPUF-conv. Overall, this bio-based RPUF has shown potential to replace petroleum-based RPUF as an insulating material. This is the first report regarding the use of 100% unpurified LBP obtained via the oxyalkylation of LignoBoost kraft lignin in the production of RPUFs.

… a gas pycnometer), thermal conductivity, fire resistance, and morphology (observed through … demonstrated outstanding fire resistance performance, reducing the burn length by 127%. …

The increasing demand for sustainable construction materials has driven interest in utilizing waste biomass within polymer composites. Rigid polyurethane foams, widely valued for thermal insulation, exhibit a significant flammability issue. This study investigates the impact of incorporating various waste biomass materials, including brewers’ spent grain, coffee grounds, and soybean husk and their combustion ashes on the selected properties of rigid polyurethane foams. The primary objective is to assess the potential of these eco-friendly additives as replacements for traditional raw materials, aiming to enhance fire resistance and thermal stability and thereby promoting circular economy principles in the construction sector. Composite foam samples were fabricated using a mixing and casting technique, incorporating 5% wt. of fillers into the polymer matrix. Thermal stability and flammability were evaluated using cone calorimetry and thermogravimetric analysis. The findings indicated that while biomass inclusion did not significantly improve char formation, the addition of ash substantially increased char yield, a critical factor in fire suppression. Although biomass and ash may influence flammability, they do not inherently bolster the intrinsic thermal stability of the polyurethane matrix itself.

… crosslinked synthesis method for polyurethane (PU)-modified … The covalent bonds in PU-modified system provided … thermal analysis confirmed successful PU formation, and identified …

The advancement of electric vehicles necessitates a rigorous focus on passenger cabin safety, particularly concerning the severe thermal hazard of a lithium-ion battery thermal runaway. Unlike internal combustion engine vehicles, electric vehicles require interior materials that provide superior thermal resistance to slow heat propagation, delay autoignition, and minimize smoke and toxic gas emissions, thereby securing a survivable evacuation window. This paper examines the application of the lumped-capacitance thermal model and the derived thermal time constant (τ) as a foundational framework for evaluating and selecting cabin materials. This approach enables a quantitative, physics-based ranking of materials—including seat composites, sound-deadening layers, electrical insulation, and carpet assemblies—based on their intrinsic ability to delay their own temperature rise under transient heat flux. By integrating materials with a high τ and elevated critical failure temperatures, this study proposes a performance-based material selection strategy. This strategy is critical for extending the safe egress period mandated by standards such as UN ECE R.100 and GB 38031-2020 and is increasingly vital as safety benchmarks evolve toward longer durations. The synthesis of high-inertia materials with traditional fire-resistant insulation provides a multi-layered defense, enhancing passenger protection by functionally delaying the progression of heat, fire, and hazardous emissions into the occupied cabin space.

The textile industries need an alternative to cotton since its supply is unable to keep up with the growing global demand. The ramie (Boehmeria nivea (L.) Gaudich) fiber has a lot of potential as a renewable raw material but has low fire-resistance, which should be improved. In this work, the objectives were to investigate the characteristics of lignin derived from black liquor of kraft pulping, as well as the properties of the developed lignin-based non-isocyanate-polyurethane (L-NIPU), and to analyze ramie fiber before and after impregnation with L-NIPU. Two different formulations of L-NIPU were impregnated into ramie fiber for 30, 60, and 90 min at 25 × 2 °C under 50 kPa. The calculation of the Weight Percent Gain (WPG), Fourier Transform Infrared Spectrometer (FTIR), Rotational Rheometer, Dynamic Mechanical Analyzer (DMA), Pyrolysis Gas Chromatography Mass Spectrometer (Py–GCMS), Universal Testing Machine (UTM), and hydrolysis test were used to evaluate the properties of ramie fibers. The result showed that ramie fiber impregnated with L-NIPU produced higher mechanical property values and WPG than non-impregnated ramie fiber. There is a tendency that the longer impregnation time results in better WPG values, FTIR intensity of the urethane group, thermomechanical properties, crystallinity, and mechanical properties of ramie fiber. However, the use of DMC and HMT cannot replace the role of isocyanates in the synthesis of L-NIPU because it produces lower heat resistance than ramie impregnated using pMDI. Based on the results obtained, the impregnation of ramie fiber with L-NIPU represents a promising approach to increase its wider industrial application as a functional material.

A shaking table model test of the tunnel was carried out to compare the damping effects of polyurethane foam aluminum(AF/PU) and sponge rubber. The test shows that the damping effect of polyurethane foam aluminum is better, and the dynamic earth pressure and strain values of each measuring point of the tunnel lining are relatively smaller. The ANSYS software was used for the ground motion simulation. The first principal stress and first principal strain of the lining were compared and analysed between the two types of damping layers. It was found that the damping effect of AF/PU was better, which is consistent with the test results. The damping effects of AF/PU with thicknesses of 10, 20, and 30 cm were 22.3%, 29.03%, and 31.41%, respectively. The damping effect increases with an increase in thickness, but the growth rate slows.

Improvements in passenger compartment comfort continue to be one of the key needs of the global transportation industry. Since their introduction more than 40 years ago, flexible molded polyurethane foams have successfully contributed to the comfort provided by all forms of transportation seating. Initially required to provide just a wide range of load bearing, seating foams are now being designed for longer service life and better vibration damping and are considered to be a functional part of the overall acoustical package. New performance requirements are being placed on the NVH grade of foams and all interior components of passenger compartments must contribute to a reduction in odor and emissions. To address the ongoing and newer challenges, The Dow Chemical Company has developed several new chemical technologies that will be detailed in this paper. Specific data will be presented to illustrate new foam chemistries that offer low emissions, reduced density, improved vibration management, noise abatement, durability and processing. Attention will be focused on how the choice of polyurethane raw materials impacts foam resilience, mechanical damping and resonance as well as acoustic absorption and noise transmission. The results presented in this paper will help foam producers, seat assemblers, acoustic part manufacturers and OEM interior designers in their efforts to further improve the comfort performance of transportation systems based on flexible molded polyurethane foams.

… foaming method. It was modified by the synergistic flame retardancy of two flame retardants: … Meanwhile, the char residue of RIBPIF composites with flame retardants after pyrolysis are …

Developing flame-retarded styrene-acrylic emulsion (SAE) based damping composites is a challenging task because of their very high flammability. A promising approach is the synergistic combination of expandable graphite (EG) and ammonium polyphosphate (APP). In this study, the surface modification of APP was modified by commercial titanate coupling agent ndz-201 through ball milling, and the SAE-based composite material was prepared with SAE and different ratios of modified ammonium polyphosphate (MAPP) and EG. The surface of MAPP was successfully chemically modified by NDZ-201 through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), Energy Dispersion Spectroscopy (EDS), and contact angle. The effects of different ratios of MAPP and EG on the dynamic and static mechanical properties and flame retardancy of composite materials were explored. The results showed that when MAPP:EG = 1:4, the limiting oxygen index (LOI) of the composite material was 52.5%, and the vertical burning test (UL-94) was at the V0 level. Its LOI increased by 141.9% compared to the composite materials without flame retardant. The optimized formulation of MAPP and EG in SAE-based damping composite materials showed a significant synergistic effect on the flame retardancy of the composite material.

The necessity of developing a green, circular, and sustainable process to produce high bio-content building materials has directed current research trends. In this paper, we introduce a novel high bio-content-based polyurethane (BPU) nanocomposite foam that is prepared using 100 % bio-polyol and nanocellulose fiber (CNF). Both the bio-polyol and CNF are obtained from bamboo biomass to limit the environmental footprint of petroleum-derived materials. In addition, environmentally-friendly non-halogen flame retardants (FRs) are incorporated into BPU nanocomposite to enhance fire safety, mitigate fire risks, and advance the development of fire-resistant insulation materials and construction technologies. The BPU and BPUC5 nanocomposite foams completely burnt to the holder clamp with a low LOI value and did not pass the UL94 HB standard. With the loading of FR, the BPUC5 nanocomposite foam reached V-0 rating and the LOI value significantly increased up to 21-42 %. The cone calorimeter results showed that the peak heat release rate of BPUC5/FR nanocomposite foams notably decreases by 30.3-42.3 %. These foam materials present a significant potential in thermal insulation applications for the field of biobased building materials for a sustainable future with low carbon emissions and circular economy. In addition, their ultra-lightness is a major advantage in comparison to other bio-insulating materials and PU foams.

Abstract With the increasing use of additive manufacturing (AM) in diverse fields, printed structures are inevitably exposed to vibrations, which can result in fracture, fatigue, and noise. Present study aims to enhance the damping characteristics of the final part by incorporating viscoelastic materials into the primary structure using multi-material AM. The effects of process parameters on the vibration damping characteristics of printed viscoelastic structures were investigated through modal analysis and design of experiments. Results show that higher nozzle temperature, smaller layer height, lower deposition speed and smaller raster angle contribute to higher resonant frequencies and loss factors of the final parts.

… Several viscoelastic damping materials are commonly used in vibration isolation systems, mounted with organosilicon rubber and nitrile rubber (NBR) being widely employed. Other …

Viscoelastic suspension systems serve as components essential for enhancing ride comfort and structural reliability in tracked bulldozers. However, traditional suspension-damping structures often exhibit high-stiffness and reduced-damping characteristics under low-frequency excitations, limiting their adaptability in complex off-road conditions. This limitation adversely affects the operational safety and comfort of tracked bulldozers, particularly in extreme terrains. This study employs an elastic modulus gradient design, combined with the hysteretic properties of viscoelastic materials, aiming to develop five rubber materials with varying elastic moduli and constitutive parameters for damping-layer applications. Through parametric modeling and finite-element simulations, we systematically analyzed both static and dynamic performance across these five configurations while investigating how damping-layer elastic modulus variations influence dynamic vibration-damping characteristics. The results demonstrate that the S-NR3-NR3-S configuration exhibits superior dynamic vibration-damping performance. Further analysis focused on this optimal configuration’s stiffness characteristics and energy dissipation capacity under different harmonic excitations and maximum compression displacements. Finally, practical validation was conducted through static and dynamic performance testing of physical prototypes using a universal testing machine and electro-hydraulic servo-controlled instrumentation, based on operational conditions of high-power tracked bulldozers. The presented findings and methodologies establish a theoretical foundation for optimizing ride comfort in construction vehicles, demonstrating significant practical applicability and engineering value.

To achieve high damping in constrained (PCLD) layer damping, a novel 1-3 viscoelastic composite material (VECM) has been developed. This new composite replaces the traditional monolithic viscoelastic material (VEM) in the construction of the Composite Constrained Layer Damping (CCLD) layer. Viscoelastic materials are commonly used for passive vibration control for the different structural elements through constrained layer damping (CLD) treatment. These structural elements have wide applications in the automobile and aerospace industries. The viscoelastic materials have energy dissipation characteristics which are useful in structural vibration suppression. This viscoelastic material is used in the layer form for passive constrained layer damping (CLD) treatment for the thin-walled flexible structure. The innovative 1-3 VECM layer significantly enhances damping performance. The 1-3 VECM is fabricated with the combination of three layers that is one layer of 2-2 Viscoelastic composite (2-2 VEC) and two layers of viscoelastic materials. This composite layer is utilized in place of the conventional monolithic viscoelastic layer in UCLD and PCLD treatments for structural vibration control. The damping effectiveness of the new 1-3 VEC layer was evaluated through free-vibration testing of a cantilever beam, where the damping layer was affixed between the substrate beam and the thin constraining layer. Experimental results showed a substantial improvement in damping effectiveness with the 1-3 VECM layer when compared to the traditional monolithic viscoelastic layer. This study successfully presents the development of a new CCLD damping layer based on the 1-3 viscoelastic composite (1-3 VEC), highlighting its superior performance in vibration attenuation.

… temperature characterized the mechanical properties of these … observed between the density of polyurethane (PU) foam and the … This paper assesses the capacity of polyurethane to …

The chemical structure, polymer mobility and mechanical properties are studied for a cross-linked amorphous poly(ether urethane) (PU) from glass transition to rubber elasticity for juvenile dry samples and for water-saturated states after exposure to humid air (r.h. = 29, 67, 95, 100%) at 60∘C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$60~^\circ \hbox {C}$$\end{document} during 1 y of ageing. For saturated samples, network chain cleavage is the chemical ageing mechanism, but it is too weak and slow to affect on the physical properties significantly within 1 y. Water acts primarily in a physical manner. Within 1 d, H2O\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {H}_{{2}}\hbox {O}$$\end{document} molecules replace part of the weak urethane H-bonds by H2O\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {H}_{{2}}\hbox {O}$$\end{document}–urethane H-bonds and reduce all other physical interactions between network chains by solvating hydrophilic segments. Thus, the cooperative polymer mobility strongly amplifies: The gain of specific conformational entropy doubles across the caloric glass transition, which shifts by −17 K. A H2O\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {H}_{{2}}\hbox {O}$$\end{document} concentration of only cH2O≈(0.4…0.5)cH2O,max\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {c}_{{\mathrm{H}_2\mathrm{O}}}~\approx ~(0.4~\ldots ~0.5)~\hbox {c}_{\mathrm{\mathrm{H}_2\mathrm{O},max}}$$\end{document} suffices for the major part of these fast rearrangements. Some part of the water slowly forms (during 3–4 months) a finely dispersed water-rich mixed phase with the PU chains. Except the new phase, these molecular processes of physical ageing strongly affect the mechanical properties at damage-free deformation. For dry PU in the glass transition, the shear modulus, μrelaxed\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mu _{\mathrm{relaxed}}$$\end{document}(T), after viscoelastic stress relaxation only depends on the deformation-induced entropy change—like in the rubber elastic state. Within one month, water drastically decreases the viscoelastic response, as expected for plasticisation. However, μrelaxed\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mu _{\mathrm{relaxed}}$$\end{document}(T) slightly grows in wet PU. H2O\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {H}_{{2}}\hbox {O}$$\end{document} molecules cause these opposite trends by boosting the cooperative mobility (i.e. extension of the accessible conformational space and entropy by reduction in energy barriers) and by occupation of free volume compartments. Water quickly reduces the fracture parameters by about 50%. We explain that embrittlement by the H2O\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {H}_{{2}}\hbox {O}$$\end{document}-induced facilitation of cooperative network chain motions, which let fracture proceed with less energy. In summary, our findings provide a detailed conception of the molecular effects the H2O\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {H}_{2}\hbox {O}$$\end{document} molecules have on the PU network, and they explain the consequences for the mechanical properties.

Polymers are widely used in bearing applications. In the case of water-lubricated stern tube bearings, thermoplastic polyurethane (TPU)-based composites are used due to their excellent wear resistance, corrosion resistance, and tunable mechanical properties. Their tribological performance, however, depends on operating conditions. In this work, TPU was blended with carbon fiber, graphene platelet, and ultra-high molecular weight polyethylene (UHMWPE). Friction tests of TPU based-composites against copper countersurface were carried out in water to mimic the actual operating conditions of the bearing. Most of the resulting contacts were in the boundary lubrication regime, in which friction was attributed to both contact mechanics of asperities as well as water lubrication. Our results show that the viscoelasticity of TPU has a considerable impact on its tribological performance. Water lubrication at 50 °C promotes the softening of polymer surface material during sliding, resulting in higher fluctuation in the coefficient of friction and wear loss. This is attributed to the reduced thermomechanical properties. In addition, Schallamach waviness is observed on worn surface. The tribological properties of TPU are significantly improved by the inclusion of carbon fiber, graphene platelet, and UHMWPE. The formation of graphene transfer-layers and UHMWPE transfer film reduces friction and wear loss, while the inclusion of carbon fiber enhances wear resistance due to improved mechanical properties and load bearing capacity.

… These materials must demonstrate mechanical durability and resistance to environmental factors such as moisture and sweat. Herein, we present a polyurethane elastomer (HTPB-PU) …

… The storage modulus is consistent with the loss factor (Figure 3b). However, when the D–A bond was excessive, the hydrogen bond interaction was weak, resulting in a decrease in the …

… The modal loss factors (MLFs) and mean square velocity (MSV) are calculated to estimate the damping performance. The results show that the proposed NS-ABH beam can achieve …

As flexible sensors are soft and prone to damage in practical applications, stretchable conductors with self-healing capacity can extend their service life. However, existing vat …

… mechanical properties rigid polyurethane foams (RPUFs) play an irreplaceable role in aerospace, construction and transportation fields. Microstructure is an important factor … mechanical …

High‐intensity exercise is prone to cause damage to articular cartilage and ligament tears. The existing polyurethane elastomers still face challenges such as poor mechanical strength and insufficient biocompatibility in biomedical load‐bearing materials, which hinders their clinical application. Herein, a strategy based on rigid‐flexible hybrid soft segment supramolecular cross‐linking is proposed to prepare ultra strong and tough bio‐based polyurethane elastomers (BPUs). Rigid polylactic acid polyol (PLA) and flexible poly(1,3‐propanepolyol) polyol (PO3G) are used as the hybrid soft segment. Among them, the crystalline region of PLA enhanced the mechanical strength of the elastomer, and the conformational entropy buffering effect of flexible PO3G reduced the phase interface energy, promoting the spatial uniformity of the microphase separation structure of the elastomer. Meanwhile, a supramolecular hydrogen bond dynamic network is introduced to achieve efficient energy dissipation under stress induction. The developed BPUs has excellent mechanical properties (tensile strength: 82.29 MPa, elongation at break: 2128%, toughness: 993.08 MJ m−3) and biocompatibility. In addition, BPUs are processed into artificial ligaments through 3D printing technology, which have stable mechanical properties and fatigue resistance in a liquid environment. Therefore, this high‐performance sustainable elastomer has great application potential in the field of biomedical load‐bearing (e.g., tendons and ligaments).

The microphase separation behavior of polyurethane (PU) strongly affects its mechanical, thermal, electrical, and other functional properties. Adding fillers to change the degree of microphase separation (DPS) in PU is a convenient and efficient method. Although many scholars have tried to regulate the microphase separation of PU by adding fillers, there are still many controversies about the effect. In this review, we classify commonly used fillers into three categories according to their morphology: spherical fillers, fibrous fillers, and layered fillers, and summarize their effects on the microphase separation behavior of PU. We explore the similarities and differences in the mechanisms by which different fillers affect the microphase separation of PU, and find that the polarity, morphology, size of fillers, and preparation method have a significant impact on the degree of microphase separation in PU. The impact of microphase separation on the mechanical properties of PU has also been summarized to illustrate their close relationship. We hope that these summaries will provide some guidance for the development of new high‐strength and multifunctional PU composites. Summarized recent research progress on effect of common fillers on DPS of PU. Common fillers are classified into three categories based on their morphology. Common laws of the fillers impact on the DPS are classified and discussed. The close relationship between DPS and mechanical properties is reviewed. Provided information for high‐strength and multifunctional PU development.

… polyurethane mortar has excellent mechanical properties. The aim of this study is to explore the mechanical properties and microstructure of the interface between polyurethane mortar …