Synergistic Enhancement Of Impact Resistance Of Polyurethane Elastomers By Ionic Liquid/inorganic Nanoparticles

Compared with traditional metal or inorganic non-metal materials,polyurethane elastomer（PUE）has been widely applied in the field of impact protection due to its light-weight,excellent impact resistance,and good deformation recovery.However,PUE materials also have problems such as cracking and irreversible deformation in a high-speed impact environment.The nanoscale interface between inorganic nanoparticles and the PUE matrix is constructed by ionic liquid as a gradient-interphase,which can effectively solve the problem of weak interface binding force between the two phases and improve the impact resistance of materials.This paper developed a new class of PUE-based nanocomposites with excellent impact resistance and good deformation recovery based on the synergistic enhancement effect of rigid inorganic nanoparticles and flexible ionic liquids.The main work and conclusions of this study are as follows:（1）An enhanced composite filler（IL@Al₂O₃）was prepared by double-bond polymerization of functionalized ionic liquid（ILs）and inorganic nanoparticles（KH570-Al₂O₃）modified by a silane coupling agent.The composite filler was crosslinked with the PUE matrix in situ to form a new impact resistance composite（PUE-IL@Al₂O₃）.The dynamic and static mechanical properties of PUE matrix composites were investigated by adjusting the proportions or compositions of filler.The results showed that PUE-IL@Al₂O₃ material with 1 wt.%composite filler had the best comprehensive mechanical properties.Compared with pure PUE material,the static compressive yield strength,static energy absorption and dynamic impact energy absorption of PUE-1%IL@Al₂O₃ increased by 61.1%,173.9%and 15.5%,respectively.The deformation recovery rate of PUE-1%IL@Al₂O₃ after unloading was about 95%,and the damage degree after impact was relatively light.（2）To further study the impact of interface interaction on the impact resistance of composite materials,Si O₂ nanoparticles with higher surface reactivity were selected to prepare a new impact resistance composite（PUE-IL@Si O₂）based on the experimental exploration in the previous part,and the comprehensive mechanical properties of the composites were studied.The results showed that the PUE-IL@Si O₂ with 2 wt.%composite filler had the best comprehensive mechanical properties.Compared with pure PUE material,the static compressive yield strength,static energy absorption,dynamic impact yield strength and dynamic impact energy absorption of PUE-2%IL@Si O₂ increased by 216.2%,238.9%,190.7%and 18.9%,respectively.The impact damage degree of PUE-2%IL@Si O₂ was relatively light,and the deformation recovery was good.In addition,compared with pure PUE material,the thermal degradation rate and mass loss of PUE-2%IL@Si O₂ composites at high temperatures were reduced by 22.7%and 20.5%,respectively.Comparative analysis of the optimal mechanical properties of two impact resistance composites,the static compressive yield strength,static energy absorption and dynamic impact energy absorption of PUE-IL@Si O₂ composites were 253.8%,37.4%and 21.9%higher than those of PUE-IL@Al₂O₃,respectively,and the impact damage degree of PUE-IL@Si O₂ was relatively light.Therefore,based on the difference of mechanical properties between the two impact resistance composites,this paper proposes that the ionic liquid acts as a gradient-interphase establish a nanoscale interface between inorganic nanoparticles and the PUE matrix,which makes the nanocomposite filler play an interface role and synergistic reinforcement effect,thus effectively improve the impact resistance of PUE-IL@Si O₂ composites.