Influences Of Synthetic Process On Property Of Polyurethane/Polymethacrylate Interpenetrating Polymer Network Damping Materials

Because of the excellent damping performance, interpenetrating polymer networks (IPNs) play an important role in vibration and noise control of rail transportation. The research and development of IPNs has profound theoretical and practical significance. The aim of this paper is to investigate the influences of synthetic process on the mechanical property, the damping capacity and the heat aging resistance of polyurethane/polymethacrylate (PU/PMA) IPNs.The PU/PMA IPNs were synthesized by sequential method. The influences of the composition, the content of crossing-linker, the curing temperature and graphite filler on the damping properties of IPNs were analyzed.The damping performances were evaluated by dynamic mechanical thermal analysis (DMA) and cantilever beam resonance methods. According to the experimental results, the damping properties of IPNs were improved by optimizing the synthetic process. Among them, the IPNs with the composition of PU/PMA=40/60and the crossing-linker content of TMP%=2%which were cured at80℃exhibit the highest loss factor. The phenomenon is explained by the effects of synthetic process on the compatibility of IPNs.Special attention was paid to the influences of graphite size and content on the damping properties of IPN composites. As to the composites with different graphite sizes, the loss factor of the composites increases with the decreasing graphite size. The performance is much more significant at higher experimental temperature. In terms of graphite content, the damping properties of IPN composites are enhanced obviously as the graphite content is beyond10wt%. Moreover, the loss factor of IPN composites increases from0.73to0.84, and the damping range (tanδ≥0.3) of temperature and frequency is79℃and2500Hz respectively. However, the lower graphite content causes a little improvement of damping capacity of the composites.In addition, the thermal aging experimental results show that the damping properties of IPNs decrease with the increasing temperature and the extension of time. The addition of graphite fillers causes the decrease even more seriously for the chemical reaction caused by silane coupling agent.