聚氨酯/乙烯-乙酸乙烯酯聚合物弹性体耐磨性及微观分析

为了探究聚合物弹性体耐磨性及微观形态,本文以沙柳液化产物与MDI反应生成聚氨酯为预聚体,EVA/PU进行接枝共聚形成聚合物弹性体,并利用扫面电镜探针显微镜等对聚合物弹性体进行了测试分析。结果表明:当含EVA为10%时材料的硬度达到最大,磨耗率也是最低的,分子的结晶度增大,两相的相容性也达到最佳状态。对EVA/PU弹性共体拉伸断裂面的扫面分析,发现随着EVA的加入量的增大,断面呈现由脆性断裂向韧性断裂过渡,并且在断裂的微观区出现了明显塑性变形。在扫描探针显微图下可以看到EVA/PU之间发生的接枝共聚现象,分子变小,同时分子的高度增加。这就说明EVAL中的游离羟基与PU预聚体发生了接枝反应。

The analysis of abrasion resistance and microstructure on Polyurethane / Ethylene-Vinyl Acetate polymer lastomer

Flame retardancy of hexaphenoxycyclotriphosphazene（HPTCP） in Polycarbonate/acrylonitrile- styrene-butadiene copolymer（PC/ABS） alloy was studied by limiting oxygen index（LOI） measurement, vertical burning and cone calorimeter test（CCT）. The results showed that HPTCP had a good flame retardancy in PC/ABS. When the loading of HPTCP was 15% based on the total weight of the composite, the LOI of the fla me retarded PC/ABS was 25.0% and the flame retarding class meet FV-0, and the heat release rate, total heat release, peak heat release rate, average heat release rate,average effective heat of combustion and mass loss were significantly decreased compared with PC/ABS. The thermogravimetric results showed that HPTCP a less impact on the thermal stability of PC/ABS. The thermogravimetric results and the analysis of the residues obtained in the cone calorimeter test indicated that HPTCP played a flame retardancy mainly by condensed phase mechanisms, where the addition of HPTCP could effectively retarted the decomposition and promoted the carbonization of PC/ABS, and the formed intumescent layer resulted in a flame retardancy by the barrier effect on heat, air and decomposition products.