无规聚苯基硅倍半氧烷阻燃聚碳酸酯的性能

Flame Retardant Properties of Polycarbonate/ Irregular Polyphenylsilsesquioxane Composites

采用笔者自制的无规聚苯基硅倍半氧烷(IPPS)与聚碳酸酯(PC)通过双螺杆挤出机熔融共混,制得不同含量IPPS的PC/IPPS复合物。利用极限氧指数(LOI),垂直燃烧等级(UL-94)和锥形量热仪对PC/IPPS复合物的燃烧性能进行了表征;通过拉伸强度、弯曲强度及弯曲模量对PC/IPPS复合物的力学性能进行了表征;通过热失重分析了IPPS对PC热性能的影响。实验表明,当添加质量分数8%的IPPS时,可以使PC的极限氧指数(LOI)从26%提高到35.5%,UL-94(1.6mm)燃烧级别从无级别提高到V-0;热释放速率峰值(PHRR)从570.8 kW/m2降到267.3 kW/m2。燃烧后的炭层表面被白色的二氧化硅覆盖,很好地阻隔辐射热和氧向基材的传递。IPPS使得PC的力学性能有轻微的下降,不改变PC的降解路径。

Irregular polyphenylsilsesquioxane （IPPS） was independently synthesized in our laboratory. IPPS mixed with polycarbonate （PC） by the twin-screw extruder to prepare PC/IPPS composites. The flammability of the PC/IPPS composites was characterized by limiting oxygen index （LOI）, UL 94 burning rating and Cone calorimeter test. The mechanical properties of PC/IPPS composites, such as tensile strength, flexural strength and modulus, were tested. The thermal properties were analyzed through the thermal gravimetric analysis （TGA）. The results show that the LOI value of PC/8 % IPPS composite can achieve 35.5 % comparing with 26 ~,6 of pure PC, and UL94 （1.6mm） can reach V-0 rating. The peak heat release rate （PHRR） decreases from 570.8 kW/m2 to 267.3 kW/m2 in the 8% IPPS loading. The surface of char residues is covered by white silica, which can prevent transfer of the heat and oxygen to PC matrix. The mechanical properties of PC with IPPS loading has a slightly decrease. However, the addition IPPS has no effect on the thermal degradation path of PC matrix.