聚乙烯燃烧和阻燃的热分析研究

CONBUSTION.AND FLAME-RETARDATION OF POLYETHYLENE STUDIED BY THERMOANALYSIS

聚乙烯是一种极易燃烧的高分子材料,氧指数仅17.6,随着其应用面的拓宽和现代社会对防火要求的提高,聚乙烯的阻燃成了越来越重要的课题。目前,聚乙烯及其共混物的阻燃配方已不计其数,理论探讨也有一些报道,但由于对阻燃效果与阻燃剂的性质之间的内在联系尚缺乏足够的认识,所以阻燃剂的选择仍主要依赖于经验及大量的配方试验,缺少系统有效地选择阻燃剂的方法。

Four halogen-containing compounds, decatbromodiphenyloxide (DBDPO), chlorinated paraffin-70(Cl-70), polyvinylchloride(PVC) and chlorinated polyethylene (CPE) were conbi-ned with antimony trioxide(Sb3O3) to constitue flame-retardents of polyethylene. DSC and TG investigations show that conbustion of PE is thermal oxygenolysis process through free radical reaction. Halogen-containing compounds decompose and release HX, which reacts with Sb2O3 to give SbX3, before PE burning. These substances can retard the conbustion by catching free radicals. △Td, temperature difference between thermal oxygenolysis of PE and decomposition of halogen-containing compound, is defined to evaluate the efficiency of the flame-re-tardent. Retardents with proper values of △Td have higher efficiency than those with too large or minus values. Among four compounds used in this paper, DBDPO and Cl-70 are effective flame-retardents, while PVC and CPE are of lover efficiency.