摘要
对比分析了3批聚合度为1 000的聚氯乙烯(PVC)树脂的热稳定性、相对分子质量及其分布、偏二氯乙烯链节含量、分子链双键的相对含量及重金属离子含量。结果发现,热稳定性差的树脂双键相对含量较高,重金属离子相对含量明显高出正常批次料;同时还检测出了偏二氯乙烯链节。研究认为,引起配混料和医用粒料颜色发暗、雾度升高、制品黄色指数高的主要原因首先是树脂重金属离子含量高,对树脂老化起到了催化作用:其次是原料单体中的杂质参与了聚合,形成了分子链缺陷,导致热稳定性下降。
This paper analyzed 3 batches of polyvinyl chloride （PVC） resins with polymerization degree of 1 000, aiming at studying their thermal stability via comparison of relative molecular mass and its distribution, content of vinylidene chloride monomeric unit, relative content of double bond in molecular chain and content of heavy metal ions. The results show that the batch with inferior thermal stability has relatively higher content of double bond and its content of heavy metal ions also notably higher than other eligible batches, besides the existence of vinylidene chloride monomeric unit as detected in the analysis. Further investigation demonstrates that the high content of the heavy metal ions is the primary factor that leads to severe dimness in colour and increased haze of the resin compounds and the medical resin granules, and higher yellow index of the articles, because the heavy metal ions accelerate the aging process of the resin. In addition, the impurities in the monomer, which can also take part in the polymerization and form structural defects in the molecular chains, deteriorate the resin＇s thermal stability.
出处
《合成树脂及塑料》
EI
CAS
北大核心
2008年第2期28-30,共3页
China Synthetic Resin and Plastics
关键词
聚氯乙烯
热稳定性
老化白度
polyvinyl chloride
thermal stability
post-ageing whiteness
