摘要
采用核磁共振氢谱 (H NMR)分析了几种具有代表性的聚甲醛 (POM)分子链中共聚单元的序列结构特征 ,并考察了其序列结构与热稳定性及结晶速率的关系。结果表明 ,共聚单元中亚氧甲基 -亚氧乙基 -亚氧甲基(MEM)链段含量越小 ,则共聚POM耐热性越差 ,且在热经时处理的条件下 ,半结晶时间 (t1/ 2 )增加越显著 ;随热经时处理时间变长 ,共聚POM的结晶速率变慢与热分解导致的—CH2 —CH2 —O—含量相对提高有关 ,而均聚POM的结晶速率变慢与热分解导致的端基含量增加有关 ;
The sequence structure of copolymerization monomers in several kinds of representative polyoxymethylene(POM) were analyzed by means of H NMR technique, and the relationship between the sequence structure and the thermostability or the crystallization rate of POM was investigated. The results indicated that the less the content of MEM units among copolymerization monomers, the lower the thermostability of POM; moreover, with less MEM units, the crystallization rate became lower, i.e., t 1/2 markedly increased when POM was placed under the same condition of temperature and time. For co POM, the decrease in crystallization rate was related to the relative increase in —CH 2 —CH 2 —O— content due to thermal decomposition; however, as to homo POM, it was related to the increase in the content of end groups due to thermal decomposition. As a result of varied content of MEM units, the changing tendencies of heat resistance and crystallization rate were verified to be coincident for various POM macromolecules investigated.
出处
《工程塑料应用》
CAS
CSCD
北大核心
2004年第6期46-49,共4页
Engineering Plastics Application
