聚甲醛等温热降解  

The Isothermal Degradation of Polyoxymethylene

作　　者：李惠林[1] 段怡飞[1] 

机构地区：[1]四川大学高分子研究所高分子材料工程国家重点实验室,四川成都610065

出　　处：《四川大学学报（工程科学版）》2005年第4期65-68,共4页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家863计划资助项目(2002AA333070)

摘　　要：通过等温热失重(TG)和残留物红外光谱(FTIR)研究了聚甲醛(POM)在空气条件下的热氧降解动力学及机理,讨论了温度对聚甲醛初始降解速率以及热老化寿命的影响。结果表明,POM热氧降解的初始阶段符合一级反应动力学规律,POM在240℃下的降解速率常数比180℃高出100倍,其在230℃下的热老化寿命小于3min。POM在热氧降解过程中的FTIR分析表明,在1735cm-1处出现了典型的羰基吸收峰,标志着有氧存在下POM的降解遵循自由基引发断链的机理。The kinetics and mechanism of thermooxidative degradation of polyoxymethylene（POM）, and the effects of temperatures on the initial degradation rate and life time of POM, were studied in air by isothermal TG and FTIR analysis of the residue. The results showed that POM follows the first-order kinetic relationship at the first stage of thermal oxidation.The degradation rate constant of POM at 240℃ is I00 times higher than that at 180℃, while at 230℃ the life time is rather shorter than 3 minutes. During thermooxidation of POM, the IR spectrum showed typical absorption at 1735 cm^-1 assigned to the formation of carbonyl group （C = O） which proves the cleavage of carbon-oxygen bond initiated by free-radical mechanism in the presence of oxygen.

关 键 词：聚甲醛 热氧降解 动力学 机理 

分 类 号：TQ326.51[化学工程—合成树脂塑料工业]