PMMA、PS和SAN的热稳定性比较研究

A Comparison of Thermal Stability of PMMA,PS and SAN

通过热重分析对聚甲基丙烯酸甲酯(PMMA)、聚苯乙烯(PS)和苯乙烯一丙烯腈共聚物(SAN)在空气气氛中的非等温和恒温热稳定性进行了比较,用 Flynn-Wall-Ozawa 方程求得其不同质量保留率时的热降解反应表观活化能。结果表明,在非等温热降解实验中,SAN 的热分解起始温度为307℃,热稳定性最好;PS 的热分解起始温度为264℃,热稳定最差;PMMA 的热分解起始温度为282℃,热稳定性居中。通过恒温热分解实验发现,SAN 的适宜脱挥温度为275℃,PMMA 的适宜脱挥温度为230℃,PS 的适宜脱挥温度为210℃。求解的热分解表观活化能表明,SAN 和 PS 为减速型热分解反应,PMMA 为加速型热分解反应。

The non-isothermal and isothermal heat stability of poly（methyl-methacrylate） （PMMA）, polystyrene （PS） and styrene/acrylonitrile copolyrner （SAN） were compared through thermalgravimetry （TG） analysis in air atmosphere. The heat decomposition apparent activation energies of the samples at different weight residuary stages were obtained using Flynn-Wall-Ozawa equation. The mode of the heat decomposition reaction was judged by the change tendency in the decomposition activation energies. In non-isothermal heat decomposition experiments the initiative thermal degradation temeperatures of SAN, PMMA, and PS were 307, 282, and 264 ℃, respectively. The isothermal heat decomposition experiment indicated that the optimal volatilization temperatures of SAN, PMMA and PS were 275, 230, and 210 ℃, respectively. It was deduced from the heat decomposition appearance activation energy that the reaction mode of SAN and PS were accelerated, but of PMMA was decelerated.