【摘要】 本文对不同立构的聚甲基丙烯酸(PMAA)进行了热表征。实验结果表明,在30℃～200℃内未出现玻璃化转变。间同PMAA分别在-245℃和-280℃发生脱水反应和脱羧,而全同PMAA只在-185℃观察到脱水反应。这种热稳定性的明显差别与不同立构PMAA链上相邻羧酸距离有关。实验数据证实PMAA脱水反应为无规反应,服从一级动力学反应方程。脱水温度和间同立构含量成正比,脱水反应活化能间同PMAA比全同PMAA高～7Kcal/mol。更多还原

【Abstract】 A comprehensive thermal characterization of the various stereoregular polymethacylic acid (PMMA) was conducted via mass spectrometry and thermal analysis. The results showed that no glass transition occurred in the range from 30℃ to 200℃of these polymers was observed. Maximun water evolution, due to anhydride formation, and carbon dioxide evolution, due to decarboxylation, occurred at-245℃℃, respectively, in syndiotactic PMAA, but only water evolution at -185℃ in isotactic PMAA. The relationship between the thermal stability and stereoregula-rity of PMAA was discussed. The activation energy of the dehydration was obtained.更多还原