耐熱性共聚酯之熱降解

Thermal Degradation of Heat Resistant Copolyesters

蔡宏斌(Hong-Bing Tsai) ； 游建文(Jiang-Wen You) ； 蔡瑞禧(Ruey-Shi Tsai)

《宜蘭技術學報》 6期 (2001/06) Pp. 45-56

https://doi.org/10.6179/nit.2001.06.16

摘要

共聚酯係由4,4'聯苯二甲酸二甲酯，己二酸與烷撐二醇（1,5-戊二醇及1,6-己二醇）以熔聚縮合而製得，其組成以NMR分析測定之。另以相同方法製得四種均聚酯，聚（4,4'聯苯二甲酸己二酯）（BB6），聚己二酸己二酯（AA6），聚（4,4'-聯苯二甲酸戊二酯）（BB5）及聚己二酸戊二酯（AA5）供作比較。聚酯在氮氣及空氣下以TGA測其熱重（TG）曲線。在空氣下所有均聚酯及共聚酯皆明顯地較在氮氣下易於熱降解。組成對於共聚酯的熱降解的影響相當有趣。AA6及AA5明顯的較BB6及BB5易於熱降解。而無論是在氮氣或空氣下，二酸單體中己二酸莫耳分率接近0.5的共聚酯的熱降解情形較接近BB6及BB5。也就是說己二酸酯含量不高（x≦0.5）時，共聚酯的熱安定性受己二酸酯單位的影響並不很大。

關鍵字

共聚酯 ； 熱熔膠 ； 熱降解

並列摘要

Copolyesters with 4,4'-bibenzoate unit were prepared by melt polycondensation of dimethyl-4,4'-bibenzoate, adipic acid and an alkylene glycol(1,5-pentanediol or 1,6-hexanediol) , and their compositions were determined by NMR. Four homopolyesters, poly (hexamethylene 4,4'-benzoate)(BB6), poly (hexamethylene adipate) (AA6), poly (pentamethylene 4,4'-bibenzoate) (BB5) and poly (pentamethylene adipate) (AA5) were also prepared as comparison. The thermogravimetric curves of the homopolyesters and copolyesters were determined under nitrogen as well as under air atmosphere. All the polyesters were found to degrade more easily under air than under nitrogen. Composition influenced the thermal degradation in an interesting way. AA6 and AA5 showed easier degradation in comparison with BB6 and BB5. However, the copolyesters with a molar fration of adipic acid in diacid monoers, x, close to 0.5 exhibited thermal degradation behavior similar to that of BB6 and BB5. In other words, as the adipic acid content was not high enough (x≦0.5), the adipate unit had little influence on the thermal stability of the copolyesters.

並列關鍵字

Copolyesters ； Hot melt adhesives ； Thermal degradation