端羟基超支化聚酯的稳定化改性及热分解行为  

Stabilization Modification and Thermal Degradation Behaviors of Hydroxyl-terminated Hyperbranched Polyesters

作　　者：刘晶如[1] 巢玲玲[1] 丁镜[1] 俞强[1] 

机构地区：[1]常州大学材料科学与工程学院,江苏常州213164

出　　处：《高校化学工程学报》2014年第2期346-351,共6页Journal of Chemical Engineering of Chinese Universities

基　　金：江苏省大学生科技创新基金(SCZ1117400050)

摘　　要：以长链烷基酸为改性剂,对以三羟甲基丙烷为核、二羟甲基丙酸为支化单体合成的端羟基超支化聚酯进行端基稳定化改性。采用羟值滴定和核磁共振氢谱(1H-NMR)表征超支化聚酯的改性程度;采用热重-微商热重分析(TG-DTG)研究了代数、端基类型以及改性程度对超支化聚酯热稳定性和热分解行为的影响。结果表明,将不稳定的端羟基转变为热稳定的端烷基后,超支化聚酯的热稳定性明显提高,且改性程度越高,或长烷烃链越短,聚合物的热稳定性越好。超支化聚酯的热分解主要包括两个失重阶段,分别对应于由大量端基所组成的"壳"的破坏以及由大量C-C单键所组成的骨架(即"核")解体。极性端羟基的含量越小或非极性端烷基的含量越大,第一失重峰越不明显。A series of hydroxyl-terminated hyperbranched polyesters with 1,1,1-trimethylolpropane as thecore and 2,2-bis（hydroxymethyl）propionic acid as the AB2-monomer were end-capped with long-chain n-alkylcarboxylic acids. The modification degree of hyperbranched polyesters was confirmed by titration of hydroxylvalues and proton nuclear magnetic resonance （1H-NMR）. The influence of generation number, end-group type,and degree of modification on thermal stability and thermal degradation behavior of hyperbranched polyesterswas investigated by thermogravimetric-derivative thermogravimetric analysis （TG-DTG）. The results show thatthe thermal stability of hyperbranched polyesters is highly improved after modification. The increase ofmodification degree or the shortening in the alkane chain length of the end groups enhances the thermal stabilityof hyperbranehed polyesters. The decomposition process of hyperbranched polyesters is composed of twostages, i.e. damage of the shell （composed of numerous end groups） and collapse of the sheleton （＂core＂composed of lots of C-C single bonds）. This study indicates that the first weightlessness peak becomesnegligible with the decrease of polar hydroxyl-terminated groups or with the increase of nonpolaralkyl-terminated groups.

关 键 词：超支化聚酯 端基 稳定化 热分解行为 

分 类 号：TQ317[化学工程—高聚物工业]