Thermal degradation kinetics of poly(acrylate/α-methyl styrene) copolymers
Thermal degradation kinetics of poly(acrylate/α-methyl styrene) copolymers
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DOI：
10.1016/j.polymdegradstab.2015.10.003
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发表时间：
2016-06
影响因子：
5.9
通讯作者：
Qian Li;Ying Wang;Mengjin Fan;Junying Zhang;Jue Cheng
中科院分区：
文献类型：
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作者：
Qian Li;Ying Wang;Mengjin Fan;Junying Zhang;Jue Cheng
以丙烯酸丁酯（BA）、丙烯酸2-乙基己酯（2-EHA）和α-甲基苯乙烯（α-MeSt）为单体，通过乳液聚合制备了丙烯酸酯/α-MeSt共聚物。用1H-NMR证实了共聚物中α-MeSt单元的含量。为了阐明共聚物的热降解现象，采用差示扫描量热法（DSC）监测了共聚物在低温下的初始分解过程，而没有明显的重量损失，并采用凝胶渗透色谱法（GPC）表征了共聚物和热处理后共聚物的分子量。采用热重分析（TGA）研究了共聚物的热降解行为，并采用Kissinger法、Flynn-Wall-Ozawa（FWO）法和Kissinger-Akahira-Sunose（KAS）法对共聚物的热降解动力学进行了系统研究。GPC和DSC测试表明，聚乙烯的键断裂与纯聚丙烯酸酯相比，（丙烯酸酯/α-MeSt）共聚物在较低的温度下发生热降解，热降解动力学分析表明，随着α-MeSt含量的增加，共聚物的热降解活化能和指前因子均增大;因此，在本发明中，聚合物的分解反应速率常数（丙烯酸酯/α-MeSt）共聚物的聚合度随着α-MeSt的结合量的增加而增加。当降解温度高于320 °C时，共聚物中的MeSt单元。FWO法和KAS法表明，在相同转化率下，α-MeSt单元含量较高的共聚物样品的降解活化能高于α-MeSt单元含量较低的共聚物样品。
The poly(acrylate/α-MeSt) copolymers were prepared by emulsion polymerization of butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA) and α-methyl styrene (α-MeSt). The contents of α-MeSt units combined into the copolymers were confirmed by1H-NMR. In order to clarify the thermal degradation phenomenon of the copolymers differential scanning calorimetry (DSC) was used to monitor the initial decomposition of the copolymers at low temperatures without obvious weight loss, and gel permeation chromatography (GPC) was used to characterize the molecular weights of the copolymers and the thermally treated ones. The thermal degradation behavior of these copolymers was investigated by thermogravimetry (TGA), and the thermal degradation kinetics was systematically investigated by both Kissinger method, Flynn–Wall–Ozawa (FWO) method and Kissinger–Akahira–Sunose (KAS) method. The GPC and DSC measurements showed that bond breaking of the poly(acrylate/α-MeSt) copolymers occurred at a relatively low temperature compared with neat polyacrylates; the thermal degradation kinetics analysis verified that both the activation energy and pre-exponential factor increased with increasing the content of α-MeSt units in the copolymers; consequently, the decomposition reaction rate constant of the poly(acrylate/α-MeSt) copolymers increased with increasing the amount of combined α-MeSt units in the copolymers when the degradation temperature was higher than 320 °C. FWO method and KAS method revealed that the value of the degradation activation energy of the copolymer sample with higher content of α-MeSt units was higher than that of the copolymer sample with lower content of α-MeSt units at the same conversion.