摘要
采用热失重-傅立叶变换红外光谱（TGA—FTIR）联用技术研究了空气气氛下ABS树脂的热稳定性及热氧降解失重情况。研究了ABS在4个不同升温速率下的失重情况；采用TGA—FTIR联用技术对10℃／min等速升温下ABS失重过程的逸出气体进行分析；采用热分解动力学方法分析ABS的热氧降解过程，计算热分解活化能。结果表明，ABS的TGA曲线有两个失重区间：第一区间是ABS的急剧氧化降解过程，活化能（E。）为191．8～262．8kJ·mol^-1，第二区间是成炭产物的氧化，Ea约为139．7kJ·mol^-1；升温速率越小，ABS热氧降解速率越慢，交联成炭产物越多，有利于抑制ABS的降解；由FTIR测试和Ea变化发现，热氧降解反应为多步复杂反应，初期时氧化反应和氧化断链同时进行，并以氧化断链反应为主，随着分子链上产生的双键增多发生交联反应．失重率大于80％时开始炭化反应．最终交联炭层发牛氧化反应牛成CO2。
Thermal stability and thermo-oxidative degradation of ABS resin were studied by TGA - FTIR in air atmosphere. The weight loss of ABS resin at four different heating rates and the evolved gas were investigated at a constant heating rate of 10 ℃/min by TGA and TGA - KFIR, respectively. The thermo-oxidative degradation process of ABS resin was studied and the activation energy of degradation was calculated based on the thermo-decomposition kinetics. Results showed that two stages of weight-loss appeared on the ABS degradation curve： the first stage corresponded to the rapid oxidative degradation of 90% ABS with activation energy（Ea ） of 191.8 -262. 8 kJ · mol^-1 and the second stage corresponded to the oxidation of residual char with Ea about 139.7 kJ · mol^- 1 It was found that the thermo-oxidative degradation of ABS became slower with the decrease of heating rate and more residual char was formed favoring the suppression of the thermo-oxidative degradation of ABS. The FT- IR spectra and the variation of Ea also indicated that the process of thermo-oxidative degradation was a complex multi-step reaction. The oxidation reaction and mainly the oxidative chain scission reaction occurred simultaneously at the initial stage of thermo-oxidative degradation. As the double bond generated from the molecular chain increased, cross-linking reaction occurred. When the weight loss was greater than 80% , carbonization reaction began, and finally, oxidation reaction occurred at the cross-linking carbon layer to generate CO2.
出处
《分析测试学报》
CAS
CSCD
北大核心
2010年第8期777-781,共5页
Journal of Instrumental Analysis
