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首页> 外文期刊>Journal of Applied Polymer Science >Thermal Degradation Mechanism of Poly(ether imide) by Stepwise Py-GC/MS
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Thermal Degradation Mechanism of Poly(ether imide) by Stepwise Py-GC/MS

机译：逐步Py-GC / MS分析聚醚酰亚胺的热降解机理

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摘要

The thermal degradation ofpoly(ether imide) (PEn was studied through a combination of thermogravimetric analysis and stepwise pyrolysis-gas chromatogra- phy/mass spectrometry (Py-GCIMS) techniques with consecutive heating of the sam- ples at fixed temperature intervals to achieve narrow temperature pyrolysis conditions. The individual mass chromatograms of various pyrolysates were correlated with py- rolysis temperatures to determine the pyrolysis mechanism. The major mechanisms were two-stage pyrolysis, involving main-chain random scission, and carbonization. In the first stage, the scission of hydrolyzed imide groups, ether groups, and isopropyli- dene groups produced CO+CO_2 and phenol as the major products and was accompanied by chain transfer of carbonization to form partially carbonized solid residue. In the second pyrolysis stage, the decomposition of the partially carbonized solid residue and remaining imide groups formed CO+CO_2 as the major product along with benzene and a small amount of benzonitrile. The yield of CO+CO_2 was the largest fraction in the total ion chromatogram of the evolved gas mixtures. Hence, the thermal stabilityofthe imide group was identical to the maximum thermogravimetry loss rates in the two- stage pyrolysis regions. Afterward, carbonization dominated the decomposition of the solid residue at high temperatures.
机译：通过热重分析和逐步热解-气相色谱/质谱（Py-GCIMS）技术的组合研究聚醚酰亚胺（PEn）的热降解，并以固定的温度间隔连续加热样品以实现窄高温裂解条件下，将各种裂解物的质量色谱图与裂解温度相关联，确定裂解机理，主要机理为两阶段裂解，涉及主链随机断裂和碳化。水解的酰亚胺基团，醚基团和异丙基亚烷基产生的主要产物为CO + CO_2和苯酚，并伴随着碳化的链转移反应，形成了部分碳化的固体残渣;在第二个热解阶段，部分碳化的分解固体残留物和剩余的酰亚胺基团与苯和sm一起形成了主要产物CO + CO_2所有量的苄腈。在逸出的气体混合物的总离子色谱图中，CO + CO_2的产率最大。因此，酰亚胺基团的热稳定性与两阶段热解区的最大热重损失速率相同。之后，碳化作用主导了高温下固体残留物的分解。

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