含氯对位芳香族聚酰胺热分解过程中的TG-FTIR与Py-GC/MS分析

Study on the Thermal Degradation Process of Chlorinated Para-aromatic Polyamide by TG-FTIR and Py-GC/MS

对于两种不同相对分子质量的含氯对位芳香族聚酰胺(Cl-PPTA)薄膜样品和聚对苯二甲酰对苯二胺(PPTA)粉末样品,采用热失重-傅里叶变换红外光谱(TG-FTIR)和裂解色谱-质谱(Py-GC/MS)分析其热分解过程.由TG分析得到了样品在空气和氮气气氛下的特征性温度,表明在有氧情况下Cl-PPTA的热稳定性比PPTA好,而且在氮气气氛下高温残留率比PPTA高.在空气气氛下,ClPPTA热分解的主要产物为HCN、CO、CO2、NO2和H2O,且CO2吸收峰最强;将Cl-PPTA薄膜在氮气气氛下进行高温处理,对得到的产物进行IR分析,显示羰基吸收峰逐渐减弱且出现新末端基团或官能团;而高温下Py-GC/MS的结果表明CO2和苯环是Cl-PPTA主要的裂解产物;随着裂解温度的改变,Cl-PPTA气相色谱和质谱发生很大变化,这些裂解产物可以帮助分析Cl-PPTA薄膜的裂解机理.

The thermal degradation behaviors of two chlorinated para-aromatic polyamide（Cl-PPTA） thin films and poly-p-phenylene terephthamide （PPTA） powder were measured by thermogravimetry-Fourier transform infrared spectrum （TG-FTIR） and pyrolysis-gas chromatography/mass spectrometry （Py-GC/MS）. The characteristic temperature of three samples in air and nitrogen atmosphere was obtained by TG analysis, which indicated that C1-PPTA had excellent thermal stability in air condition and had better higher char residue （CR） than PPTA in nitrogen condition. The gases released by the pyrolysis of CI-PPTA in air were mainly HCN, CO, COz, NO2 and Hz O, and the absorption peaks of COz were the strongest. With IR analysis on the CR of C1-PPTA films under high temperature treatment in nitrogen atmosphere, the carbonyl absorption peak became weak and the new end groups or the function groups appeared. Results of Py- GC/MS in different temperature showed that the main pyrolysates were COz and benzene. The Py-GC/MS of CI-PPTA greatly changed due to the changes of pyrolysis temperature. And all these pyrolysates can help to study the suggested pathway for the formation of the major degradation products of CI-PPTA film.