裂解气相色谱质谱法研究废旧ABS塑料的热降解行为

采用裂解气相色谱质谱联用技术对ABS塑料的热降解行为进行了研究.在氦气氛围中,500℃下对ABS进行热裂解,通过色谱质谱联用仪对裂解产物进行了定性分析,共鉴定出苯乙烯、甲苯和4-苯基丁腈等31种裂解产物.根据裂解产物信息和有机物热裂解反应的原理对ABS的热裂解反应机理作了探讨.ABS塑料的热降解过程是典型的自由基历程,解释了裂解产物中芳香烃类化合物、脂肪烃类化合物、腈类化合物和含溴酚类化合物的生成机理.ABS的高温降解过程不是三种结构单元降解过程的简单累加,三种结构单元在其降解过程中相互明显影响,最终导致裂解产物在结构和类别上的多样性.废旧塑料ABS热裂解过程会产生多种有害污染物,因此,选择合适的裂解工艺条件,既可得到更多有用的裂解产物,又可减少对环境的污染.

Study on Thermal Degradation of Waste ABS by Pyrolysis GC/MS

The thermal degradation of ABS is investigated by pyrolysis gas chromatography mass spectrometry （GC-MS） in the presence of helium. GC-MS is used for qualitative analysis of the pyrolysis products of ABS under 500℃. Altogether 31 pyrolysis products are detected, including styrene, toluene and 4-phenyl butyronitrile, etc. Pyrolysis reaction mechanism of ABS is discussed according to the information of pyrolysis products and the reaction principle of organics thermal cracking. The thermal degradation of ABS is a typical radical chain mechanism, and the generation mechanisms of aromatic hydrocarbon, aliphatic hyfrocrbon, acrylic compounds and compounds containing bromophenol are explained. The thermal degradation of ABS is not a simple summation of three structural monomers, because the three constituents interact with each other significantly, the pyrolysis product has variety structures and categories. The pyrolysis products of the thermal degradation of ABS contain a lot of harmful substances, so the suitable technology of pyrolysis should be applied to obtain more useful pyrolysis products and decrease the environment pollution.