Pyrolysis of Polytrimethylene Terephthalate(PTT) Fiber by Pyrolysis Gas Chromatography-Mass Spectroscopy

Pyrolysis of polytrimethylene terephthalate(PTT) fiber has been investigated by pyrolysis gas chromatography-mass spectroscopy in the temperature range from 400℃ to 750℃ in order to observe the possible effect of the temperature on its composition of pyrolysates.At 400℃,pyrolysis of molecular chain could occur,only 13 pyrolysates could be identified.The trimethylene moieties bound to the macromolecular core by ester bonds are cleaved at around 400℃.At 550℃-750℃,pyrolysis of molecular chain could completely take place,46 pyrolysates could be found.As the temperature increases,the compositions of pyrolysate are distinctly increased.Several compounds,especially benzoic acid,monopropenyl-p-phthalate,2-propenyl benzoate,di-2-propenyl ester,1,4-benzenedicarboxylic acid,benzene,1,5-hexadiene,biphenyl and 1,3-propanediol dibenzoate could be formed.The thermal degradation mechanism,which is determined by structure and amount of the thermal decomposition products,are described.During pyrolysis of polytrimethylene terephthalate,polymeric chain scissions take place a peeling reaction as a successive removal of the dimer units from the polymeric chain.The chain scissions are followed by the elimination reaction,linkage action and secondary reactions,which bring about a variety fragment.

基于低热容色谱技术便携式气相色谱仪的研制

本研究基于低热容色谱技术研制了便携式气相色谱仪(GC),仪器主要由汽化室、毛细柱及加热控温系统、氢火焰检测器(FID)、电路系统和软件控制系统组成。研制的便携式气相色谱仪采用了多项小型化技术,开发了结构简单、易于实现均匀固体加热的汽化室;采用低热容色谱技术实现毛细柱固体加热,优化了PID控制算法,实现了精确控温;设计了结构简单、体积小的FID检测器;开发了功耗低、体积小、电池供电的电学控制系统;基于LabVIEW开发了包括温度控制、压力控制和数据处理模块的软件控制系统。开发的便携式气相色谱仪具有结构简单、体积小、控温精确、灵敏度高等优点。对仪器性能进行初步测试,仪器检测限优于5×10^(-10)g/s。