摘要
采用热解 /红外联用仪 (Py/FTIR)考察了PVC的热解过程 ,结果表明 ,PVC在 2 0 0℃时开始放出HCl,30 0℃左右达到最大 ,在红外谱图上HCl气体的振 转吸收区是 310 0cm-1～ 2 6 0 0cm-1,有P支和R支出现 ;随后—CH2 —基在 2 86 0cm-1和 2 930cm-1处的吸收明显增强 ,可认为是生成的多烯碎片进一步裂解生成脂肪族化合物的结果 ;同时有芳烃在 16 2 0cm-1、30 10cm-1和 90 0cm-1～ 6 0 0cm-1处的吸收出现。这是由于除了部分多烯碎片无规则断裂形成脂肪烃类物质的挥发分外 ,还有一部分通过分子重排、环化形成芳烃结构 ,其中的一部分以芳烃类物质进入挥发分 ,另一部分聚合形成稠环芳香族物质 ,最后变成焦粒。通过上述研究 ,提出了PVC的热解机理 ,即PVC首先脱出HCl气体 ,进一步热解产生多烯结构 ,并通过分子重排、环化形成芳烃结构。
This paper describers the pyrolysic process of PVC by means of CDS2000 pyroprobe with a Fourier Transform infrared spectrometer. The pyrolysis instrument is designed to fit into the sample compartment of a standard FTIR bench, and places the filament of pyrlprobe directly in the light path, thus continuous monitoring of the i.r. spectrum of evolved products. A sample of PVC was heated at 25?℃/min and 20?000?℃/s to a final temperature of 1?000?℃. IR scans were taken during the pyrolysis. The resulting spectrum shows the recognizable pattern of HCl in the gas phase, both P and R branches are present and well resolved. It has been deduced that PVC degrades via side group elimination of HCl from polymer backbone, forming a polyene which fragments further to produce aromatics. By correlating the time with the heating rate, the temperature at which product evolution begins can be determined. Pyrolysis/FTIR can be thus as a useful means of probing the process of pyrolysis.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2002年第6期569-572,共4页
Journal of Fuel Chemistry and Technology
基金
国家自然科学重点基金 ( 19935 0 10 )~~
