典型废塑料热解行为和动力学研究

Study of pyrolysis behavior and kinetics of typical waste plastics

对聚苯乙烯(PS)、丙烯腈-丁二烯-苯乙烯共聚物(ABS)单体及其与聚丙烯(PP)、聚氯乙烯(PVC)、聚乙烯(PE)的混合物进行了热重(TG)和差示扫描(DSC)实验,研究了PS和ABS单组分的热解特性和动力学参数,分析了PS和ABS对典型废旧塑料混合物(PP/PVC/PE)共热解行为的影响。结果表明,PS和ABS的热解反应为一步完成,剧烈热失重时间分别为3.4 min和4.8 min,PS的最大热解速率高于ABS,且ABS的热稳定性强于PS。对比两种混合物的实验结果可以发现,ABS与PS的加入使PP/PVC/PE混合物的残余质量增加,热解第二阶段最大速率降低。采用Kissinger法得到PS和ABS活化能为177.360 kJ/mol和188.566 kJ/mol,通过Criado法、Coast-Redfern法验证了PS和ABS的热解机理分别为随机成核随后生长的A3/2和收缩圆柱体R2。

This article deals with polystyrene(PS),acrylonitrile-butadiene-styrene copolymer(ABS)single products and their mixtures with polypropylene(PP),polyvinyl chloride(PVC),and polyethylene(PE)in thermogravimetric(TG)and differential scanning(DSC)experiment.The pyrolysis characteristics and kinetic parameters of PS and ABS single components were studied,and the influence of PS and ABS on the co-pyrolysis behavior of typical waste plastic mixtures(PP/PVC/PE)was analyzed.The results show that the pyrolysis reaction of PS and ABS is completed in one step,and the severe thermal weight loss time is 3.4 minutes and 4.8 minutes,respectively.The maximum pyrolysis rate of PS is higher than that of ABS,and the thermal stability of ABS is stronger than that of PS.Comparing the experimental results of the two mixtures,it can be found that the addition of ABS and PS increases the residual mass of the PP/PVC/PE mixture and reduces the maximum rate of the second stage of pyrolysis.The activation energies of PS and ABS obtained by Kissinger method are 177.36 kJ/mol and 188.566 kJ/mol.Criado method and Coast-Redfern method verify that the pyrolysis mechanisms of PS and ABS are A3/2 with random nucleation and subsequent growth and a shrinking cylinder R2,respectively.