木塑复合材料热解特性

Pyrolysis characteristics of wood-plastic composites

通过热重分析(TGA)和裂解/气质联用(Py-GC/MS)对杨木/高密度聚乙烯(HDPE)木塑复合材料(WPC)进行热解,考察了木粉和聚烯烃塑料热解过程中的相互作用。结果表明:生物质和塑料热解过程中存在明显的协同作用,杨木在较低的温度下即开始发生热解,其提供的自由基参与了聚烯烃热解反应,产生了更多的轻质烃类产物。而聚烯烃分解产生的碳氢化合物向生物质分解产生的自由基提供氢,促进挥发性物质生成,部分抑制了活性自由基进一步聚合结焦,得到了更多的挥发性产物和减少了固体残炭。

Thermo-gravimetric analysis（TGA）and pyrolysis-gas chromatography/mass spectrometry（Py-GC/MS）were employed to investigate the pyrolytic behavior and primary pyrolysis product distribution of the pyrolysis of wood-plastic composites（WPC）.The mutual effects of poplar wood and high-density polyethylene were detailed discussed during pyrolysis.The results showed that a significant synergistic effect between plastic and biomass was present in the pyrolysis process of WPC.The Py-GC/MS indicated that due to the lower temperature of biomass component decomposition compared with polyolefins,free radicals are formed from biomass pyrolysis and participate in reactions of plastic decomposition,initiating the scission of the synthetic polymer chain and yielding more light paraffins.The TGA indicated that the experimental char yield of WPC was lower than theoretical ones at final pyrolysis temperature.The reason could be that polyolenic polymers provide hydrogen during thermal process with wood biomass and recondensation or recombination of thermal cracking products of biomass is reduced,resulting in the less amount of char production and enhancement of volatile products formation.