PP-R双螺杆挤出熔体输送和降解行为的研究

Study on melt-conveying and degrading behaviors of PP-R in twin-screw extruder

对无规共聚聚丙烯(PP-R)在ZSK-300型双螺杆挤出机中熔体输送特性和热降解行为进行了研究,计算了ZSK-300的最大挤出量,分析了熔体输送流场;并对加料量、熔体流动指数、助剂量、熔体温度等工艺操作条件对熔体输送和降解行为的影响进行了讨论。结果表明,加料量的改变需要适当调整加热温度;粉料熔体流动指数的微小波动,对挤出物的质量和挤出过程的稳定性没有影响;降低熔体挤出温度,可明显降低PP-R的热氧降解。

The melt-conveying character and degrading behavior of ethylene-propylene random copolymer (PP-R) was studied in a twin-screw extruder of model ZSK-300. The maximum extrusion output was calculated for the extruder and the flow field for melt-conveying was analyzed. The effects of process parameters such as feeding rate, melt flow index, additive dosage and melt temperature on melt-conveying and degrading behavior were discussed. The results show that heating temperature of the extruder needs to be adjusted as feeding rate varies. A slight fluctuation in melt flow index of the PP-R power does not affect quality of extrudate and stability of extruding process. The thermo-oxidative degradation of PP-R can be significantly depressed as the extruding temperature of the melt decrease.