加工助剂对HDPE流变性能的影响

Influences of plastics processing aids on rheological properties of high density polyethylene

采用熔体流动速率仪、毛细管流变仪和Haake流变仪研究了极性低聚物、含氟聚合物、有机硅化合物3种加工助剂对高密度聚乙烯(HDPE)流变性能的影响,并对其作用机理进行了探讨。研究发现:熔体流动速率仪和毛细管流变仪无法表征这三种加工助剂对HDPE的降黏作用;用Haake流变仪测试表明,加入1 000μg/g加工助剂就能明显降低HDPE在挤出过程中的加工扭矩,进而降低能耗,提高机器寿命和生产效率;极性低聚物和有机硅化合物降低HDPE扭矩的机理和含氟聚合物不同,是内外润滑作用相结合的复合效果。

The authors studied the influences and their action mechanism of three plastics processing aids(PPAs), polar oligomers,fluoropolymers and silicone compounds,on the rheological properties of high density polyethylene(HDPE) by means of melt flow rate meter,capillary rheometer and Haake rheometer.The results indicate that the melt flow rate meter and capillary rheometer are incapable to demonstrate the PPAs' function in viscosity reduction of HDPE.The test by Haake rheometer shows that adding 1 000μg/g of PPAs can markedly decreases the torque during extrusion process of HDPE,thereby being able to reduce energy consumption and raise service life and production efficiency of the extruder.The polar oligomers and silicone compounds have an action mechanism different from fluoropolymers,which is a consequence resulted from the combination of internal and external lubrication of the formers.