乙烯-乙烯醇共聚物性能及共混改性研究

Study on the performances of ethylene-ethenol copolymer and its blending modification

研究了乙烯-乙烯醇共聚物(EVOH)的热熔融性能、物理机械性能以及加工流变性能。结果表明,EVOH为结晶性材料,于198℃时完全熔融,在200℃左右可以进行熔融加工;EVOH的拉伸强度和弹性模量都很高,而断裂伸长率却较低,表明其作为厚制品时是一种刚性较好的材料;EVOH为假塑性非牛顿流体,其黏度对温度的变化比较敏感,属温敏性材料;EVOH在挤出加工时,挤出机各段加热温度应有较佳分布,同时要合理控制挤出速率;用EVOH改性高密度聚乙烯(HDPE)时,可以显著提高共混物的拉伸强度;用HDPE改性EVOH时,随HDPE加入量增大,共混物的挤出主机电流下降,说明材料的熔体黏度下降,挤出机负荷降低,共混物的加工流变性得到改善。

The melting,physical mechanical and the rheological properties of ethylene-ethenol(EVOH) were studied.The results showed that EVOH was a kind of crystalline material.It was melted completely at 198()℃ and could be processed at 200()℃.The tensile strength and elastic modulus of EVOH was high,but its elongation at break was rather low,which indicated that EVOH was a rigid material as thick articles.Rheological behavour reaserch showed that EVOH was a non-Newtonian fluid and its apparent viscosity was sensitive to temperature.When EVOH was processed by extruder,the extruding rate and the temperature of extruder zones should be well-controlled.EVOH could modify the tensile strength and barrier properties of high density polyethylene(HDPE) evidently,and HDPE could modify the processing properties of EVOH.The extruder current of blending declined as the(amounts) of HDPE increasing,it showed that the apparent viscosity of the blends reduced,and so was the load of the extruder.