EVA增韧改性聚氯乙烯合金的制备和性能

Preparation and properties of PVC Alloy Toughened by EVA

选择三种不同醋酸乙烯酯(VAc)含量的EVA,采用熔融共混和接枝共聚方法制备增初改性PVC合金,考察EV A结构和合金制备方法对合金力学性能的影响。随着EVA添加量的增加,熔融共混制备的VAc含量为15%(质量分数,下同)的EVA/PVC合金的抗冲强度先缓慢增加、接着快速上升、再缓慢增大的变化趋势,而V A c含量为20%和25%的EVA改性的PVC合金的抗冲强度则先增加后降低;EVA的加入使合金的拉伸强度降低,加入高VAc含量的EVA,下降更明显。相同EV A添加量时,采用接枝共聚制备的PVC/EVA合金的抗冲强度远大于熔融共混制备的PVC/EVA合金,断面呈现典型的韧性断裂形貌。

EVA with different vinyl acetate(VAc)contents were used to prepare toughened PVC alloys through melt-blending and grafting copolymerization approaches.Effects of EVA structure and preparing method of alloys on the mechanical properties were investigated.When EVA with 15%content of VAc was used,the impact strength of PVC/EVA alloys was increased slightly at low EVA usage,increased rapidly at 4%~8%usage,and increased slightly as EVA usage exceeded 8%.For EVA with 20%and 25%contents of VAc,the impact strength of PVC/EVA alloys were firstly increased and then decreased as EVA usage increased.The tensile strengths of PVC/EVA alloys were decreased as EVA usage increased,especially for EVA with higher VAc content.PVC/EVA alloys prepared by grafting copolymerizations exhibited greater impact strengths than PVC/EVA alloys prepared by melt-blending at the same EVA usage.