模拟酸雨对聚氯乙烯农膜中增塑剂析出的影响

选取某种聚氯乙烯(PVC)农膜进行测试,分析其中所含增塑剂种类以及在模拟酸雨浸泡下增塑剂的析出特性。结果表明,该农膜中添加的增塑剂为邻苯二甲酸-2-乙基己基酯(DEHP),在模拟酸雨浸泡下PVC膜中析出的物质主要为DEHP。当溶液pH值为6.5和5.6弱酸性时,PVC膜析出的DEHP量相对最大,在30d内分别减少了2.66%和2.38%。而当pH值为7.0和2.5时,PVC膜析出的DEHP量中等(30d分别为1.46%和1.52%),当溶液pH值为3.0和4.0时,PVC膜中DEHP的含量水平在30d内只降低了1.33%和1.22%。研究发现,在pH值为5.6和6.5弱酸性酸雨模拟液中,DEHP易于在溶液中分散和降解,并可使PVC膜表面产生一定程度的龟裂,利于PVC膜中DEHP析出。

Effect of Simulated Acid Rain on Release of Plasticizer in PVC Film

One kind of PVC was selected to investigate the effect of simulated acid rain on the release of plasticizer in the film.The results showed that the plasticizer was di-(2-ethylhexyl) phthalate(DEHP) and the released material mainly was DEHP in PVC film under simulated acid rain treatment.When the pH value of acid rain solution was 6.5 and 5.6,the released amount of DEHP reached a peak at 30 day treatment(about 2.66% and 2.38%).The released amount of DEHP was moderate solutions with pH 7.0 and 2.5(1.46% and 1.52% within 30 days).The reducing rates of DEHP remained the least at pH 3.0 and 4.0 solutions(about 1.33% and 1.22% within 30 days).DEHP was easy to disperse and degrade in weak acid solutions and PVC was prone to have crevice on its surface.The solutions of pH 5.6 and 6.5 made DEHP easy to release from PVC films.