聚乙烯蜡和硬脂酸钙在聚氯乙烯中的压析特性与机理

采用转矩流变仪颜色转移法,测试了聚乙烯蜡A-C 617A及硬脂酸钙(Ca St2)在硬质聚氯乙烯(PVC)中的压析性。结果表明,A-C 617A和Ca St2均产生压析,当用量为1份时,Ca St2的压析性为9. 3级,而A-C 617A的压析性为0. 3级,Ca St2的压析性明显大于A-C 617A;两者的压析性呈现显著的对抗效应,0. 6份Ca St2的压析性为5. 5级,并用0. 4份A-C 617A后,减小为0. 3级,并用A-C 617A能够显著减小Ca St2的压析性。可以推测,压析形成机理为:由于A-C 617A和Ca St2的极性小于金属表面,均能铺展润湿金属表面,形成粘附层,进而产生压析,且由于Ca St2的极性更强,其压析性更大;当Ca St2与A-C 617A并用时,由于A-C 617A可以插入Ca St2粘附层的非极性尾-非极性尾界面,分散Ca St2为反胶束并溶解Ca St2,减弱了Ca St2粘附层的凝聚力,从而有效减小了其厚度,因此,压析性明显减小。

Plate-Out Formation Characteristics and Mechanisms of Polyethylene Waw and Calcium Stearate in Poly Vinyl Chloride

The plate-out formation of polyethylene wax A-C 617A and calcium stearate(CaSt2)in rigid poly(vinyl chloride)(PVC)were investigated by a color transfer method using a torque rheometer.It was shown that A-C 617A and CaSt2 both formed plate-out,when the use level was 1phr,the plate-out of CaSt2 was grade 9.3,while that of A-C 617A was grade 6.3,but the plate-out of CaSt2 significantly heavier than A-C 617A;the plate-out of them showed a significant antagonistic effect,the plate-out of 0.6 phr CaSt2 was grade 5.5,while that of 0.6 phr CaSt2 combined with 0.4 phr A-C 617A was grade 0.3,the plate-out of CaSt2 could be reduced obviously when used in combinaton with A-C 617A.It could be speculated that the plate-out formation mechanisms of them were as follows:because they both had the polarity greater than metal surface,they both could spread out on and wet the metal surface to form a adhesive layer,but because CaSt2 had the greater polarity,it formed the heavier plate-out;when CaSt2 was combined with A-C 617A,A-C 617A could weaken effectively the cohesiveness of CaSt2 adhesive layers and reduce their thickness as the result by inserting into the the non-polar tail interfaces in CaSt2 dhesive layers,disperse CaSt2 as reverse micelles and dissolve CaSt2,therefore,the plate-out was cut down obviously.