结构化丙烯酸酯共聚物的制备及在发泡制品中的应用

Proparation of A Structured Acrylic Copolymer and Its Application in Rigid PVC Foam Products

采用种子乳液聚合方法制备了核壳结构丙烯酸酯共聚物[PMMA/Poly(MMA-co-St-co-AN),PMSN]胶乳,其单体转化率高,无二次成核现象,最终乳胶粒粒径可控;随着壳层丙烯酸烯丙酯(AMA)含量的增加,PMSN的特性黏数升高;此时PMSN与聚氯乙烯(PVC)共混物的平衡扭矩明显提高。这对于硬质PVC发泡制品的正常挤出过程是必需的,因为其密度只有普通硬制品的三分之一,这种PMSN加工助剂可防止泡孔的坍塌,满足工业使用条件。

PMMA/Poly（MMA-co-St-co-AN）,PMSN,with core-shell structured copolymer was prepared by seeded emulsion polymerization.The monomer conversion is high and the particle diameter distribution monitored by dynamic light scattering is narrow.This results show that the particles grow without significantly secondary nucleation occurring and the latex particle size can be designed.Meanwhile,the intrinsic viscosity [η] for the soluble polymer of PMSN in butanone increases with the addition of allyl methacrylate （AMA）.When PMSN is blended with low molecular weight poly（vinyl chloride）（PVC） resin,the melt equilibrium torque is increased with the increase of intrinsic viscosity of PMSN.Extrusion of rigid foam is the most demanding PVC process in terms of melt strength.Since the final targeted density can typically be a third of that of compact PVC,high melt strength is essential to retain gas bubbles in the melt and to avoid a collapse of the cells.Finally,the PMSN process aid synthesized meets the industrial requirements of rigid PVC foam.