偏氯乙烯共聚物颗粒发泡能力的影响因素

以1-氟-1，1-二氯乙烷(HCFC-141b)作发泡剂，研究了偏氯乙烯(VDC)共聚物颗粒的发泡能力、中空颗粒的泡孔结构及发泡倍率。实验发现，VDC-甲基丙烯酸甲酯(MMA)共聚物的发泡能力较强，而VDC-丙烯腈(AN)共聚物颗粒很难发泡，当引入第三单元苯乙烯(St)后可改善其发泡性能。VDC—AN—St共聚物颗粒的发泡倍率随着发泡剂浓度的增加或发泡温度的提高而先增加后减小，气泡将随着发泡温度的提高而最终全部破裂塌陷。由破泡和扩散造成的发泡剂损失对VDC共聚物颗粒发泡能力的影响已不能忽略。

STUDY ON THE FOAMABILITY OF VINYLIDENE CHLORIDE COPOLYMER PARTICLES

The foamability of vinylidene chloride(VDC)-acylonitrile(AN), VDC-methyl methacrylate (MMA), VDC-AN-styrene(St) copolymers particles were investigated with 1-fluoro-1,1-dichloroethane (HCFC-141b) as blowing agent. It was found that VDC-MMA copolymer particles with high MMA content are expandable but VDC-AN copolymer particles are not at any AN content. Addition of St unit in VDC-AN copolymer can improve its foamability. Low bubble density and breakage of bubble were observed for VDC-AN-St terpolymer particles at high HCFC-141b content or at high temperature. The expanding ratio of VDC-AN-St terpolymer particles increases firstly with HCFC-141b content or temperature, and then decreases. The observed expanding ratios are much smaller than the theoretical one, indicating that loss of blowing agent created by breakage of bubble and/or diffusion of blowing agent to the surrounding can't be neglected for the expansion of VDC-AN-St terpolymer particles.