聚氯乙烯结晶行为研究

STUDY ON CRYSTALLIZATION BEHAVIOR OF POLY(VINYL CHLORIDE)

采用差示扫描量热（ＤＳＣ）法研究了聚氯乙烯（ＰＶＣ）原粉树脂和重结晶试样的结晶性能，结果表明，ＰＶＣ原粉树脂具有１１０～２２０℃的结晶熔融峰，结晶度随聚合温度的下降而线性增加；退火温度、退火时间等热处理条件对ＰＶＣ的重结晶行为有很大影响；在相同热处理条件下，增塑剂ＤＯＰ的加入使树脂的结晶度下降；聚合度越高的树脂，其结晶度越大。

The crystalline properties of original PVC powders and processed samples were studied by DSC. It showed that PVC powders exhibited the crystalline melting endotherm peaks at about 110￣220 ℃ and the degree of crystallinity(XC) could be calculated from the area of the endotherm peaks. The XC of PVC powders increased with decreasing polymerization temperature. For quenched PVC samples, no melting endotherm peaks were detected. The recrystallization rate is increased by heat treatment and the heat treatment conditions, such as annealing temperature and time, affected the recrystallizatin behavior of PVC. The presented results also show that the XC decreases with increasing concentrations of DOP plasticizer in PVC composites. The recrystallization rate and the equilibrium XC of PVC sample increase as molecular weight of PVC increases for the same processing formulation and heat treatment conditions.