聚丙烯接枝交联物的结晶行为

CRYSTALLIZATION BEHAVIOR OF CROSS-LINKED GRAFTS OF POLYPROPYLENE

以马来酸酐(MAH)和三烯丙基异氰脲酸酯(TAIC)固相法接枝等规聚丙烯(iPP)制备了高接枝率、高极性的PP接枝交联物,并研究了接枝物的流变特性、结晶与熔融行为和结晶形态。在接枝链上引入TAIC后稳定了分子结构,熔体流动速率减小。接枝物的结晶峰温、熔融峰温、结晶度及结晶速度均低于纯PP。但是较高接枝率的交联物的成核作用很强,其等温结晶行为不同于PP和MPP,成核和生长方式为瞬时成核的二维晶粒生长。

The cross-linked grafts of polypropylene with high grafting levels and polarity were prepared from isotactic polypropylene (iPP) reacting with maleic anhydride (MAH) and triallyl isocyanurate (TAIC) in solid phase. Rheological characteristic, crystallization and melting behavior, and crystal morphology of the grafts were studied. Addition of TAIC during reaction makes the molecular structure of PP stable and the molten viscosity increases significantly. The crystallization peaks, melt temperatures, crystallinity and crystallization rates of the grafted PP are lower compared to pure PP. But the nucleating ability of the cross-linked graft with higher grafting level is strongest, and the behavior of isothermal crystallization is different from that of PP and MPP. Its nucleation and growth mechanism is two-dimensional growth of crystallites from instantaneous nucleation.