聚丙烯接枝乙烯醇结晶性能的研究

用DSC研究了PP，PP-g-VAc和两种不同醇解率PP-g-VOH的非等温结晶行为，以Reziorny修正的Avrami方程进行了动力学分析，用偏光显微镜观察了接枝物球晶形态的变化。研究结果表明：VOH接枝链可以有效地促进PP异相成核，导致Avrami指数n随醇解率增加而降低，结晶温度显著增加，结晶热焓增加；同时，由于VOH引入支链，降低了分子链的规整性，限制了PP排入晶格的速率，致使半结晶时间t_1/2和结晶速率Z_c常数降低。试样的偏光显微镜观察表明，PP-g-VAc的醇解率增加，球晶数目增多，直径减小，完善程度降低。

Crystallization properties of PP-g-VOH

The crystallization behaviors of PP, PP-g-VAc and PP-g-VOH with different saponification percentages (PS) were studied by the differential scanning calorimetry (DSC) and the crystallization kinetics under nonisothermal conditions were analyzed by Jeziorny method. The morphologies of spherulite of the samples were inspected by a polarizing microscope. The results showed the grafting of VOH could accelerating the nucleation rate of PP effectively, which led to decrease in Avrami exponent n and increase in crystallization temperature Tc and enthalpy ΔH. Simultaneously, because the macromolecular regularity was decreased, the crystallization half time t_1/2and crystallization rate constant Z_c of PP-g-VOH were decreased. Micrographs of the crystal showed the number of spheruliteincreased markedly, but the diameter and integrity of crystal decreased with the increase in P_S.