磺化间规聚苯乙烯和间规聚苯乙烯的非等温结晶动力学

对磺化度分别为 1 6 0mol% ,3 0 5mol% ,4 41mol%的磺化间规聚苯乙烯和间规聚苯乙烯的非等温结晶动力学进行了研究 ,用DSC测试了四种样品的非等温结晶过程 ,对所得数据分别用Mandelkern方法和莫志深方法进行了处理 ,发现磺化间规聚苯乙烯和间规聚苯乙烯的非等温结晶动力学参数差别较大 ,说明磺酸基团的引入对sPS结晶行为有较大的影响 ,磺酸基团之间的氢键相互作用使SsPS的结晶速率降低 ,结晶度减小 .此外 ,SsPS和sPS的Avrami指数n值均在 2～ 3之间 ,且为非整数 ,说明它们主要是以混合成核的方式结晶 .SsPS的成核与生长活化能ΔE值高于sPS的 ,并且随磺化度的增加而递增 ,sPS的ΔE值为 2 40 5 0kJ/mol,磺化度为 1 6 0mol% ,3 0 5mol%和 4 41mol%的SsPS的ΔE值分别为 2 5 1 70kJ/mol,2 72 33kJ/mol和2 90 79kJ/mol.

KINETICS OF NONISOTHERMAL CRYSTALLIZATION OF SULFONATED SYNDIOTACTIC POLYSTYRENE AND SYNDIOTACTIC POLYSTYRENE

The kinetics of nonisothermal crystallization has been studied for sulfonated syndiotactic polystyrene (S s PS) containing 1 60mol%,3 05mol% and 4 41mol% sulfo groups,and pure syndiotactic polystyrene ( s PS) by means of differential scanning calorimetry (DSC) at various cooling rates.The theory of Mandelkern and the method of Mo Zhishen for nonisothermal crystallization are used to analyze the DSC data.The results show that the crystallization behavior of S s PS exhibits considerable differences in comparison to the neat sample.The degree of crystallinity and the rate of crystallization are significantly lowered by the presence of sulfo groups.The noninteger Avrami exponents,between 2 and 3,for s PS and S s PS samples during nonisothermal crystallization procedure indicate that a mixture of nucleation and growth mechanisms are occurring.On the other hand,the quite comparable Avrami exponents for the s PS and S s PS samples suggests that sulfonation does not significantly alter the observed crystallization mechanism of s PS.In addition,the crystallization activation energies for nonisothermal crystallization are evaluated to be 240 50kJ/mol for s PS,and 251 70kJ/mol,272 33kJ/mol and 290 79kJ/mol for S s PS containing 1 60mol%,3 05mol% and 4 41mol% sulfo groups,respectively.