Non-isothernial crystallization kinetics and morphology of isotactic polypropylene (iPP) nucleated with rosin-based nucleating agents

The non-isothermal crystallization kinetics of iPP with 0.3 wt.% of nucleating agent potassium dehydroabietate (DHAA-K) or sodium dehydroabietate (DHAA-Na) at different cooling rates was investigated using a differential scanning calorimetry technique together with Jeziorny's, Mo's, and Caze-Chuah's methods. The results indicated that all three models gave good fitting to experimental data. The Avrami exponents of crystallization for iPP, PP-K, and PP-Na were about 3, 2, and 2, respectively, suggesting a change of crystal growth mechanism for the nucleated iPP. The activation energies of the crystallization, estimated with Kissinger's method, increased in magnitude for the nucleated iPP compared with W. Moreover, the results of PLM and SEM showed that detectable spherulites were suppressed by the nucleating agents.