We investigated the spherulite growth rate (G) in a 40/60 isotactic polypropylene (PP)/liquid paraffin (LP) mixture under a polarized microscope with a TV video recording system. The molecular weight of LP (M) was changed. Subtracting the supercooling contribution from the overall G, we obtained the chain mobility (fig) factor, as a function of M and crystallization temperature (To). As T~ increased, a transition from regime III to II was found to occur. An Arrhenius plot of the fig term showed that the activation energy in regime II is much larger than that in regime III, suggesting different diffusion modes. The fig term in regime III was found to depend strongly on M (fls~:M-1), indicating a mutual-diffusion mode. In contrast, the fls term in regime II weakly depends on M, indicating a self-diffusion mode (flg~:M-1/2).
Посилання на статтю:
Kinetics of crystal growth in mixtures of isotactic polypropylene and liquid paraffin / Tetsuo Okada, Hiromu Saito and Takashi Inoue // Polymer. – 1993. – Vol 34. – P. 4752-4755.