We investigated the spherulite growth rate G in 60/40 isotactic polystyrene (i-PS)/atactic polystyrene (a-PS) mixtures under a polarized microscope with a TV video recording system. When the molecular weight M A of a-PS was higher than 1.91 x 104, linear growth was observed, i.e. G was constant throughout the crystallization, and the chain diffusivity D T decreased monotonously with increasing M A. In contrast, when M A was less than 5.2 x 10 3, the growth was non-linear, i.e. G decreased with time, and D T increased with increasing M A (DTOCM~/2). Both M A dependences on D T were successfully interpreted using a modified Hoffman-Lauritzen theory involving the exclusion effect of a-PS. On the basis of this modified Hoffman- Lauritzen theory, the spherulite growth mode, i.e. linear or non-linear, was also interpreted in terms of a new kinetic parameter 2 = D~JD,, D* and D s being the tracer diffusion coefficient of a-PS and the self-diffusion coefficient of i-PS, respectively.
Посилання на статтю:
Kinetic studies of crystallization in mixtures of isotactic polystyrene and atactic polystyrene / Tetsuo Okada, Hiromu Saito and Takashi Inoue // Polymer. – 1994. – Vol 35. – P. 5699-5705.