Stereocomplex Crystallization of Star‐Shaped 4‐Armed Equimolar Stereo Diblock Poly(lactide)s with Different Molecular Weights: Isothermal Crystallization from the Melt
Department of Environmental and Life Sciences, Graduate School of Engineering, Toyohashi University of Technology, Tempaku‐cho, Toyohashi, Aichi, Japan
Abstract:
The isothermal crystallization of star‐shaped four‐armed equimolar stereo diblock poly(lactide) (4‐LD) polymers with different molecular weights is investigated. Solely stereocomplex (SC) crystallites are formed in all equimolar 4‐LD polymers, irrespective of molecular weight and crystallization temperature (Tc). The wide‐angle X‐ray diffractometry, differential scanning calorimetry, and polarized optical microscopy results for crystalline species, crystallinity, and maximum radial growth rate of spherulites values indicate that both branching and diblock architectures disturb the SC crystallization and spherulites growth of equimolar 4‐LD polymers, and the disturbance effect is larger for branching architecture than for diblock architecture. The equilibrium melting temperature (Tm0) values are 181.9–266.0 °C, which are comparable with or lower than the value reported earlier (279 °C). The crystallite growth geometries of equimolar of 4‐LD polymers are independent of molecular weight and Tc.
