The degree of equilibrium crystallinity of Ln-PB is independent of molecular weight at Mη greater than 106, also the linearity is shown between the correspondent temperature, degree of equilibrium crystallinity and molecular weight.
From the semi-crystalline time(t_(1/2))and Avrami exponents(k and n) at differentconditions, and the equilibrium crystallinity(f_∞)at different conditions by density gradient obtained in this paper, the maximumcrystallization temperature (Tc, max)for HDPE was estimated, thereafter, the mechanism of isothermal crystallization ofHDPE, the effects of temperature and nucleating agents on crystallization speed and equilibrium crystallinity were discussed.
The effects of molecular weight and temperature on crystallization processes at low temperature for cis-l,4-polybutadine prepared with rare-earth catalyst (Ln-PB) have been studied by WAXD method. In the range of molecular weight from Mη≈2.13× 105 to 46.8×105 there are a maximum of crystallization rate at Mη≈29 × 105 and a minimum at Mη≈8×105. The temperature related to maximum crystallization rate, Tc, max is observed to be between -60℃ and -70℃. The degree of equilibrium crystallinity of Ln-PB...
The kinetics of isothermal crystallization of HDPE at 55~120℃ and when 4 nucleating agents were added at 90℃ wasinvestigated by the method of dilatometry. From the semi-crystalline time(t_(1/2))and Avrami exponents(k and n) at differentconditions, and the equilibrium crystallinity(f_∞)at different conditions by density gradient obtained in this paper, the maximumcrystallization temperature (Tc, max)for HDPE was estimated, thereafter, the mechanism of isothermal crystallization ofHDPE, the effect...