Determination of crystallization kinetics parameters under high pressure using PvT data
Ito Hiroshi; Takahara Masahiro; Takimoto Jun-ichi; Koyama Kiyohito
Abstract:A new method has been proposed to determine directly the temperature dependence of the nucleus number N and the linear growth rate G of spherulite under high pressure directly from PvT data. The PvT measurements of polypropylene were carried out for isothermal crystallization at 170 degree, 165 degree and 160 degree under 100MPa, and the temporal variation of the crystallinity xc(t) was obtained from the PvT data. The crystallization parameters N and G were determined so that the xc(t) calculated from the parameters agreed most well with that determined from the PvT data. The simulation of isothermal crystallization by using the determined parameters agreed very well with the experimental PvT data. PvT measurements for non-isothermal crystallization were also carried out at constant cooling rates of -1 and -0.25 degree/min under 100MPa. The simulation of this non-isothermal crystallization also agreed well with the experiment, except for slight overestimate of the crystallization temperature which may be due to the inhomogeneity of temperature within the sample. Key Words:linear growth rate, nucleus number, kinetics parameter, PvT measurement, crystalinity, computer simulation