Nonisothermal Crystallization Process Of The Monte Carlo Simulation

The non-isothermal crystallization process of polymer was simulated by using the Monte Carlo method. The results of the simulating experiment were analyzed by using the Ozawa equation, the modified Ozawa equation, the Jeziorny method, method of the combination of the Ozawa equation and the Avrami equation, and the iso-conversional method. The application of previous equation and the method were evaluated, and the conclusions were obtained respectively.Firstly, the computer simulating model of non-isothermal crystallization of polymer was established. The curves of the degree of crystallinity versus time were obtained. And compared with the results of DSC. By adjusting the starting value, the crystallinity curve obtained was close to the experimental one. So the initial temperature and the numbers of nuclei were confirmed by the previous method.The results of the simulating experiment were analyzed by using the Ozawa equation. The obtained values of the Avrami exponent n were smaller than 3. The linear growth rate obtained by the modified Ozawa method was in agreement with the real linear growth rate. However, with the decreasing of the temperature, the values of the experiment one were departed from the values of the theory one. The values of Avrami exponent n obtained by the Jeziomy method were far larger than 3 and the crystallization rate constant didn't remain a constant. The crystallization rate constant K, the activation energy of crystallizing Ed, the nucleation parameter ψ obtained by the iso-conversional method was close to the real ones. But there was a discrepancy in the value of the liner growth rate G. G adopted in the simulating experiment was about 10^-1, whereas the G obtained by the iso-conversional method were all at 10^-4.It was shown that under condition of the predetermined nucleation and the irregular distribution of the nuclei, the Ozawa equation and the modified Ozawa equation were applicable in obtaining the kinetics parameters. It was shown that the Jeziomy method was unsuitable on the non-isothermal crystallization of polymers. The iso-conversional method was suitable to analyze at the crystallization rate constant K, the activation energy of crystallizing Ed, the nucleation parameter ψ, and was unsuitable to analyze the liner growth rate G.