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本文研究了三种不同厚度的PET薄膜在四种不同温度条件下进行真空固相缩聚的规律,得出的结论是:在160℃和180℃这样较低的温度下符合二级动力学方程,化学反应是控制步骤;在210℃和230℃这样较高的温度条件下遵从扩散方程,扩散是控制步骤。本论文着重研究了扩散控制条件下的反应规律,以扩散模型为出发点,建立了一个计算机程序,计算出了平衡分子量和小分子副产物的扩散系数。平衡分子量和扩散系数均因预聚体的结构和反应温度不同而异。还计算了理论曲线和扩散活化能,所得理论曲线与实验规律符合得较好,算出的扩散活化能为5.89Kcal/mol(1.0mm膜)和5.21Kcal/mol(0.1mm膜)。
In this paper, the vacuum solid phase polycondensation of PET films with three different thicknesses under four different temperature conditions was studied. The conclusion was reached that the second-order kinetic equation was satisfied at the lower temperature of 160 ℃ and 180 ℃, The chemical reaction is the control step; the diffusion equation follows the higher temperature conditions of 210 ° C and 230 ° C and diffusion is the control step. This thesis focuses on the reaction rules under diffusion control conditions. Based on the diffusion model, a computer program is established to calculate the equilibrium molecular weight and the diffusion coefficient of small molecule by-products. Both the equilibrium molecular weight and the diffusion coefficient vary depending on the structure of the prepolymer and the reaction temperature. Theoretical curves and diffusion activation energies were also calculated. The theoretical curves obtained are in good agreement with experimental data. The calculated diffusion activation energies are 5.89 Kcal / mol (1.0 mm membrane) and 5.21 Kcal / mol (0.1 mm membrane).