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采用有限元法,数值模拟了成型过程中镍制模具和PVC材料的非稳态温度场,进而得到了PVC材料结构参数的时间演变和空间分布规律,再由结构-性能关系获得了PVC材料的溶胶黏度及其演变特点,在此基础上比较分析了不同增塑剂对PVC材料物理凝胶化转变过程的影响.结果表明,由于热阻不同,靠近模具壁的PVC溶胶升温速率较大,首先发生凝胶化转变;加热过程中,PVC材料的黏度首先降低至最小值,凝胶化转变开始后,PVC树脂和增塑剂之间的相互作用增强,材料黏度迅速升高;不同增塑剂对材料结构参数和溶胶黏度的演变规律有着不同影响.
The finite element method was used to numerically simulate the unsteady temperature field of the nickel mold and PVC during the forming process. The time evolution and spatial distribution of the structural parameters of the PVC material were obtained. Then the structure and properties of the PVC material Sol-gel viscosity and its evolution characteristics were analyzed based on which the effect of different plasticizers on the physical gelation process of PVC was analyzed. The results show that due to the different thermal resistances, PVC sol near the mold wall has a higher heating rate. The gelation changes. During the heating process, the viscosity of the PVC material is reduced to the minimum first. After the gelation transformation begins, the interaction between the PVC resin and the plasticizer increases and the viscosity of the material increases rapidly. Different plasticizers The structural parameters of the material and the evolution of sol viscosity has a different impact.