THE INFLUENCE OF COOLING RATE AND MOLD TEMPERATURE ON POLYMERS CRYSTALLIZATION KINETICS IN INJECTION MOLDING

Crystallinity plays a significant role in determining the quality of molded polymeric products. Higher crystallinity yields higher impact strength, while lower crystallinity yields higher water absorption and faster degradation. Therefore, the crystallinity level within a product should be tuned based on the desired outcome. The degree of crystallinity is determined by the crystallization rate, which is influenced by many processing factors such as cooling rate and mold temperature in injection molding. Moreover, there is not much research conducted to numerically investigate crystal size that develops locally in injection molded products and its relation to cooling rate and mold temperature. In this regard, the cooling rate and mold temperature influence in injection molding is investigated numerically to understand their local effect on crystallization rate and crystal size. Cooling rate and mold temperature were found to play a significant role in influencing crystallization kinetics and crystal size. Moreover, crystallinity was found to vary within one product based on the design and the distance between the investigated sample and the gate. The minor crystallinity point was found to be near the gate, and the largest crystal size was found to be at the furthest point away from the gate.