标题：Effect of foam processing parameters on bubble nucleation and growth dynamics in high-pressure foam injection molding
作者：Shaayegan, Vahid; Wang, Guilong; Park, Chul B.
作者机构：[Shaayegan, Vahid; Park, Chul B.] Univ Toronto, Dept Mech & Ind Engn, Microcellular Plast Mfg Lab, Toronto, ON M5S 3G8, Canada.; [Wang, Guilong] Sha 更多
通讯作者：Park, Chul B
通讯作者地址：[Park, CB]Univ Toronto, Dept Mech & Ind Engn, Microcellular Plast Mfg Lab, Toronto, ON M5S 3G8, Canada.
来源：CHEMICAL ENGINEERING SCIENCE
关键词：High-pressure foam injection molding; Bubble nucleation; Bubble growth;; Nucleating agent; Satellite bubbles; In-situ visualization
摘要：We used an innovative visualization mold to investigate the effect of foam processing parameters on bubble nucleation and growth. This was also done to uncover the mechanisms responsible for cellular structural development in the high-pressure foam injection molding process. The effects of the injection speed, the injection gate geometry, the blowing agent content, the melt flow rate and the use of talc as a heterogeneous nucleating agent on the formation and dynamics of cell bubbles were all explored. In the high-pressure foam injection molding process with a proper packing pressure, the overall cell density did not change with the injection speed nor with the injection gate resistance. However, the cell density increased significantly with the blowing agent's concentration and with a nucleating agent. We also observed the growth mechanism of the bubbles in a confined mold cavity, and concluded that the bubble growth rate decreased as the cell density increased. In addition, the satelliting phenomenon, i.e. bubble nucleation around the previously nucleated cells, was observed. This was due to the induced stress fluctuations in the surrounding melt, which could eventually affect the final cellular structure. (C) 2016 Elsevier Ltd. All rights reserved.