Study of the Morphology in Water-Assisted Injection Molded HDPE/PA6 Parts
| Autor: | Wei Ru Lin, 林蔚儒 |
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| Rok vydání: | 2009 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 Water assisted injection molding has become one of the most important polymer processing methods for making hollowed parts. This study examined the skin-core structure in water assisted injection molded high density polyethylene (HDPE)/polyamide-6 (PA-6) blends. Samples for microscopic observation were prepared by an 80-ton injection-molding machine equipped with a tube cavity and with a water injection unit. A distinct skin layer, core region, and channel layer were observed across the thickness. The shape and size of the dispersed phase depended on the position both across the part thickness and along the flow direction. Small and large particles coexisted in the skin and channel layers, indicating that both coalescence and breakup of the dispersed phase occurred in these layers. High water pressures were found to mold parts with smaller PA particle distribution. Additionally, the structural development in water assisted injection molded parts was compared to that in gas assisted injection molded products. It was found that water molded parts with a smaller PA particle distribution than gas. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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