探討熱塑性聚氨酯/多壁奈米碳管複合材料於高減重比下之泡體均勻度於超臨界微細發泡射出成型之研究

Study of Foaming Uniformity of High Weight Reduction with Microcellular Injection Molded TPU/MWCNT Composites

黃大剛(Ta-Kang Huang)

指導教授 ： 陳夏宗

中原大學/工學院/機械工程研究所/碩士(2019年)

https://doi.org/10.6840/cycu201900607

摘要

熱塑性彈性聚氨酯(TPU)為超臨界微細發泡射出成型製程常用的彈性體之一，TPU具有高彈性、耐化學性、低溫下耐曲折性和耐磨性等優越特性，應用領域概括電子、生物醫學、汽車、體育用品等行業，然而TPU應用在鞋底材料上因重量大、硬度高和減震性差等缺點，故利用超臨界微細發泡射出成型製程改善其鞋底重量、回彈性及柔韌性等性質，但在超臨界微細發泡射出成型製程上泡體的密度、尺寸以及分佈的控制是非常複雜且困難，且在高減重比下最常出現的缺陷為泡體破裂而產生之通孔以及泡體尺寸差距甚大導致均勻度降低，諸多泡體結構上之缺陷會進而影響產品之機械性質。
本研究透過添加多壁奈米碳管(MWCNT)以提升TPU材料之熔體黏度和強度，再經由SEM截面圖、泡體平均直徑、發泡密度、泡體直徑標準差以及泡體直徑數量分佈探討多壁奈米碳管含量、熔膠溫度、模具溫度和SCF含量影響之泡體結構變化，找出適合之最佳參數組合，使高減重比下泡體尺寸及均勻度獲得改善。結果顯示添加多壁奈米碳管有助於通孔比例下降，在高減重比65%下泡體尺寸大於100μm之泡體數量比例由7.52%下降至4.46%，產生通孔的比例下降40.69%，且在產品不同位置處泡體直徑標準差由37.48、46.26、53.78μm降至28.34、38.48、38.27μm，達成整體泡體均勻度上升。

關鍵字

熱塑性聚氨酯彈性體 ； 多壁奈米碳管 ； 超臨界微細發泡射出成型 ； 減重比 ； 泡體均勻度

並列摘要

TPU has superior properties such as high elasticity, chemical resistance, resistance to tortuosity at low temperature and wear. Applications include electronics, biomedicine, automotive, sporting goods, etc. However, TPU applications have disadvantages such as heavy weight, high hardness and poor shock absorption on the sole material. Microcellular injection molding process is used to improve the weight, resilience and flexibility of the sole. However, the control of the foam density, cell size and distribution of the cells size on the microcellular injection molding process is very complicated and difficult, and the most frequently occurring defects at high weight-loss ratio are through-holes and non-uniform cells microstructure. Many of the defects in the structure of cells will affect the mechanical properties of the product.
In this study, multi-walled carbon nanotubes (MWCNT) were added to enhance the melt viscosity and melt strength of TPU materials. The cell structure is affected by MWCNT content, melt temperature, mold temperature and SCF content were investigated by SEM cross-section, average cell diameter, foam density, standard deviation of cell diameter and distribution of cell diameter, then find the best combination of parameters to improve the size and uniformity of the cells under high weight-loss ratio. The results show that the addition of MWCNT contributes to a decrease in the ratio of through-holes. The ratio of foams with a cell size over than 100 μm at high weight-loss ratio of 65% decreases from 7.52% to 4.46%. The standard deviation of the cell diameter was reduced from 37.48, 46.26, 53.78 μm to 28.34, 38.48, 38.27 μm, and the overall cell size uniformity was increased.

並列關鍵字

TPU ； MWCNT ； Mucell ； Cell uniformity ； Weight-loss

參考文獻

參考文獻

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