發泡射出成型製程中泡體尺寸、密度及分布的控制是非常複雜，特別是在高減重比情況下更容易出現泡體尺寸分布不均及泡體破裂等缺陷，這些缺陷進而影響到產品之機械性能。
本研究利用奈米碳管添加至兩種不同材料分別為熱塑性聚氨酯(TPU)及聚丙烯(PP)，再使用氣體反壓技術(Gas Counter Pressure, GCP)改善泡體結構。透過SEM截面圖、泡體直徑、泡體密度、泡體尺寸分布探討奈米碳管含量、SCF含量、反壓壓力及持壓時間對於泡體結構變化之影響。研究結果表示兩種材料均在添加奈米碳管後平均泡體尺寸下降，TPU之平均泡體直徑約下降12μm，大於100μm之泡體占比由8.18%降低至3.64%，PP之平均泡體直徑約下降60μm，大於100μm之泡體占比由42.6%降低至22.33%，而在使用氣體反壓技術後，TPU平均泡體尺寸降低至32μm，且有50%以上之20~40m泡體，PP之平均泡體直徑降低至約67μm，大於100μm泡體占比降低至約15%，達成均勻度之改善。

Foaming injection molding is very difficult to control of the cell size, foam density and distribution of cells size. And the most frequently occurring defects at high weight-loss ratio are non-uniform cells microstructure and cell collapse. Many of the defects in the structure of cell will affect the mechanical properties of the product.
In this study, multi-walled carbon nanotubes(MWCNT) were added in two different materials, one is TPU and another is PP. Subsequently, gas counter pressure technology (GCP) is used to change the cell structure. The cell structure is affected by MWCNT content, SCF content, GCP pressure and GCP holding time were investigate by SEM cross-section, cell diameter, foam density and distribution of cell diameter. The result show that the average cell diameter of TPU decreases 12μm, and the ratio of foams with a cell size over than 100μm decreases from 8.18% to 3.64%. The average cell diameter of PP decreases 60μm, and the ratio of foams with a cell size over than 100μm decreases from 42.6% to 22.33%. Furthermore, After using the GCP, the average cell diameter of TPU decreases to 32μm and 50% of cell diameter can be controlled within 20~40μm. The average cell diameter of PP decreases to 67μm, and the ratio of foams with a cell size over than 100μm decreases to 15%. It’s improve the uniformity of manufacturing.

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