氣體反壓對於含碳纖維高分子複材射出成型過程纖維配向度及導電度之影響研究

Effect of Gas Counter Pressure on the Carbon Fiber Orientation and the Associated Electrical Conductivity in Injection Molded Polymer

施銘奕(Ming-Yi Shih)

指導教授 ： 陳夏宗

中原大學/工學院/機械工程研究所/博士(2012年)

https://doi.org/10.6840/cycu201200863

摘要

隨著3C產業、運動器材、汽車產業、生物醫療、能源及航太領域高分子複合材料的大量需求，產品研發著重於降低纖維含量與提升產品高機械性、輕量化與高功能性，其中控制複合材料纖維配向與分佈是主要關鍵。
本研究使用氣體反壓法(Gas Counter Pressure, GCP)應用於射出成型製程，進行不同反壓壓力對纖維配向分佈之基礎實驗，並在不同成型參數、持壓時間與不同比例纖維含量(15 wt%CF及30 wt%CF)下，探討對各層間和各個位置之纖維配向角度分佈、配向層度與穿透導電度(Through-Plane Conductivity, TPC)之影響。
研究結果顯示，基礎實驗中反壓壓力愈大，各層間纖維配向層度大小順序為核心層小於剪切層小於表皮層，其各個位置穿透導電度高低順序為遠澆大於中間大於近澆位置，反壓壓力100 bar下，穿透導電度改善率為63 %。
成型參數實驗，氣體反壓下和流速增加，各層間纖維配向層度值以核心層、剪切層與表皮層順序漸增，而穿透導電度隨射出速度增加而降低，各個位置高低順序為遠澆大於中間大於近澆位置，較佳流速為10 cm3/s；氣體反壓下及料溫溫度提高，各層間纖維配向層度值降低，其層度值大小順序為核心層小於剪切層小於表皮層，其穿透導電度隨料溫增加而改善，並在持壓時間下與料溫250 oC，穿透導電度有所提升；氣體反壓下和較佳成型參數，各層間纖維配向層度值與穿透導電度皆有所改善，於反壓壓力100 bar下，比較有/無持壓時間之穿透導電度分別為3.31 S/cm與3.21 S/cm，其改善率分別為7.6 %和6 %。
在不同比例纖維含量之層度分佈結果，15 wt%CF層度值分佈順序為核心層小於剪切層小於表皮層，30 wt%CF層度值分佈順序為核心層小於表皮層小於剪切層。在穿透導電度改善率比較，反壓壓力增加，30 wt%CF改善率愈小，在持壓時間下50 bar及100 bar平均改善率分別為4.8 %和0.3 %，其各個位置影響以50 bar改善較佳，15 wt%CF改善率隨之增加，反壓壓力100 bar與持壓時間下平均改善率為3 %。氣體反壓法應用於射出成型，可有效控制纖維配向進而改善穿透導電度。

關鍵字

穿透導電度 ； 氣體反壓 ； 纖維配向分佈 ； 纖維配向層度

並列摘要

With an increasing demand of polymer composites in the field of 3C, sports equipment, automotive, bio-medical, energy and aerospace, product development has been focusing on to lower the weight and fiber content, to enhance the mechanical strength and functionality. The key of development lies on the control of fiber orientation and distribution.
In this study, Gas Counter Pressure (GCP) was applied in the injection molding process, with varied level of counter pressure, molding parameters(flowing rate, melting temperature), proportion of carbon fiber (CF) content (15, 30wt%) and holding time, to investigate angle of fiber orientation distribution, fiber orientation level (FOL) and through-plane conductivity (TPC) between each layers (core, shear and skin) and various locations (far, center, and near as referred to the entrance of gate).
As for the results, the part of basic experiment showed a growth of FOL in core layer, shear layer and skin layer sequentially with increasing counter pressure, and a decrease of TPC in the order of far, center, and near. In particular, the TPC improved to 62 % with 100 bar counter pressure. The part of molding parameter experiment showed that under fixed counter pressure and increasing flowing rate, FOL increased in the sequence of core, shear and skin; TPC decreased in far, center and near position, and 10 cm3/s was observed as the optimum flowing rate. Under fixed counter pressure and increasing meting temperature, FOL decreased in the sequence of core, shear and skin; TPC improved with higher melting temperature and holding time. With optimum molding parameters and counter pressure, TPC and FOL both improved. For instance, at 100 bar TPC was 3.31 S/cm with holding time, and 3.21 S/cm without holding time, respectively increased to 7.6 % and 6 % as compared to traditional injection molding out of counter pressure.
FOL, with 15 wt% of CF, increased from core, shear to skin; with 30 wt% of CF, FOL increased from core, skin to shear. Polymer with 30 wt% of CF had a decrease in TPC with increasing counter pressure. For example, TPC decreased 4.8 % and 0.3 % with respect to 50 and 100 bar. Various locations showed great improvement at 50 bar. Additionally, polymer with 15 wt% of CF had an increase in TPC with higher pressure, an average increase 3 % at 100 bar. In conclusion, gas counter pressure can improve FOL and TPC when applied to injection molding.

並列關鍵字

Fiber orientation level ； Gas counter pressure ； Fiber orientation distribution ； Through plane conductivity

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