碳纖維強化聚苯硫醚複合材料成形品之機械性質評估

Evaluation of Mechanical Properties of Carbon Fiber Reinforced Polyphenylene Sulfide Composite

吳長鴻(Chang-Hung Wu)

指導教授 ： 陳仁浩

國立交通大學/工學院/機械工程系所/碩士(2018年)

摘要

碳纖維強化塑料主要可提供產品輕量化、高強度等優勢，目前廣泛應用於航空工業、汽車工業等各式領域。碳纖強化複材常見應用方式是將碳纖維預浸編織布層層堆疊後熱壓成形，使用時再需依成品輪廓裁切，因此無法快速大量生產為其缺點。至於一般市售射出成形用的碳纖維熱塑性料粒，由於經混煉造粒過程造成纖維斷裂變成短纖維，使強化效果降低。
本研究旨在探討利用粉漿預浸法製作之胚料，經成形後其碳纖維與聚苯硫醚複合後的強度，並進而驗證此工法製作之預浸複材具有易於使用、高強度及低開發成本等優勢。
本研究之試片應用熱壓成形與射出成形兩種方式製作，找出利於材料成形之條件，並藉拉伸、彎曲、衝擊等試驗評估此預浸複材之性能，與市售產品進行比較。另以顯微鏡分析材料內部結構及試驗後之破壞斷面，分析材料結構組成的強化機制。
研究實驗結果顯示，碳纖維含量55 wt%於熱壓成形時，碳纖維會交纏聚集使聚苯硫醚分子不易流動，不利於成形。當材料加熱溫度達310℃以上時，材料間介面接合的狀況能有所改善。射出成形時過高的纖維含量將造成材料流動性低落。預浸複材經成形後，材料拉伸強度提升60 %、彎曲強度提升37 %、抗衝擊強度提升34 %。
碳纖維含量15 wt%之預浸複材成形品的拉伸及抗衝擊強度皆高於市售30 wt%之碳纖維/聚苯硫醚混合料粒者，說明此種預浸胚料的方法有利於維持較長的纖維長度，因此可使用較少碳纖維量，達到較高的強度。預浸複材隨著碳纖維含量的增加，整體保留的纖維長度有下降之趨勢，但各項機械性質因碳纖維含量增加而有明顯的上升。

關鍵字

碳纖維 ； 聚苯硫醚 ； 複合材料 ； 射出成形

並列摘要

Carbon fiber-reinforced polymer (CFRP) composites can provide ad-vantages such as being lightweight and high strength and are currently widely used in various fields such as in the aviation and automobile industries. A common application method of carbon fiber reinforced composites is to hot-press them and form carbon fiber prepreg woven fabrics after they are stacked. However, the cutting of these fabrics according to product contours cannot be quickly mass-produced. The fibers of carbon fiber thermoplastic granules, which are commercially available for injection molding, tend to break into short segments due to the mixed granulation process., reducing the strengthening effect.
The purpose of this study is to investigate the strength of composites pre-pared via the slurry prepreg method and to verify that prepreg composites produced using this method are easy to use in processing and have high strength and low developmental costs.
In this study, test specimens are prepared via hot-press forming and injec-tion molding processes. We identify the conditions conducive to their formation and evaluate the properties of the prepreg composites via tests, such as stretch-ing, bending, and impact, compared to commercially available CF/PPS gran-ules. In addition, the internal structure of the material and the fracture surface after the tests are analyzed via microscopy to determine the strengthening mechanism of the material structure.
The results show that when the carbon fiber content is 55 wt% in the hot-press forming process, the carbon fibers intertwine so that the PPS mole-cules do not flow easily into forms. When the material heating temperature is above 310°C, the interface between the materials can be improved. Excessive fiber content during injection molding will result in a low fluidity of the mate-rial. After the prepreg composites were tested, the tensile strength increased by 60 %, the bending strength increased by 37 %, and the impact strength increased by 34 %.
The tensile strength and impact strength of the prepreg composites with a carbon fiber content of 15 wt% are higher than those of the commercially available 30 wt% CF/PPS mixing granules, which means that prepreg compo-sites via the slurry prepreg method require less carbon fiber to achieve the higher strength, and maintain the longer fiber length. With increasing carbon fiber content, the fiber lengths of the prepreg composite material have a tendency to decrease but their mechanical properties increase significantly due to the increase in their carbon fiber content.

並列關鍵字

Carbon fiber reinforced polymer ； Composites ； Polyphenylene sulfide

參考文獻

[1] Soutis, C., 2005, "Carbon fiber reinforced plastics in aircraft construction," Materials Science and Engineering: A, 412(1), pp. 171-176.

[2] Friedrich, K., and A. Almajid, A., 2012, Manufacturing Aspects of Advanced Polymer Composites for Automotive Applications.

[3] May 2016, " Global Carbon Fiber Composite Market," Acmite Market Intel-ligence.

[4] Todo, M., Nakamura, T., and Takahashi, K., 2000, "Effects of Moisture Ab-sorption on the Dynamic Interlaminar Fracture Toughness of Carbon/Epoxy Composites," Journal of Composite Materials, 34(8), pp. 630-648.

[5] Nakamura, T., Singh, R. P., and Vaddadi, P., 2006, "Effects of Environmental Degradation on Flexural Failure Strength of Fiber Reinforced Composites," Ex-perimental Mechanics, 46(2), pp. 257-268.