高分子複合材料的的機械性質好壞，除了材料本身的性質之外，尚取決於強化材與基材的界面能量，對於加工的條件有很大的影響，而接觸角(contact angle)與表面張力(surface tension)是獲得界面性質的重要因素，此外在複合材料加工過程中，樹脂浸潤纖維的行為，亦受其界面張力的影響。 本研究的系統，是熱固型樹脂環氧樹脂添加反應性官能基液態橡膠CTBN。環氧樹脂添加橡膠的目的，在於改進其易脆性質。一般對於環氧樹脂添加橡膠的研究大都偏向機械性質，或是固化後的物性與型態學探討，對於反應過程中的物性及界面能量變化卻鮮少報導。我們藉由測量接觸角與表面張力的方法，來探討在環氧樹脂添加液態橡膠CTBN在交聯硬化的過程中，液態CTBN橡膠對界面性質的影響。經過FT-IR的觀察，求得硬化過程中一級胺基與環氧基的變化情形與分子量的變化，並找出其表面張力與碳纖界面能量的關係，結果發現隨聚合反應進行，密度和表面張力均會降低，而與碳纖界面張力則會上升。另一方面，橡膠添加會降低樹脂密度，表面張力，以及與碳纖的界面張力。同時也可從FT-TR獲得橡膠的分布狀況，結果顯示橡膠分子在表面會有較高的濃度，這也導致了與碳纖界面能量的變化；由於反應過程中的界面能量等物性不易測得，本研究可提供加工複合材料時反應條件參考。 Performance of composite material is determined largely by the structure and properties of the interface between the matrix and reforcements. In this work, we investigated the history of the surface tensions of the liquid rubber filled epoxy resin during cure. The variations of the interfacial energy between epoxy and carbon fiber were also observed indirectly through the measurement of contact angles. Our result shows that surface tension decreases with the advancement of the curing reaction. On the other hand, the solid/liquid interfacial energy increases with the reaction. The former drops significantly during the gelation process; the latter, however, is more sensitive to the dissolution of rubber from resin. The phenomena of phase-inversion, in which case rubber-rich phase becomes continuous, can also be identified easily by these measurement.
