探討二氧化矽在玻璃纖維/環氧樹脂奈米複合材料上對於機械性質所造成的影響

Abstract

本研究主要探討奈米級二氧化矽與橡膠在玻璃纖維/環氧樹脂中對於機械性質所造成之影響。探討奈米級二氧化矽對於剪應力、靜態/動態壓縮強度之影響，以及利用積層間破壞韌性探討橡膠所造成之影響。藉由溶膠-凝膠技術將粒徑為25奈米之二氧化矽均勻分散於環氧樹脂當中，利用手工積層方式將二氧化矽之基材均勻塗佈於等向性之玻璃纖維布上並佐以真空成形，製成玻璃纖維/環氧樹脂奈米複合材料平板。 利用纖維偏軸10°以進行剪應力拉伸實驗以及纖維偏軸0°、5°、10°、15°及90°進行靜態/動態壓縮實驗，油壓式萬能拉伸實驗機(MTS)負責靜態(Quasi-Static)方面的壓縮測試，另外霍普金森桿(SHPB)則在動態(Dynamic)壓縮實驗上作量測。由結果發現添加奈米級二氧化矽於複合材料後其剪應力及壓縮強度皆有達到增益效果，並由電子顯微鏡(SEM)拍攝之圖片得知，添加二氧化矽有助於增強纖維與基材之間的附著力而使機械性質提升。 利用模態一破壞韌性分別探討添加二氧化矽及橡膠對於複合材料之破壞韌性所造成之影響。其中橡膠CTBN和CSR將於本節中進行討論，由實驗結果得知添加橡膠CSR後其破壞韌性提升比例最明顯，進一步添加二氧化矽於橡膠CSR後卻造成破壞韌性下降。然而添加橡膠CTBN後其破壞韌性提升比例較低，接著將二氧化矽混合於橡膠CTBN後對於破壞韌性有提升效果。無論此組合是否採用，添加奈米級二氧化矽與橡膠之混合方式有助於提升複合材料之破壞韌性，並且不影響複合材料之剛性。

The research is aimed to investigate the effect of silica nanoparticles and rubber particles on the glass fiber/epoxy nanocomposites. For the silica nanoparticles, we are focusing on their influence in in-plane shear strength, compression strength. On the other hand, for the rubber particles, the interlaminar fracture toughness is mainly of concern. Through a sol-gel technique, the silica particles with a diameter of 25 nm were exfoliated uniformly into the epoxy resin. The corresponding glass/epoxy nanocomposites were prepared by impregnating the silica epoxy mixture into the dry glass fiber through a vacuum hand lay-up process. The in-plane shear strength was determined from the off-axis 10 degree specimens and the quasi-static and dynamic compressive strengths of glass fiber composite with fiber orientations of 0°, 5°, 10°, 15° and 90° were evaluated from hydraulic MTS machine and Split Hopkinson Pressure Bar (SHPB) respectively. Results indicated that the fiber composites with silica modified epoxy matrix illustrate superior in-plane strength and compressive strength than those without including any silica nanoparticles. Moreover, from SEM micrographics, it was revealed that the enhancement can be attributed the improved interfacial bonding caused by the silica nanoparticles. The dependence of interlaminar fracture toughness of the fiber composites on silica nanoparticle and rubber particles was investigated from double cantilever beam specimens. Both CTBN and CSR rubber particles were considered in the study. Experimental results indicated that the samples with only CSR rubber particles exhibit the highest fracture toughness than other cases. In such case, the contribution of silica nanoparticle demonstrates the diminishing effect on the fracture toughness. However, for the fiber composites with CTBN particles, although their fracture toughness is a little lower, the influence of the silica nanoparticle on the fracture toughness is positive. No matter which ingredients were adopted, the combination of the silica nanoparticles and rubber particle can significantly improve the fracture toughness of the fiber composites without sacrificing their stiffness.