二氧化矽顆粒對奈米複合材料機械行為之影響

Abstract

本研究主要探討不同比重二氧化矽含量對環氧樹脂基材在機械性質上影響，機械測試性質探討包括拉伸、彎曲及破壞韌性實驗在不同二氧化矽含量下測試。此外，二氧化矽顆粒在延性基材及脆性基材影響都會在本文討論範圍之內。二氧化矽在奈米複合材料分散性利用穿透式電子顯微鏡(TEM)進行探討，結果顯示二氧化矽在奈米複合材料有良好分散性，即使二氧化矽含量達到40wt%。分散優越之二氧化矽顆粒對於增強奈米複合材料機械性質是一大關鍵，尤其是在破壞韌性及揚氏模數方面。場發射電子顯微鏡(FESEM)觀測試片破壞表面，指出二氧化矽與基材界面間有良好的附著力。另外，在奈米複合材料破壞韌性增強的表現可由破壞表面粗糙現象得知，此現象是由於二氧化矽顆粒導致裂紋初始位置裂紋生長受到阻抗，且隨二氧化矽顆粒含量增加其破壞表面粗糙度變得更劇烈，劇烈的破壞表面粗糙度現象可以藉由原子力顯微鏡(AFM)量測。

This research aims to investigate silica particle effect on mechanical behaviors of epoxy matrix. Mechanical tests including tensile, flexure and fracture toughness experiments were conducted on the sample with different silica loadings. Moreover, both ductile and brittle epoxy matrix systems were also discussed in this study. The extension of silica dispersion in nanocomposites was determined using Transmission electron microscope (TEM) based on which it reveals that silica exhibits good dispersion within the nanocomposites even though the silica loading is up to 40 wt%. The exfoliated silica particles may play a major role on the improved mechanical properties of nanocomposites especially for fracture toughness as well as the Young’s modulus. The observation on the failure surfaces using a filed emission scanning electron microscopy (SEM) indicates that the interfaces between silica and matrix are well bonded. In addition, the enhanced fracture toughness in the nanocomposites could be due to the rough fracture surfaces caused by the presence of silica particles complicating the crack initiation. The surfaces roughness becomes more severe as the silica particle loadings increase, which can be qualitatively measured using AFM.