探討奈米粉體及橡膠粉體對纖維加強奈米複合材料機械性質之影響

Abstract

本研究主要探討兩種奈米複合材料的機械性質：環氧樹酯之破壞行為及以此環氧樹 酯為基材之玻璃纖維/樹脂複合材料積層間破壞行為。兩種材料皆佐以奈米二氧化矽顆 粒及橡膠顆粒進行改質。其中，更深入分析二氧化矽與橡膠顆粒的組合效果，對破壞行 為之影響及其本構關係。本研究使用的橡膠顆粒有兩種：端羧基聚丁二烯丙烯腈 （CTBN），以及核殼型橡膠(CSR)。 一般來說，雖然加入橡膠顆粒能提高樹脂聚合物的韌性，但缺點是其剛性會顯著下 降。為了提高環氧樹脂以及纖維複合材料的破裂韌性，同時不失其剛性，本研究提出利 用二氧化矽奈米顆粒與橡膠顆粒，改質環氧樹脂基材，形成混成型奈米複合材料。首先 製作不同比例混合成的環氧樹脂試片，接著進行拉伸測試並計算其楊氏係數。為了確認 提出的假設--橡膠顆粒所造成環氧樹脂剛性下降之現象，能藉由奈米二氧化矽顆粒作有 效地提升，因此利用拉伸實驗測試來驗證。除了拉伸剛性之外，藉由在單邊切口試片 (SENB)上進行三點式彎曲測試，以探討添加奈米二氧化矽顆粒與橡膠顆粒，對環氧樹脂 材料之破壞韌性影響。此外，本研究亦藉由雙懸臂樑試片測量，來探討奈米二氧化矽顆 粒與橡膠顆粒，對玻璃纖維奈米複合材料積層間破壞行為之影響。藉由掃描式電子顯微 鏡(SEM)觀察試片破壞表面，分析並確定其相關破壞機制。最後，根據此破壞機制，定 性地來瞭解奈米二氧化矽顆粒與橡膠顆粒對複合材料之破壞行為之影響。

The research aims to investigate the fracture behavior of epoxy resin as well as the interlaminar fracture toughness of glass fiber/epoxy composites modified with silica nanoparticles and the rubber particles. The combination effects of these two particles on the constitutive response as well as the fracture behavior are especially of concern in the examination. Two kinds of rubber particles were employed to moderate the epoxy resin, one is the reactive liquid rubber (CTBN) and the other is the core-shell rubber (CSR). In general, the disadvantage of adding rubber particles into polymeric resin is the dramatic reduction of stiffness although the toughness could be modified accordingly. In order to enhance the fracture toughness of the epoxy resin as well as the corresponding fiber composites without sacrificing their stiffness, the silica nanoparticles in conjunction with the rubber particles were introduced into the epoxy matrix to form a hybrid nanocomposite. The coupon epoxy specimens were fabricated and then tested in tension to evaluate the corresponding Young’s modulus of epoxy samples with different modifications. The experimental results are quite essential to confirm the presumption that the reduction of the epoxy stiffness caused by the presence of rubber particles can be effectively compensated by the silica nanoparticles. In addition to the tensile stiffness, the influence of silica nanoparticles as well as the rubber particles on the Mode I fracture toughness of bulk epoxy was examined by performing three point bending tests on single edge notched bending (SENB) specimens. Furthermore, the interlaminar fracture behaviors of glass fiber composites modified with silica nanoparticles and rubber particles were measured from the double cantilever beam (DCB) specimens. The corresponding failure mechanism were determined and discussed based on the Scanning Electronic Microscopy (SEM) observation on the fracture surfaces. Finally, the results will be discussed and the influence of the silica nanoparticles and rubber particles on the fracture behaviors of composites will be characterized in accordance with the failure mechanism.