研究有機黏土對玻璃纖維材料在層間破壞韌性行為的影嚮

Abstract

本研究目的是利用有機黏土作為加強材，研究環氧樹脂和玻璃纖維/環氧樹脂材料的機械行為。為了確認有機黏土在環氧樹脂中的效應，分別將含有2.5wt%，5.0wt%以及7.5wt%的有機黏土利用超音波震盪的方式將其分散在環氧樹脂□。拉伸試驗和破壞實驗分別用來分析他們的剛性，破壞強度以及破壞行為。從拉伸驗實驗的結果得知，增加5 wt%的有機黏土可以使得環氧樹脂原本的剛性增加了16%的加成效應，但是原有的破壞應變的特性卻減少了。並且使用一具有單邊裂紋的變矩(SENB)試片執行破壞實驗，結果指出有機黏土會使得環氧樹脂的破壞韌性產生劇烈的下降。從電子掃描顯微鏡觀察發現奈米複合材料有轉變成脆性材料的特性。 為了研究有機黏土在玻璃纖維/環氧樹脂複合板材的影嚮，利用5 wt%的有機黏土分在環氧樹脂□，接著使用手積層(hand-lay-up)的方式將之和玻璃維材料製成奈米複合板材。依照偏軸拉伸試驗以及第一類層間的破壞試驗分析奈米複合板材的拉伸強度以及破壞行為。從偏軸拉伸試驗顯示出奈米複合板材比傳的複合板材具有較好的拉伸強度，在另一方面，奈米複合板材的層間破壞韌性卻變差了，這個趨勢和在環氧樹脂的樣本上具有相同的特性。

This study aims to investigate the organoclay effect on the mechanical behaviors of epoxy resin as well as glass fiber/epoxy composites. To understand organoclay effect on the epoxy phase, three different amounts of organoclay, 2.5, 5 and 7.5 % wt, were dispersed into the epoxy with the mechanical blender followed by the sonication. Both tensile tests and fracture tests were carried on these specimens for characterizing their stiffness, tensile strength and fracture behaviors. The experimental results obtained from tensile tests indicated that with the inclusion of 5% wt organoclay, the stiffness of the epoxy increase up to 16%; however, the corresponding failure strain decreases. Moreover, by utilizing the single-edge-notch bending specimens for fracture tests, the results depicted that the organoclay may dramatically reduce the fracture toughness of the epoxy resin. SEM micrographics demonstrate that the brittle fracture occurs in the nanocomposites. For the examination of organoclay effect on glass/epoxy composites, 5 wt% organoclay were dispersed into the epoxy at the beginning and then the compound were in corporation with dry glass fiber through hand lay-up process to form glass fiber/epoxy/organoclay nanocomposites. Off-axis tensile tests as well as Mode I interlaminar fracture tests were conducted on the fiber nanocomposites to understand the tensile strength and the fracture behavior of the sample with organoclay. From off-axis tests, it is indicated that the nanocomposites exhibit high tensile strength then the conventional fiber composites. On the other hand, the interlaminar fracture toughness decreases in the nanocomposite specimens. The decreasing tendency is similar to that in the pure epoxy case. with glass fiber and epoxy resin. The fracture tests will be performed on the hydraulic MTS machine with 10-1 mm/min loading rate.