| Summary: | 碩士 === 逢甲大學 === 纖維與複合材料學系 === 102 === An optimized synthesis of nanometer silica particles by sol-gel method take advantage of Tetraethoxysilane (TEOS). Preparation of nano-silica / epoxy mixed solution thorugh ultrasonication and mechanical agitation. Using differential scanning calorimetry (DSC) to explore the effect of different nano-silica added proportions on glass transition temperature (Tg) of resin system.
Glass fabric/nano-silica/epoxy composite laminates made by hand lay-up and hot pressing method. The purpose of this study is to evaluate the reinforced role of nano-silica on the mechanical properties and the interlaminar fracture behaviour of fibre reinforced toughened epoxy. Flexural test, short-beam test and fracture toughness test (Double Cantilever Beam test) were performed to evaluate mechanical performance.
Based on the experimental results showed that glass transition temperature (Tg) of resin system does not significantly influenced by adding with different amounts of nano-silica. Flexural strength and flexural modulus increased with increasing of nano-silica added amounts. The flexural strength and flexural modulus of the composites enhance 9.98% and 13.74%, respectively, with silica particles added 8 wt.% loading. Compared to the neat epoxy, the interlaminar shear strength of silica composites increased of 16.31% for 12 wt.% silica loading. The mode I fracture toughness of laminates also exhibt increased with increasing of nano-silica weight fraction. The GIC value enhance 55.7% with adding 12 wt.% nano-silica weight fraction. According to observ the photos of SEM after DCB tested specimen showed that including crack pinning, crack deflection, particle pull-up and microcracks etc. failure modes on the fracture surface. It demonstrates the composite materials could absorb more energy and causes the GIC increased when added nano-silica into epoxy system.
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