| Due to high specific surface areas, length to diameter ration, small spaces among fibers, ultrafine fibers show great potential application in fields such as filter media, tissue engineering scaffolding, protective clothing and composite material. Electrospinning is a simple and versatile technique of generating continuous ultrafine fibers. This thesis research work includes the following aspects:(1) The preparation of cellulose acetate (CA) ultrafine fibers, polyurethane (PU) and CA/PU composite ultrafine fibers from electrospinning was studied. All fibers were embedded into epoxy resin to fabricate fiber reinforced composite films. Their morphology, light transmittance and mechanical properties were investigated in terms of fiber content in the composite films.(2) The method of fabricating uniaxially aligned electrospun fibers was studied. Electrospun fibers could be oriented circumferentially by rotating a cylindrical collector at a very high speed up to thousands of rpm; Uniaxially aligned electrospun ultrafine fibers reinforced composite materials with high visible light transmittance were obtained successfully.(3)Ultrafine cellulose acetate fibers with an average diameter of 400 nm were synthesized by electrospinning. The cellulose acetate fibers were embedded into epoxy resin to fabricate reinforced composite films. Their morphology, light transmittance and mechanical properties were characterized by scanning electron microscopy (SEM), light transmittance test, and tensile test. Due to the ultrafine diameter of cellulose acetate fiber, the composite film showed improved fiber/resin interfacial adhesion. This led to high visible light transmittance even though the composite film had a fiber volume as high as 31 wt%. The composite film exhibited enhanced mechanical properties as compared to the pure epoxy resin. |
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