Preparation And Properties Of Bamboo Fiber And Its Unidirectional Continuous Reinforced Composites

In this paper, according to the performance differences at different places from a piece of bamboo, two kinds of bamboo fibers were extracted from the outer and inner of bamboo strips by the combination of mechanical and chemical method. The performences of the two kinds of bamboo fibers were analyzed and compared, and the fibers with better mechanical properties extracted form the outer of bamboo strips were used to fabricate the unidirectional continuous bamboo fibers reinforced unsaturated polyester resin composite. After determining the cuing system of the composite, the influences of the weight fraction and the stitch parameters of bamboo fibers on the longitudinal mechanical properties and water absorption properties of composites were studied. Then the silane treatment of bamboo fibers on the longitudinal performents of composites were discussed, the reinforcing mechanisms were investigated, and the mechanical properties of the composites were evaluated.The two kinds of bamboo fibers extracted form different regions of bamboo have great differences in performences. The fibers extracted from the outer of bamboo strips are coarser and have better mechanical properties, whose tensile strengh, tensile modulus, elongation at break, work of fracture is 44.76%,124.60%, 20.68%,123.35% higher than the fibers extracted from the inner of bamboo strips. They have similar chemical compositions, and the crystallinity of the fibers extracted from the outer of bamboo strips is 34.78% higher than that of the fibers extracted from the inner of bamboo strips.The bamboo fiber content has a significant influence on the performences of unidirectional continuous bamboo fibers reinforced unsaturated polyester resin composites. With the increase of bamboo fiber content, the mechanical properties of the BF/UP composite increased with bamboo fibers content up to 50% and then decreased. When the bamboo fiber content is 50%, the tensile and flexural properties of the composite attain a peak. To the dynamic mechanical properties of the composites, with the increase of fiber content, the storage modulus of the composite gets a similar variation tendency with the tensile and flexural properties, the Tg of the composite decreases slightly, and the wideth of the tan δ peak becomes broader. When the bamboo fiber content is 50%, the storage modulus of the composite yielded the highest value and the tan δ of the composite yielded the lowest value. In addition, the water absorption property of the composite increases with the increase of the bamboo fiber content. The stitch line spacing of the bamboo fibers has signicant influence on the tensile strength, tensile modulus, flexural modulus and shear strength of the composites, while it is not applicable in flexural strength of the compisites. When the stitch line spacing is 3cm, the composite attains the best mechanical properties. However, the sewing yarn materials have little effect on the mechanical properties of the composite.The performences and the interfacial bonding of the composites are improved greatly by Silane treatment. Silane treatment can greatly improve the performences and the interfacial bonding of the composites. The composite has the best comprehensive properties with the silane coupling agent concentration of 3%, whose tensile strength, flexural strength, flexural modulus and shear strength increase by 34.29%,15.95%,11.26% and 29.39% repectively. Compared the untreated composite, the storage modulus of the composite increases by 63.80%, the loss factor of the composite decreases, and the 24h and 720h water absorption of the composite decrease by 55.35% and 27.32%. The evaluation of mechanical properties of the composite shows that, the unidirectional continuous bamboo fibers/UP composite has excellent mechanical properties, can meet the requirements of the mechanical properties of wind power blade material, highway crach barrier, ship materials, window frames and so on. The unidirectional continuous bamboo fibers/UP composite has the potential to replace the application of glass fibers reinforced plastic composite in these areas.