| The natural bamboo fiber is abstracted directly from the bamboo material by a unique process,and with the properties of low density, high strength and so on. PLA is polymerized from lactic acid which is fermented by corn stalks or other crops. It is thermoplastic material with low melting point .The natural bamboo fiber & PLA composite material has excellent mechanical properties.It can be degraded into the carbon dioxide and water by microorganism in the soil.At the same time, it does not pollute the environment. This article uses the natural bamboo fiber fabrics and PLA films or PLA filament to make composites and studies the production process and the performance of the composites:1.The research on the structure and performance of the natural bamboo fiber and PLA shows that the natural bamboo fiber contains much substantial hydrophilic groups-hydroxy group.The moisture regain of the natural bamboo fiber is 11.59%, the initial thermal degradation temperature is 319.91℃, the breaking strength is 7.10cN/dtex. The melting point of PLA film is 149℃.2.Study the the hot-pressing process of the composit material. First,we make single-factor and orthogonal testhas with hot-pressing time, temperature and stress. Then by using tensile strength in composite material as a measure of evalation index, we get the best thermal processing conditions: 155℃,25min,15Mpa. On this basis, the longitudinal tensile strength of the composite material reaches the highest value of 76.69MPa when the content of natural bamboo fiber is 46%.3.Study the pretreatment on properties of composite material. By using alkali and KH-550, KH-560, KH-570 or other silane coupling agent to pretreatment the surface of the natural bamboo fibre,the tensile strength of the composite material increases from 76.69MPa to 103.26MPa, 111.03Mpa, 94.69MPa, 92.59MP. At the same time, the bending strength improves some. And the scanning electron microscopy analysis shows that the tensile fracture cross-section of the composites is more smooth after pretreatment.4.Study the wet-heat aging properties and the degradation properties of the composites. After brewing in the boiling water for half an hour, the water absorption of the composites is less than 4%.After immersing in the water at the temperature of 23℃for thirty days, the water absorption achieves to 10.41% maximum, meanwhile the tensile strength reduces a lot. After being buried in the soil for 4 months , the surface morphology damages seriously,and the quality of the sample loses 28.75%～37.31%, the tensile strength loses 79.78%～65.97%.5.Study the influence of the fabric structure on the mechanical properties of composite material.Interweaving the natural bamboo fiber yarn and PLA filament into 11 kinds of fabrics, then hot-pressing the lamination of the fabrics with the PLA film. When bamboo fiber yarn and PLA filament are arrayed by the order of 3:1 in the zonal and the twist of warp of yarn is 90T/10cm,3/1 twill,the study shows that the longitudinal tensile strength is 72.98MPa and the flexural strength of the composite material is 124.58MPa.
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