Preparation and Properties of Environmentally Friendly Self-reinforced Composites

采用环保材料制备自增强复合材料，增强材料与基体由化学性质相同的物质组成。本课题研究了全纤维素复合材料和全聚乙烯醇（PVA）复合材料的结构和性能。前者完全由生物质资源组成。我们尝试了两种不同的流程。一种是用溶剂选择性溶解纤维素纤维表面，另一种是用超临界二氧化碳作为反应介质将纤维素纤维表面转化为热塑性纤维素衍生物。利用这些方法将纤维表面转化为基体，可以成功制备全纤维素复合材料。复合材料的力学性能优于传统的玻璃纤维增强复合材料（GFRP）。他们还发现它们具有高热阻和高光学透明度。这项工作的一部分被授予2007年日本纤维素学会奖。PVA是一种可生物降解聚合物，又称水溶性聚合物。然而，需要高温（沸水）来溶解高结晶的PVA。因此PVA的水溶性可以通过结晶度的不同来区分。将聚乙烯醇水溶液浸渍在高拉伸/高结晶聚乙烯醇纤维中，可制备全聚乙烯醇复合材料。通过优化制备方法和条件，可制得模量> 17 GPa、抗拉强度> 600 MPa的全pva复合材料。这些与高性能复合材料相对应，这表明全pva复合材料可以作为传统GFRP的替代品。复合材料是光学透明的，这些性能也可以通过复合材料中的纤维排列来控制。在这三年中，环保型自增强复合材料的制备和性能项目按照计划进行。少

Self-reinforced composite, in which reinforcement and matrix are both composed of chemically same substance, was prepared using environmentally-friendly materials. The structure and properties of two kinds of composites, that is, all-cellulose composite and all-poly (vinyl alcohol) (PVA) composite, were investigated in this research project. The former is composed of totally biomass resource. We tried two different processes. One is by dissolving the cellulose fiber surface selectively using solvent, and the other is by converting the cellulose fiber surface into thermoplastic cellulose derivative using supercritical carbon dioxide as reaction medium. The all-cellulose composite could be successfully prepared by converting the fiber surface into the matrix using these methods. The composites showed excellent mechanical properties superior to those of conventional glass-fiber reinforced composite (GFRP).They were also found to possess high thermal resistance and high optical transparenc … More y. Part of this work was awarded the 2007 prize of the cellulose society, Japan.PVA is a kind of biodegradable polymers, and also known as a water soluble polymer. However, high temperature (boiling water) is needed to dissolve highly crystalline PVA. So water-solubility of PVA can be distinguished by the difference of the crystallinity. All-PVA composite could be prepared by impregnating PVA aqueous solution into highly drawn / high crystalline PVA fibers. By optimizing preparation methods and conditions, the all-PVA composite with its modulus > 17 GPa, tensile strength > 600 MPa could be prepared. These correspond to those of high performance composites, which indicates that all-PVA composite can be a good candidate as an alternative of conventional GFRP. The composite was optical transparent, and these properties could be also controlled by the fiber alignment in the composite.During these three years, the project of the preparation and properties of environmentally friendly self-reinforced composites proceeded with the program as arranged. Less