Preparation and Properties of Environmentally Friendly Self-reinforced Composites

采用环境友好型材料制备了增强体与基体均为化学成分相同的自增强复合材料。本课题研究了两种复合材料，即全纤维素复合材料和全聚乙烯醇（PVA）复合材料的结构与性能。前者全部由生物质资源构成。我们尝试了两种不同的方法。一种是通过使用溶剂选择性地溶解纤维素纤维表面，另一种是通过使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。采用这些方法可以成功地将纤维表面转化为基体，制备出全纤维素复合材料。复合材料的力学性能上级优于传统的玻璃纤维增强复合材料（GFRP），同时还具有高的耐热性和光学性能。 ...更多信息 y.本论文的部分工作获得了2007年日本纤维素学会的奖项。PVA是一种可生物降解的聚合物，也被称为水溶性聚合物。然而，需要高温（沸水）来溶解高度结晶的PVA。因此，可以通过结晶度的不同来区分PVA的水溶性。通过将PVA水溶液浸渍到高拉伸/高结晶度PVA纤维中，可以制备全PVA复合材料。通过优化制备方法和条件，可制备出模量> 17 GPa、拉伸强度> 600 MPa的全PVA复合材料。这与高性能复合材料的那些相对应，这表明全PVA复合材料可以作为常规GFRP的替代物。该复合材料具有光学透明性，这些性能也可以通过复合材料中纤维的排列来控制。在这三年中，环境友好型自增强复合材料的制备和性能的项目按计划进行。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