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Studies on Development of Molecular Composites Directed to Substitution of High-Performance FRP

替代高性能FRP的分子复合材料开发研究

基本信息

批准号：
02555182
负责人：
TAKAYANAGI Motowo
金额：
$ 6.78万
依托单位：
Kyushu Sangyo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1992
项目状态：
已结题

项目摘要

FRP has disadvantages of limitation in fiber strength and heterogeneous texture. Molecular composite(MC) composed of rigid rodlike molecule and fexible coil-like molecule is expected to be single-phase and free from defects. This research project mainly placing target to the system of poly(p-phenyleneterephthalamide)(PPTA) and nylon 6(Ny6) revealed the following conclusions: (1) a stable single-phase MC is obtained by using a matrix polymer with huge molecular weight, with which diffusion and phase separation of rigid rodlike molecules in MC are hindered, (2)clustering of rod molecules reduces the efficiency of stress transfer and the modulus and yield stress of MC are decreased, (3) the increased molecular weight of rod molecules increases modulus and yield stress of MC, which can be similarly explained as the theory of FRP predicts, and (4) the elongation of MC is small if only the intermolecular force between rod and flexible molecules is employed for stress transfer. By block copolymerization of rod and flexible chain blocks, the elongation of MC is highly improved due to the effect of stress transfer from rod to flexible molecules. Such a chemical modification of rod molecules is impossible in case of reinforcing fiber in FRP.A MC prepared by using Ny6 with molecular weight of 260,000 showed entirely dark image under polarization microscope with crossed polars after hot-pressed at temperature above the melting temperature of Ny6 indicating a single phase, stable MC. FTIR of N-H stretching band showed a sharp, single absorption, indicating cross-hydrogen bonding between amide groups of PPTA and Ny6. No crystallization and melting peaks in DSC curves were found in this case. Molecular dispersity of MC was supported with these observations.

玻璃钢具有纤维强度受限、织构不均匀等缺点。由刚性棒状分子和柔性线圈状分子组成的分子复合材料有望成为单相、无缺陷的材料。本课题主要以聚对苯对苯二甲酰胺（PPTA）与尼龙6（Ny6）体系为研究对象，得出以下结论：(1)采用大分子量的基体聚合物获得稳定的单相MC，阻碍了刚性棒状分子在MC中的扩散和相分离；(2)棒状分子的聚集降低了应力传递效率，降低了MC的模量和屈服应力；(3)棒状分子分子量的增加增加了MC的模量和屈服应力，这与FRP理论的预测类似。(4)仅利用棒与柔性分子之间的分子间力进行应力传递时，MC的伸长率较小。通过棒材与柔性链块的嵌段共聚，由于棒材与柔性分子之间的应力传递作用，大大提高了MC的伸长率。这种棒分子的化学修饰在FRP中是不可能的。用分子量为26万的Ny6制备的MC在高于Ny6熔点的温度下热压后，在极化显微镜下呈现出完全黑暗的交叉极性图像，表明MC为单相稳定的MC。N-H拉伸带的FTIR显示出明显的单吸收，表明PPTA与Ny6酰胺基团之间存在交叉氢键。在DSC曲线上没有发现结晶和熔化峰。这些观察结果支持了MC的分子分散性。