School of Engineering and Materials Science, Centre for Materials Research, Queen Mary University of London, Mile End Road, E1 4NS London, United Kingdom.
ACS Appl Mater Interfaces. 2010 Mar;2(3):919-26. doi: 10.1021/am900859c.
The area of self-reinforced polymer composites is one of the fastest growing areas in engineering polymers, but until now these materials have been mainly developed on the basis of thermoplastic fibers of moderate performance. In this work, we report on a new type of self-reinforced composites based on high-performance aramid fibers to produce an "all-aramid" composite by applying a surface-dissolution method to fuse poly(p-phenylene terephthalamide) (PPTA) fibers together. After immersion in concentrated (95%) sulphuric acid (H(2)SO(4)) for a selected period of time, partially dissolved fiber surfaces were converted into a PPTA interphase or matrix phase. Following extraction of H(2)SO(4) and drying, a consolidated all-aramid composite was formed. The structure, mechanical- and thermal properties of these single-polymer composites were investigated. Optimum processing conditions resulted in unidirectional composites of high reinforcement content (approximately 75 vol %) and good interfacial bonding. The all-aramid composites featured a Young's modulus of approximately 65 GPa at room temperature, and a tensile strength of 1.4 GPa, which are comparable with or exceed the corresponding values of conventional aramid/epoxy composites. However, since fiber, matrix and interphase in all-aramid composites are based on the same high-temperature resistant PPTA polymer, a high modulus of approximately 50 GPa was maintained up to 250 degrees C, demonstrating the potential of these materials for high-temperature applications.
自增强聚合物复合材料是工程聚合物中增长最快的领域之一，但到目前为止，这些材料主要是基于中等性能的热塑性纤维开发的。在这项工作中，我们报告了一种新型的自增强复合材料，该复合材料基于高性能芳纶纤维，通过采用表面溶解法将聚对苯二甲酰对苯二胺（PPTA）纤维融合在一起，制备出一种“全芳纶”复合材料。将纤维在浓（95%）硫酸（H₂SO₄）中浸泡一段时间后，部分溶解的纤维表面转化为 PPTA 相间或基体相。在提取 H₂SO₄和干燥后，形成了一个固结的全芳纶复合材料。研究了这些单聚合物复合材料的结构、力学和热性能。最佳的加工条件得到了高增强含量（约 75%体积）的单向复合材料和良好的界面结合。全芳纶复合材料在室温下的杨氏模量约为 65 GPa，拉伸强度为 1.4 GPa，与传统芳纶/环氧复合材料的相应值相当或超过。然而，由于全芳纶复合材料中的纤维、基体和相间都是基于相同的耐高温 PPTA 聚合物，因此在 250°C 时仍保持约 50 GPa 的高模量，这表明这些材料在高温应用中的潜力。
