Functional Self-Reinforced Composites using Stereocomplex Fiber

本研究的目的是创建/表征自增强复合材料，具有优异的机械性能，用于各种应用。例如，聚（甲基丙烯酸甲酯）的自增强复合材料，其中增强纤维和基质都是聚（甲基丙烯酸甲酯），不应遭受差的纤维-基质界面强度，因此具有比用其它纤维增强的复合材料显著更大的拉伸/弯曲/断裂/疲劳性能。尽管聚（甲基丙烯酸甲酯）由于其优异的生物相容性可用于多种医疗/牙科应用，但将常规聚（甲基丙烯酸甲酯）纤维掺入聚（甲基丙烯酸甲酯）基质而不损失纤维的链取向实际上是不可能的，因为它们具有相同的热性能。 因此，我们的方法是基于形成立体复合纤维的新想法，例如，从全同立构和间同立构聚（甲基丙烯酸甲酯）的混合物，其具有比自增强复合材料的加工温度显著更高的熔融温度。从坦克装甲到宇宙飞船的各种应用都需要高强度聚合物材料，而不仅仅是医疗/牙科领域。用立体复合纤维代替传统复合材料中使用的玻璃纤维或碳纤维，可以实现两个重要的改进：一是界面强度将大大提高;二是可以制备一系列新的功能复合材料，这取决于立体复合纤维和基体材料的选择，如导电聚合物、光响应聚合物和其他智能材料。这些材料将在设想的“火星使命”奋进中作为结构元件、电子元件和光学传感器发挥重要作用。

The objective of this research is to create/characterize Self-Reinforced Composites that possess excellent mechanical properties for a variety of applications. Self-reinforced composites of poly(methyl methacrylate), for example, where the reinforcing fiber and the matrix are both poly(methyl methacrylate), should not suffer from poor fiber-matrix interfacial strength and hence have significantly greater tensile/flexural/fracture/fatigue properties than the composites reinforced with other fibers. Even though poly(methyl methacrylate) may be used in several medical/dental applications due to its excellent biocompatibility, incorporation of the regular poly(methyl methacrylate) fibers into poly(methyl methacrylate) matrix, without losing chain orientation of the fibers, is virtually impossible because they have the same thermal property. Hence, our approach is based on the novel idea of forming stereocomplex fibers, for example, from mixtures of isotactic and syndiotactic poly(methyl methacrylate), which have significantly higher melting temperatures than the processing temperature of the self-reinforced composite. High strength polymeric materials are needed for a variety of applications ranging from tank armor to spaceships, not just medical/dental fields. By replacing the fibers like glass or carbon conventionally used in composite materials with stereocomplex fiber, we can achieve two important improvements: one, the interfacial strength will be greatly enhanced, and two, a whole host of new functional composites can be made, depending on the selection of the materials to make stereocomplex fiber and the matrix, such as conducting polymers, photo-responsive polymers, and other smart materials. These materials will play an important role as structural elements, electronic components, and optical sensors in the envisioned "mission to mars" endeavor.