Zhang Zhuolei, Zhao Yao, Li Haoqi, Percec Simona, Yin Jie, Ren Fei
Department of Mechanical Engineering, Temple University, Philadelphia, PA, 19122, USA.
Temple Materials Institute, Temple University, Philadelphia, PA, 19122, USA.
Sci Rep. 2019 May 9;9(1):7183. doi: 10.1038/s41598-019-43629-1.
High-performance fibers made of poly-(p-phenylene terephthalamide) (PPTA) with high stiffness and high strength are widely used in body armor for protection due to their high degree of molecular chain alignment along the fiber direction. However, their poor mechanical properties in the transverse direction and low surface friction are undesirable for applications requiring resistance to ballistic impact. Here we provide a simple yet effective surface engineering strategy to improve both the transverse mechanical properties and the tribological property by coating PPTA fibers with ultra-high molecular weight polyethylene (UHMWPE) embedded with silica nanoparticles. The coated-PPTA fiber shows remarkable enhancement in transverse mechanical properties including ~127% increase of Young's modulus, which is attributed to both the alignment of UHMWPE chains in the transverse direction and the embeded ceramic nanoparticles. Meanwhile, the surface friction of the coated fiber increases twofold as a result of the ceramic nanoparticles. In addition, the coated fibers exhibit an enhanced chemical resistance to external harsh environment. The improved transverse mechanical properties, surface frictional characteristics, and chemical resistance demonstrate that coating with UHMWPE and ceramic nanoparticles can be used as an effective approach to enhance the performance of PPTA and other high-performance polymer fibers for body armor applications.
由聚对苯二甲酰对苯二胺（PPTA）制成的具有高刚度和高强度的高性能纤维，因其分子链沿纤维方向的高度排列而广泛用于防弹衣防护。然而，它们在横向方向上较差的机械性能和低表面摩擦力对于需要抵抗弹道冲击的应用来说是不理想的。在此，我们提供了一种简单而有效的表面工程策略，通过用嵌入二氧化硅纳米颗粒的超高分子量聚乙烯（UHMWPE）涂覆PPTA纤维来改善横向机械性能和摩擦学性能。涂覆后的PPTA纤维在横向机械性能方面表现出显著增强，包括杨氏模量提高约127%，这归因于UHMWPE链在横向方向上的排列以及嵌入的陶瓷纳米颗粒。同时，由于陶瓷纳米颗粒，涂覆纤维的表面摩擦力增加了两倍。此外，涂覆纤维对外部恶劣环境表现出增强的耐化学性。改进后的横向机械性能、表面摩擦特性和耐化学性表明，用UHMWPE和陶瓷纳米颗粒进行涂覆可作为提高PPTA和其他高性能聚合物纤维用于防弹衣应用性能的有效方法。
