Bamboo-like ultra-high molecular weight polyethylene fibers and their epoxy composites

It is important for most structural material to achieve both good strength and toughness. However, they are generally mutually exclusive, which is the lower-strength, and hence higher-toughness. Ultra-high molecular weight polyethylene (UHMWPE) fibers have excellent mechanical properties, unfortunately, the interfacial adhesion of UHMWPE fiber reinforced polymer composites is extremely low. Inspired by the shape of bamboo in nature, we herein designed and prepared UHMWPE fiber with new structure. UHMWPE fibers were periodically decorated with polymer lamellar crystals using a polymer solution crystallization method, resulting in bamboo-like structure. It was showed that the strength and toughness of bamboo-like UHMWPE fibers reinforced epoxy (EP) composites were improved simultaneously, which were attributed to the special interface structure between UHMWPE fibers and EP. The strengthening mechanism of the composites is mainly due to the bamboo-like crystals on the fiber surface, which plays a role of pinning and increases the crack propagation path.