Microwave irradiated polyester staple fibers for natural rubber with excellent interface performance

The excellent bonding performance between polyester fibers and rubber is key to the high elasticity and fatigue resistance of rubber composite materials. Here, the modified polyester staple fiber (MPET) was obtained by microwave irradiation and surface modification with γ-aminopropyltriethoxysilane (KH550). The results revealed that KH550 reacted with the carboxyl groups on the surface of PET and thus adhered to the fiber surface, which was beneficial in improving compatibility with rubber. When reinforcing natural rubber (NR), MPET combined with the NR molecular chain flexibility due to the rigidity of its own main chain structure. This synergy resulted in the formation of inter-chain entanglements, contributing to a reduction in internal energy dissipation and heat generation within the composite. As the MPET dosage is augmented, the maximum torque of the NR compound during the mixing process exhibits an upward trend. In parallel, the cured NR rubber experiences a gradual reduction in both tensile strength and elongation at break, accompanied by a progressive increase in hardness. Furthermore, a notable elevation in tear strength is observed. This observed trajectory accentuates the intricate interplay between the dosage of MPET and the mechanical attributes of the NR rubber composite. The results of Rubber Processing Analyzer (RPA), Dynamic Mechanical Analysis (DMA) and Scanning Electron Microscope (SEM) indicate that the interfacial bonding between MPET and NR shows promising prospects as rigid short fibers for reinforcing non-polar rubber.