Aramid Nanofiber-Reinforced Natural Rubber Composites: Preparation, Properties, and Multifunctional Applications

Abstract

To address the inherent performance bottlenecks of natural rubber (NR) such as insufficient mechanical strength, poor flame resistance, and limited environmental stability, aramid nanofibers (ANFs) were used as reinforcing fillers and silver nanowires (AgNWs) as functional fillers to prepare ANFs/NR and AN/AgNW composite materials via a solution-casting method. This work investigated the effects of ANF loading on the microstructure, mechanical properties, flame retardancy, environmental stability, and thermal conductivity of ANFs/NR composites, and the regulatory mechanism of AgNWs on the thermal and sensing performance of the composites was also explored. The ANFs could effectively improve the mechanical properties of NR: the tensile strength of the ANFs/NR1 composite films increased 133% compared with pure NR, reaching 9.81 MPa. The ANFs/NR composites maintained an intact structure after 12 h immersion in strong acid (pH = 1) and strong alkali (pH = 14) solutions and retained toughness without brittle fracture after liquid nitrogen (−196 °C) treatment. Although ANFs can reduce the flammability of NR, the modified composites still fail to meet the criteria for flame-retardant materials. AgNWs constructed a continuous conductive network on the surface of ANFs/NR composites; the AN/AgNWs1.5 composite film could rapidly heat up to 72.1 °C under 1 V and to 147.7 °C under 3 V. This study provides a feasible strategy for fabricating natural rubber-based composite films that integrate high strength, extreme environment resistance, electrothermal performance, and sensing capabilities.