Enhancing Tear Resistance of Natural Rubber‐Based Composites Through Filling Surface Treated Short Nylon Cords

ABSTRACT Short‐fiber reinforcement effectively enhances rubber composites, particularly in terms of tear resistance, which is critical for applications such as tracks and tires. However, the poor fiber‐rubber interfacial compatibility remains a major challenge. In this study, a blend of natural rubber, styrene butadiene rubber, and butadiene rubber was used as the base matrix. Short nylon cords (SNCs) with two different surface treatments, untreated and resorcinol‐formaldehyde‐latex (RFL) dipped, were mixed into the rubber matrix at lengths of 0.5 and 1.0 cm and contents of 1–5 phr. The effects of fiber treatment, length, and content on the performance of composites were investigated. The results show that RFL treatment significantly enhances fiber‐rubber interfacial adhesion. Notably, the incorporation of RFL‐treated SNCs with a length of 1.0 cm at a loading of 2 phr increased the tear strength from 33.63 to 42.41 kN/m (approximately 26.1%) and the stress at 300% elongation from 10.56 to 12.43 MPa (approximately 17.7%), compared with the unfilled rubber matrix. Although the introduction of SNCs slightly increased abrasion loss, RFL‐treated fibers effectively mitigated this drawback. These findings demonstrate that an appropriate combination of fiber surface treatment, length, and loading is critical for balancing reinforcement and durability in short‐fiber‐reinforced rubber composites, providing practical guidance for the design of high‐performance rubber materials.