Jackfruit Latex as a Biomass Reinforcing Agent for Mechanically Robust Natural Rubber Composites

ABSTRACT Strength and toughness are crucial properties for rubber composites. However, materials with dense crosslinking networks exhibit high strength but are brittle, whereas those with sparse networks are flexible but weak, making the simultaneous enhancement of both properties a long‐standing challenge. In this work, biomass jackfruit latex (JL) was introduced as a green reinforcing agent to enhance the mechanical robustness of natural rubber (NR). The oxygen‐containing groups in JL decompose at vulcanization temperature to generate reactive radicals, which participate in the sulfur vulcanization process and promote the formation of additional crosslinking points, thereby significantly improving the mechanical strength of NR. JL also forms a hydrogen‐bonded network through its hydroxyl groups, which acts as a sacrificial network that preferentially ruptures upon deformation to dissipate energy, thereby enhancing the toughness of NR. As a result, JL/NR composites exhibited a 60.2% increase in tensile strength (from 15.09 to 24.17 MPa) and a 102.0% increase in G c (from 15.1 to 30.5 kJ/m 2 ), respectively. This study not only provides a sustainable and effective strategy for designing NR composites with simultaneously enhanced strength and toughness, but also offers guidance for the development of eco‐friendly biomass elastomers with excellent mechanical robustness.