A Mechanically Strong, Aging-Resistant, and Reprocessable Elastomer Based on Carboxylated Nitrile Butadiene Rubber (XNBR) Composite for Photothermal Conversion Application

Designing elastomers with integrated excellent mechanical strength and elasticity, aging resistance, reprocessability, and photothermal conversion capabilities remains a critical challenge in sustainable materials science. Here, we report a simple and environmentally friendly strategy to fabricate multifunctional elastomers by incorporating grape seed proanthocyanidin (GSP)─a natural biofiller─into carboxylated nitrile butadiene rubber (XNBR) matrix via a solvent-free mechanical blending process. The compatibility between GSP and XNBR is improved by incorporating ZnO, which forms metal coordination bonds between XNBR and GSP. The XNBR composite exhibits excellent mechanical properties, especially the composite with 30 per hundred rubber (phr) GSP, with robust tensile strength (10.3 MPa) and elongation at break (1004%). This is attributed to the hydrogen and metal coordination bonds between GSP and XNBR. Remarkably, the composite with 30 phr GSP exhibits superior aging resistance (tensile strength retention rate = 88%) in thermo-oxidative aging (80 °C, 24 h) and reprocessability. Critically, the composite exhibits stable photothermal conversion under near-infrared (NIR) irradiation, reaching temperatures up to 296 °C, and successfully powers a thermoelectric generator to drive kinetic devices, showing excellent application potential for efficient solar energy utilization.