Abstract

Rubber materials are extensively utilized in industrial applications because of their elasticity and ability to recover after deformation. However, vulcanized rubbers are prone to permanent deformation under thermal or mechanical stress due to variations in crosslink density. This study evaluated the recovery behavior of rubber-based composites blended with thermoplastic resins under circular deformation conditions. Six composite formulations were prepared by varying the plasticizer and vulcanization accelerator contents. The composites were processed via melt mixing and hot pressing, and rheometer measurements were performed to determine their crosslinking characteristics. Circular deformation tests were conducted at room temperature and at 80°C to quantify their recovery performance after thermal aging. The 100% rubber vulcanizate exhibited the highest initial recovery (92.5%) and achieved full shape restoration within 8 h at room temperature. In contrast, thermoplastic-blended samples showed lower initial recoveries (78.7~86.2%) and delayed full recoveries up to 45h. At 80°C, all samples experienced residual strain, with the rubber-only sample recovering up to 93.7%, whereas blended samples ranged between 71.2% and 78.0% recovery. Notably, despite the reduced recovery performance, the thermoplastic blends exhibited enhanced mechanical strength and abrasion resistance. These results highlight the trade-off between thermal recovery and mechanical reinforcement when thermoplastics are incorporated. The insights gained from this study can be used to optimize the fabrication of thermoplastic-rubber composites for applications requiring tailored elastic and thermal-aging performance.

Keywords: polyvinyl chloride;crosslink density;shape recovery behavior;circular deformation;thermal aging resistance