Characterization of composites based on chlorosulfonated polyethylene rubber/chlorinated natural rubber/waste rubber powder rubber blends

Chlorosulfonated polyethylene rubber (CSM) was blended with chlorinated natural rubber (CNR) with various formulations and blend ratios (CSM/CNR: 100/0; 75/25; 50/50; 25/75; 0/100) keeping the total waste rubber powder (WRP) content constant at 50 phr (parts per 100 rubber). Rheological, mechanical, dynamic mechanical and thermal aging properties as well as irradiation resistance were used as characterization of the blends. The amount of CNR in blends significantly affected the properties of the blends. The CSM/CNR/WRP rubber blend (50/50/50) possessed higher tensile strength compared with pure CSM and CNR rubber even after irradiation or thermal aging. Modulus, tensile strength and hardness of the blends appeared to increase, but elongation at break decreased progressively with increasing CNR content. These properties decreased in rubber blends after thermal aging. After irradiation, hardness, modulus and tensile strength increased up to 200 kGy and then decreased significantly for the blends with high CNR content, whereas no change in modulus was observed. CNR and CSM showed damping peaks at about 65 and −45°C, respectively, and these values correlate with the glass transition temperatures ( T g s) of CNR and CSM, respectively. The shift in the T g values was observed after blending, suggesting an interfacial interaction between the two phases probably caused by the covulcanization in CSM/CNR blends.