Mechanical properties, oil resistance, and thermal aging properties in chlorinated polyethylene/natural rubber blends

The use of natural rubber (NR) for partly substituting elastomeric chlorinated polyethylene (CPE) was determined. Mechanical and thermal aging properties as well as oil resistance of the blends were also investigated. The amount of NR in blends significantly affected the properties of the blends. The blends with NR content up to 50 wt % possessed similar tensile strength to that of pure CPE even after oil immersion or thermal aging. Modulus and hardness of the blends appeared to decrease progressively with increasing NR content. These properties also decreased in blends after thermal aging. After oil immersion, hardness decreased significantly for the blends with high NR content, whereas no change in modulus was observed. The dynamic mechanical properties were determined by dynamic mechanical thermal analysis. NR and CPE showed damping peaks at about -40 and 4 degreesc, respectively; these values correlate with the glass-transition temperatures (T-g) of NR and CPE, respectively. The shift in the T-g values was observed after blending, suggesting an interfacial interaction between the two phases probably caused by the co-vulcanization in CPE/NR blends. (C) 2002 John Wiley Sons, Inc.