Curing characteristics and mechanical properties of natural rubber/chloroprene rubber and epoxidized natural rubber/chloroprene rubber blends

Curing characteristics and Mechanical properties of natural rubber (NR)/chloroprene rubber (CR) and epoxidized natural rubber (ENR)/CR blends were studied. ENR 50, SMR L and CR were used as the elastomers. The composition of SMR L and ENR 50 was varied from 0 to 100% rubber. Results show that the Mooney scorch time, t5 and cure index, ΔtL deviate negatively from the calculated value based on the interpolation between the properties of the two component elastomers. The negative deviation was attributed to the induction effect of ENR 50 and SMR L on CR molecules that causes an overall increase in the rate of crosslinking of the blend. However, for tensile modulus, hardness and tensile strength, a positive deviation was observed. The maximum value of tensile modulus and hardness was obtained at 25/75 (wt/wt) of ENR 50/CR and SMR L/CR blends whereas for tensile strength at 75/25 (wt/wt) of ENR 50/CR and SMR L/CR blends.