Some considerations concerning the dynamic mechanical properties of cured styrene–butadiene rubber/polybutadiene blends

The dynamic mechanical response of several binary mixtures of a styrene–butadiene copolymer and high cis‐polybutadiene has been studied. The loss tangent and shear modulus were measured with a free damping torsion pendulum at temperatures between 143 and 343 K in argon atmosphere. From the loss tangent data the glass transition temperature of each sample was evaluated. The results can be represented by the Fox equation that relates the glass transition temperature of the blend with that of constituent polymers. The influence in the loss tangent data of the crystallization of the high cis BR used in the blend is discussed. A study of the separation of the crystalline and amorphous parts in the polybutadiene using the storage modulus data is presented. Finally, the loss of crystallinity at different contents of SBR in the blend is analysed using the dynamic mechanical data. © 2000 Society of Chemical Industry