In blends of elastomers and thermoplastics one component may be regarded as reinforcing the other. Examples are enhancement of tensile strength, tear strength, abrasion resistance, and modulus of elastomers by thermoplastics and improvement of impact resistance and environmental stress-cracking resistance of thermoplastics by elastomers. Certain elastomer-thermoplastic blends are rapidly growing in importance as thermoplastic rubbers because they combine the processing characteristics of plastics with physical properties similar to those of vulcanized elastomers.