Polyolefin blends

Polyolefin blends of proper morphology exhibit physical properties from high‐extension, low‐modulus elastomers to high‐modulus tough resins. The morphology is controlled by rheology of the polymers, blending conditions and the use of graft polymer compatibilizers. The graft polymers were synthesized by polymerizing isotactic polypropylene with unsaturation in an ethylene‐propylene‐diene terpolymer. Graft copolymers result in smaller phase sizes and a more stable morphology for the blends. The development of polyolefin blends is reviewed with emphasis on materials with high concentration of elastomer phase.