ABSTRACT
Polypropylene (PP) is characterized by high tensile strength, high stiffness, and high heat deflection temperature under load. However, one major deficiency of PP is its low impact resistance, particularly at low temperatures. Blending PP with an elastomeric modifier provides a simple way to significantly improve impact strength of the base resin. At present, ethylene-propylene rubber (EPR) and ethylene-propylene diene rubber (EPDM) are the most common types of elastomer used to modify the impact properties of PP resins [1]. Other elastomeric modifiers include natural rubber [2], styrene-butadienestyrene block copolymer (SBS) and its hydrogenated analogue SEBS [3], polyisobutylene (PIB) [4], and very low density polyethylene (VLDPE).
