Studies on Blends of Polypropylene and its Copolymers with Elastomers

Abstract

Polypropylene is the second most widely used polyolefin after polyethylene as a commodity plastic. It offers a good combination of various physical properties and additionally due to its low cost is an ideal material for various products. However, its main drawback is its low impact strength especially at temperatures below 0 ° C which restrict numerous possible applications including those in packaging, container systems and automotive components. The polyolefin industry including that of polypropylene has focused on research and development of unique and potent catalytic systems such as Zieggler Natta catalysts and metallocene catalysts. The introduction of new comonomers in the polyolefin chain especially in those prepared by metallocene systems has brought about significant improvement in properties of both polyolefins and the elastomers based on them. Elastomers based on both the catalytic systems mentioned above have been used as impact modifiers for polypropylene because of their low glass transitions temperatures. The objective is to obtain a uniform dispersion of domains of elastomer in the polypropylene matrix and thus improve impact strength over a greater temperature range. The following work focuses on the mechanical properties of blends of homopolymer of polypropylene and a high impact copolymer of polypropylene with three classes of elastomers: • Ethylene propylene rubber elastomers • Multi Zone Circulating Reactor Catalysis based elastomers • Alpha-olefin copolymers Mechanical properties such as Izod impact strength, stiffness, tensile strength and Gardner impact strength measured at low temperatures will be measured. Thermal characterization by differential scanning calorimetry was carried out to substantiate the results