Studies on the effect of reactive polypropylene on the properties of filled polyolefin composites. Part 2. Optimization of product composition and mechanical properties of modified polypropylene composites.

The mechanical properties of polypropylene composites based on inorganic fillers can be significantly improved if a small part of the added polypropylene is chemically modified by maleic anhydride. The effect of addition of maleic anhydride modified polypropylene in calcium carbonate- as well as in zeolite-filled polypropylene composites is to increase tensile strength and impact resistance. The ultimate properties of the composites, however, are determined by both filler and modifier concentrations. This paper reports the design and execution of a planned experiment using a statistical method to study the complex dependence of product composition on the ultimate composite properties. While the effect of modifier concentration on tensile strength of all composites studied is unique and positive, the impact strength of zeolite-filled polypropylene composite shows a more complex dependence on the modifier and filler concentrations. Thus, appropriate selection of a surface diagram involving composition and properties helps in the design of polypropylene composites with a wide range of properties.