DEVELOPMENT OF FILLED POLYOLEFIN COMPOSITIONS FOR INJECTION MOLDED PRODUCTS

Abstract

To develop filled polymer compositions based on polypropylene with different contents of calcite concentrate as a filler and the newest polyolefin elastomer as a modifier; to define the influence of the compositions on their rheological and physico-mechanical properties for production injection molded goods. The values of viscosity, melt flow index, tensile strength, elongation, and impact strength and frost resistance of the compositions depending on their composition are determined by standard methods. The influence of calcite concentrate as a filler and polyolefin elastomer as a modifier on the rheological and mechanical properties of compositions has been determined. With an increase in the amount of filler the physical and mechanical properties of the filled compositions are reduce that is offset by introducing the newest polyolefin elastomer as a modifier in amount of 5 wt. %. Addition of 5 wt. % of polyolefin elastomer in the filled composition gives them frost resistance, wherein the impact strength is higher than for compositions without the modifier even after freezing for 30 days at -18°С. It has been determined that adding of the filler does not increase the viscosity of the compositions, which contradicts the traditional behavior of filled systems. The addition of 5 wt. % of polyolefin elastomer to the filled compositions with calcite concentrate up to 20 wt.% does not change the tensile strength of the compositions which is 24 MPa, but increases elongation by 2 times, impact strength by an average of 8,5 % and frost resistance after freezing compositions at -18 °C for 30 days by an average of 12,6 %. The research results of rheological and physic-mechanical properties allow choosing the rational composition to achieve the desired characteristics of the polymer material for production goods by injection molding. Melt flow index of the compositions increases with increasing amount of filler to 50 wt. %. which does not increase the production costs of the injection molding process in comparison with unfilled compositions.