Performance of talc/ethylene‐octene copolymer/polypropylene blends

Polypropylene‐based compounds are increasingly attractive because of low cost, processability, and good balance of properties. In recent years, metallocene ethylene‐octene copolymers have started displacing EPR and EPDM as an impact modifier for PP. This study examines the effect of compounding conditions and composition on the properties of talc/ethylene‐octene copolymer/PP compounds. The mechanical properties of the compounds were not significantly affected by the mixing conditions on a laboratory twin screw extruder. The use of 30 wt% of talc provided a twofold increase in tensile modulus compared with pure PP. Impact resistance of filled and unfilled compounds was found to increase rapidly once the copolymer concentration reached around 20 wt% based on the polymer phase. Modulus and tensile strength decreased linearly with copolymer concentration. Four different commercial maleic anhydride‐grafted PPs were tested as interfacial modifiers. In the best cases, a slight tensile strength increase was observed when using between 2 and 10 wt% of modified PP.