Polypropylene composites was made within two different type of fillers and a coupling agent to improve its mechanical properties. The composite was used for injection process. Injection temperature, injection pressure, injection speed, injection pause time, cooling time and all conditions of the composites were controlled accurately. Mechanical properties of charpy impact strength, tensile strength, elongation to break and hardness are studied. Composites of PP/Talc (10%) and PP/CaCO3 (10%) were selected as combinations due to having the optimum of the mechanical properties. A ternary composite of PP (90%)+Talc(5%)+ CaCO3 (5%) which was studied show an impact strength as high as the pure PP. To improve the mechanical properties of the composite a maleic anhydride grafted polypropylene copolymer was used which unfortunately showed a negative effects on the mechanical properties, particularly on impact strength, the most important factor of the project. To improve the effect of maleic anhydride (1 w% to 5 w%) as a suitable coupling agent, was added to the composites. Impact strength of the composite was increased as much as 100 percent compare to PP/Talc (10%) and PP/CaCO3 (10%) composites and 20 percent increases compeer to PP itself.

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