Effect of Coupling Agents on the Performance of PP/MAH-g-PP/CaCO₃Ternary Composites

This study deals with the creation and characterization of a polypropylene/calcium carbonate composite in the presence of maleic anhydride–grafted polypropylene used as a compatibilizer. In order to improve the properties of the interfacial zones, the reinforcing filler was treated with two different coupling agents, which were a silane named Dow Corning Z-6020 and a zirconate coupling agent named Ken-React NZ-44. The performance of the interface within the composites was assessed through the measurement of the mechanical and thermal properties. The results revealed an important enhancement of the impact strength and the heat deflection temperature as a result of surface treatment. The analysis of the relative evolution of those properties showed that a more pronounced reinforcing effect was obtained with the NZ-44 coupling agent. The improvement in the properties seemed to depend particularly on the state of the dispersion of the filler throughout the matrix and on the nature of the interface. The thermogravimetric analysis allowed the conclusion that the filler improved the thermal stability of the material but the coupling agent did not seem to have any influence on this property.