Effect of the Characteristics of Maleic Anhydride-Grafted Polypropylene (MAPP) Compatibilizer on the Properties of Highly Filled (85%) Kenaf-Polypropylene Composites

Abstract

Kenaf polypropylene composites with high fiber load of 85 wt% were produced using glycerine as a processing aid and maleic anhydride-grafted polypropylene (MAPP) as a compatibilizer/coupling agent. Commercially available MAPPs with different molecular weights and anhydride contents were used to determine what properties of the MAPPs were important to achieve high mechanical properties of these highly filled composites. A homo-polymer and a random-polymer, were compared as matrix polymers. Composites were produced using a high-shear kinetic mixer followed by compression molding at pressures ranging between 345 and 5520 kPa. The data suggests that adding MAPPs with a low molecular weight and high anhydride content at concentrations of 5 wt% resulted in composites with the highest mechanical properties. The authors suggest that a combination of a high surface area, low viscosity and high anhydride content of the MAPP are resulting in a good stress transfer between fibers and matrix polymer.

Characterization of Thermo-Mechanical and Chemical Properties of Polypropylene/Hemp Fiber Biocomposites: Impact of Maleic Anhydride Compatibilizer and Fiber Content

“…Maleic anhydride acts as a coupling agent, reacting with the hydroxyl groups present in natural fibers and forming chemical bonds with the polymer of the matrix [ 27 ]. This chemical reaction promotes greater compatibility between the polarized surfaces of the fibers and the hydrophobic polymeric matrices, resulting in a more efficient interface [ 28 ]. Additionally, the presence of functionalized maleic anhydride in the natural fibers facilitates fiber dispersion in the matrix, which contributes to an improvement in the mechanical and physical properties of composites [ 29 , 30 , 31 ].…”