Compounding sequence as a critical factor in the dispersion of OMMT/hydrocarbon resin/PP-g-MA/PP nanocomposites

The properties of polyolefin nanocomposites strongly depend on the dispersion level of the nanoparticles, and the addition of dispersion agents has contributed to improvements in their performance. However, the mixing order of the components must be considered due to potential effects of each component alone. In this study, the morphology of the polypropylene nanocomposites was correlated to the preparation method, the use of hydrogenated hydrocarbon resin and the use of compatibilizing agents (PP-g-MA). The nanocomposites were prepared by intercalation of organoclay montmorillonite (OMMT) and PP-g-MA as compatibilizer with different maleic anhydride (MA) content in the molten state with either one-step or two-step mixing. A better distribution and dispersion of the OMMT platelets was achieved by using the two-step procedure. This improvement was observed to a significantly greater extent in samples with compatibilizing agents in the first mixing step. Additionally, the use of hydrogenated hydrocarbon resin showed improvement in morphology with lower MA content. These results point to the two-step method as a means to improve clay dispersion in the field of polyolefin nanocomposite processing.