Experimental assessment of mechanical behavior of basalt/graphene/PP-g-MA-reinforced polymer nanocomposites by response surface methodology

The present study investigates the mechanical and morphological properties of polypropylene (PP)-based nanocomposites reinforced with basalt fiber, graphene nanosheets, and polypropylene-grafted maleic anhydride (PP-g-MA) using Box-Behnken design and response surface methodology (RSM). Using an internal mixer and hot press compression, the reinforcements were added to the matrix at three levels, including 0, 0.75, and 1.5 wt% graphene nanosheets, 0, 7.5, and 15 wt% basalt fiber, and 0, 3, and 6 wt% PP-g-MA. The fiber length was 5 mm and kept fixed for all samples. The samples were subjected to tensile, flexural, and impact tests to obtain the optimum levels of reinforcements. The results of RSM revealed that while the inclusion of graphene nanosheets at 1 wt% improved the tensile, flexural, and impact strength by 15%, 11%, and 16%, respectively, its further inclusion at 1.5 wt% weakened these properties. The incorporation of graphene nanosheets at 1.5 wt% improved the elastic modulus by 69%. Adding basalt fibers to 15 wt% improved the elastic modulus, tensile, flexural, and impact strength by 27%, 85%, 10%, and 8%, respectively. The incorporation of PP-g-MA enhanced the graphene nanosheet/basalt fiber adhesion to the matrix, dispersion, and compatibility, resulting in improved tensile strength and elastic modulus by 18% and 71%, respectively. Based on RSM analysis, adding PP-g-MA to 5 wt% improved the flexural strength by 8% and impact strength by 5% while its further addition to 6 wt% decreased these properties. The samples were also monitored by FE-SEM to assess the dispersion of each of the reinforcements in the polymeric matrix.

Automated summary

This study investigates the mechanical and morphological properties of polypropylene-based nanocomposites reinforced with basalt fiber, graphene nanosheets, and polypropylene-grafted maleic anhydride. The results show that the inclusion of graphene nanosheets at 1 wt% improves the tensile, flexural, and impact strength, while further inclusion at 1.5 wt% weakens these properties. Adding basalt fibers to 15 wt% improves the elastic modulus, tensile, flexural, and impact strength. The incorporation of PP-g-MA enhances the graphene nanosheet/basalt fiber adhesion to the matrix, resulting in improved tensile strength and elastic modulus.