Mechanical properties of exfoliated graphite nanoplatelet (XGNP) filled impact modified polypropylene nanocomposites
Publication Name: Proceedings of the 56th International SAMPE Symposium and Exhibition
In this study, we investigate the effect of particle diameter size, filler loading and coupling agent on the mechanical properties of exfoliated graphite nanoplatelet (xGnP)-filled impact modified polypropylene (IMPP) nanocomposites. xGnP-filled IMPP nanocomposites were prepared at 2, 4, 6, and 8 wt. % xGnP with and without the addition of a coupling agent. The coupling agent used in this study was polypropylene-graft-maleic anhydride (PP-g-MA). The nanoparticles used were xGnP with three different sizes: xGnP 5 has an average thickness of 10 nm, and an average platelet diameter of 5 ?m, whereas xGnP 15 and xGnP 25 have the same thickness but average diameters are 15 and 25 ?m, respectively. Test results show that nanocomposites with smaller xGnP diameters exhibited better mechanical properties. For composites containing a coupling agent, tensile modulus increased with the addition of xGnP. In the case of neat composites, tensile modulus decreased at higher filler loading levels. Increasing xGnP loading level resulted in reduction of elongation at break for both neat IMPP and IMPP composites with coupling agent. Moreover, unnotched and notched impact strengths were dramatically deteriorated with the introduction of xGnP. Explanation of this brittle behavior is presented using melt flow index, scanning electron microscopy and transmission electron microscopy.