Enhancement in mechanical properties of GFRP-coal-derived graphene oxide composites by addition of multiwalled carbon nanotubes and halloysite nanotubes: A comparative study

Abstract

In this study, we compare synergistic performance of two different nanofillers, namely halloysite nanotubes (HNT) clay and multiwalled carbon nanotubes (MWCNT), in conjunction with a fixed concentration (0.125 phr) of semi-anthracite coal-derived graphene oxide (AC-GO) on mechanical properties improvement of EGFPs (E-glass fiber-based epoxy resin composites). The dispersion of AC-GO with HNT clay (GO-H) and AC-GO with MWCNT (GO-C) within epoxy matrix was achieved using sonication and homogenization. Further mixture was incorporated into mats of E-glass fiber employing “vacuum-assisted resin infusion molding” (VARIM). Significant enhancements (18.3% flexural strength, 14.6% tensile strength, and a slight increase of impact strength (1.8%)) were observed in EGFPs reinforced with GO-H at 0.50 phr loading of HNT, with an AC-GO concentration maintained at 0.125 phr. Correspondingly, optimal values for GO-C reinforced EGFPs at 0.25 phr were 40.3%, 18.7%, and a 10.5% decrease in impact strength, respectively. Analytical techniques such as XRD, FESEM, EDX mapping, and FTIR reveal presence of relatively abundant functionalities and strong interfacial adhesion in GO-H as well as GO-C. The cost of HNT clay is approximately 15 times cheaper than industrial-grade MWCNTs, therefore, these results underscore potential of GO-H as a very economical nano-reinforcement alternative to GO-C for polymer nanocomposites. Highlights: 0.50 phr HAGRP improves 18.3% flexural, 14.6% tensile, 1.8% impact strengths. Beyond 0.50 phr HAGRP and 0.25 phr CAGRP, mechanical properties decreased. 0.25 phr CAGRP improves 40.3% flexural, and18.7% tensile strengths. FESEM, FTIR reveal strong interfacial adhesion between nanofillers and epoxy. GO-H has proven to be an inexpensive reinforcement for polymer nanocomposites.