Study of Epoxy Based GFRP Nanocomposites Modified With Polymer Fiber Elastomer

Abstract

Commercially used epoxy based glass fiber reinforced polymer composites (epoxy based GFRPs) show good specific strength and stiffness and are employed in many structural applications. However, safe operation of structures for the required lifetime demands that in addition to good static mechanical properties, these composites also possess high impact strength. Among the various approaches studied for an improvement in impact strength of epoxy based composites, significant efforts have been made by addition of nanoclay or polymer/elastomer fillers. Addition of nanoclay is reported to improve almost all properties of epoxy, but the impact strength has not shown significant improvements. Further, addition of elastomers to GFRPs is reported to show significant toughening of epoxy but other properties such as tensile strength etc. show significant deterioration. So, literature reports that addition of nanoclay leads to significant improvements in static properties and addition of polymer/elastomer filler leads to improved toughness of epoxy. Therefore, a combination of both, nanoclay and polymer/elastomer filler in epoxy based GFRPs, may provide a new route for high impact strength along with good tensile properties. Thus, in the present work, epoxy based GFRP nanocomposites reinforced with clay as the nanofiller and thermoplastic fibers/elastomer particles as the micro-filler were processed using vacuum assisted hand lay-up technique. Polymer fibers namely polypropylene (PP) fibers and polyethylene terephthalate (PET) fibers, and an elastomer namely ethylene propylene diene monomer (EPDM) particles were used separately as the second filler in GFRPs containing nanoclay as the first filler. Nanoclay was added in a fixed amount of 1 phr in various nanocomposites. Low concentration of clay was chosen in order to avoid excessive increase in viscosity of the resulting system on addition of polymer/elastomer micro-fillers along with clay.