Nano, micro and multiscale filler-reinforced functionalized polypropylene composites: FTIR characterization and mechanical study

Nano, micro and hybrid filler-reinforced polypropylene (PP) composites were prepared via melt compounding technique using a twin screw extruder. The nano scale MWCNTs and micro scale glass fibers were used as reinforcements. In addition to the individual effect of nano and micro scale reinforcements in virgin PP, the dual effect of multiscale (MWCNT/glass fiber) fillers was also elucidated. Morphological images revealed the effectiveness of dispersion of the fillers in the matrix and it was observed that the functionalized composites showed increased filler dispersion. The static mechanical properties of the non-functionalized and functionalized samples were compared and the hybrid composite with 2 wt.% MWCNTs showed the highest tensile strength without modulus reduction. The strong bonding between carboxyl-treated MWCNTs and maleic anhydride-grafted PP was well revealed in the FTIR spectra. In hybrid composites, the effect of silane-treated glass fibers was revealed and the siloxane linkages occurred between the glass fiber surface and silanol groups were confirmed by the FTIR spectra.