Comparative study of different carbon reinforcements at different length scales on the properties of polyvinyl alcohol composites

Comparative studies on the mechanical behavior of the composites of polyvinyl alcohol (PVA) polymer with different carbon fillers such as multiwalled carbon nanotube (MWCNT), functionalized CNT (f‐CNT), and short carbon fiber (C f ), having similar geometry (1D) but different length scale, have been carried out. Microstructural analysis reveals better distribution of second phases with f‐CNT and C f compared with MWCNT. Fourier‐transform infrared spectra indicate the interaction of functional groups of CNTs with the polymeric chain of PVA. X‐ray diffraction analysis shows improvement of crystallinity upon addition of carbon filler. Defect analysis of carbon reinforcement is carried out using Raman spectroscopy. The strength of the composite is increased by 138% with MWCNT reinforcement, by 201.8% with f‐CNT reinforcement, and by 87.9% with C f reinforcement. The fractographs show pullout, branching, and bridging as strengthening mechanisms for MWCNT and f‐CNT in the PVA matrix, whereas mainly pullout as strengthening mechanism for C f –PVA composite.