Hybrid Polyvinylidene Fluoride/Nanoclay/MWCNT Nanocomposites: PVDF Crystalline Transformation

In this work the coexistence effect of Cloisite 30B and multi-walled carbon nanotubes(MWCNT) on the crystal transformation of the polyvinylidene fluoride (PVDF) matrixis reported. It was found that at a constant rate of 3% (by weight) total modification,a higher percentage of beta crystal was evolved in PVDF matrix as compared with thatof 3% (by weight) of each nanomaterial in the whole nanocomposite system. Thesechanges in the crystalline structure were quantitatively and qualitatively studied usingFTIR and WXRD techniques, respectively. The FTIR technique confirmed the formationof 80%, 71% and 84% of beta crystal for the three prepared composites. Thesmall-angle X-ray scattering (SAXS) technique revealed a 10-time increase in thed-spacing of the nanoclay in nanocomposites as compared with that in raw nanocaly.The morphology of the nanomaterials and the state of dispersion were investigatedusing SEM and TEM techniques. The synergism observed was assigned to differencesin surface conformations and aspect ratio of the nanomaterials. These nanocompositesensured formation of beta crystals without any need to apply strain. Meanwhile, thepiezoelectric constant (d33) of the hot-pressed samples was found to be zero. To attainpiezopyroelectric characteristics, there was a need to cold-drawing, probably by smallerstrain which resulted in better mechanical properties and anisotropy of the resultinghybrid nanocomposite