Comparisons of phase morphology and physical properties of PVDF nanocomposites filled with organoclay and/or multi-walled carbon nanotubes

Abstract

Binary and ternary poly(vinylidene fluoride) (PVDF) nanocomposites filled with organoclay (15A) and/or multi-walled carbon nanotubes (MWNTs) were successfully prepared. MWNTs were dispersed more homogeneously than 15A within PVDF matrix, and the presence of MWNTs facilitated the dispersibility of 15A. The 15A addition induced β-form PVDF crystal formation, but MWNTs hardly changed the α-form crystal development. Both nanofillers facilitated the nucleation of PVDF (up to 12.3 °C increase), and the efficiency of enhancing PVDF crystallization followed the sequence MWNT > 15A/MWNT > 15A. The nanocomposites possess higher Tm° than neat PVDF. In particular, adding 15A led to a Tm° (β-form) increase of no less than 11 °C. A rheological percolation threshold at 1 wt.% MWNT loading was determined. The electrical resistivity dropped by more than 13 orders of magnitude at 5 wt.% MWNT loading. The nanocomposites exhibited enhanced tensile modulus (up to 83% increase with MWNTs inclusion) compared with neat PVDF.