Crystallization behavior and electrical conductivity of fluorosilane-modified multi-walled carbon nanotubes/polymethyl methacrylate/polyvinylidene fluoride ternary composite

Abstract In order to increase the compatibility with polyvinylidene fluoride (PVDF), the multi-walled carbon nanotubes (MWCNTs) were modified by trimethoxy (1H, 1H, 2H, 2H heptadecafluorodecyl) silane to obtain the fluorosilane-modified MWCNTs (F-MWCNTs). The as-prepared F-MWCNTs were characterized by scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) to confirm the successful surface modification of MWCNTs by fluorosilane. The F-MWCNTs were further blended with polymethyl methacrylate (PMMA) and PVDF to prepare the MWCNTs/PMMA/PVDF ternary composites containing 1%, 3%, 5%, 7%, and 10% F-MWCNTs by solution mixing, and the as-prepared MWCNTs/PMMA/PVDF composites were characterized SEM, WAXD, FTIR, and alternating current (AC) electrical conductivity testing. It was confirmed that the F-MWCNTs were homogeneously distributed in the PMMA/PVDF matrix. Moreover, the existence of F-MWCNTs contributed to the improvement of the crystallization degree ( X c ) and β crystalline content [ F ( β )] of PVDF as well as the AC electrical conductivity ( σ AC ) for the MWCNTs/PMMA/PVDF composites. The values of X c , F ( β ), and σ AC at 100 Hz of the MWCNTs(10%)/PMMA/PVDF composite were 47.4%, 56.5%, and 2.40 × 10 –1 Sm −1 , respectively, while the corresponding values of pure PVDF were only 42.2%, 27.8%, and 1.85 × 10 –9 Sm −1 , respectively. The enhanced performances of MWCNTs/PMMA/PVDF composites in comparison with those of pure PVDF can be attributed to the interface interactions among F-MWCNTs, PVDF, and PMMA as well as the phase separation of PMMA and PVDF.