Crystallization kinetics of PVDF filled with multi wall carbon nanotubes modified by amphiphilic ionic liquid

Abstract

The special electric properties of the poly(vinylidene fluoride) (PVDF) is strongly dependent on its crystalline structural morphology. In this study, modification in the crystal structure of PVDF was achieved by utilizing the long alkyl chain ionic liquid (1-hexadecyl-3-methylimidazolium bromide, [C 16 mim][Br]) and ionic liquid modified multiwalled carbon nanotubes (MWCNT). The developed crystal pattern was analyzed by XRD and the compatibility and dispersion characteristics of MWCNT in the matrix was observed by FESEM. The isothermal and non-isothermal crystallization kinetics were studied by DSC and different models namely; Avrami, Jeziorny and Ozawa were applied to fit the data. The results demonstrate that crystal structure of PVDF is significantly changed and the dispersion of MWCNT was enhanced with the addition of ionic liquid (IL). Kinetically, the crystallization was influenced and became fast due to the presence of [C 16 mim][Br] at the PVDF/MWCNT interface. Furthermore, the data well fitted in the model with significant linearity. The positive effect on the crystallization of PVDF may be ascribed to not only due to the existence of -cation interaction between the imidazolium cation and the aromatic multiwall carbon nanotubes structure, but also due to the electrostatic interaction between the > CF 2 of the polymer backbone and imidazolium cation, which speed up the crystallization kinetics.

Crystallization behaviors of poly(vinylidene fluoride) and poly(methyl methacrylate)-block-poly(2-vinyl pyridine) block copolymer blends

“…5, it is found that the higher the cooling rate, the shorter the time of crystallization completion which is similar to previous non-isothermal crystallization studies [40]. Avrami's method is widely used to study the crystallinity under isothermal conditions [41][42][43][44][45]. The Avrami equation is expressed as…”

Non-isothermal crystallization kinetics of polypropylene/short glass fibre/multiwalled carbon nanotube composites

“…To extend the application of Avrami model to non-isothermal crystallization characteristics of polymers Jeziorny 24 modified the model assuming that non isothermal crystallization is a synergy of infinitesimally small isothermal steps. The modified Avrami model can be represented by eqn (9) and crystallization rate constant Z c could be evaluated.…”

Progress in Ionic Liquids as Reaction Media, Monomers and Additives in High-Performance Polymers

“…The crystal structure of PVDF was modified by utilising the long alkyl chains of [C 16 mim][Br] and IL-modified MWCNTs, and the crystallisation kinetics of the composites was investigated [126,127]. A series of PVDF composites with 'bucky gels' of MWNTs and ILs were obtained by simple melt compounding.…”