Crystal Modification And Crystallization Kinetics Of PVDF Through Amphiphilic Ionic Liquid (IL)&IL/Modified MWCNT

In this work, we have prepared, the blends and nanocomposites of PVDF, with amphiphilic ionic liquid (IL),1-hexadecyl-e-methyl-imidazolium bromide ([C16MIM][Br]), and IL/modified MWCNT (different aspect ratios), respectively. The blends and nanocomposites were prepared by, solution blending method. The prepared blends and nanocomposite samples were characterized by FESEM, FTIR-ATR, XRD, POM, optical microscopy, DMA, mechanical testing machine and differential scanning calorimetry (DSC). The purpose of this work, was to study the impact of long alkyl chain imidazolium based IL and IL/modified MWCNT, on the crystallization of PVDF and its subsequent impact on the properties, of the blends and nanocomposites.The impact of IL was studied, on the crystallization, crystal structure, spherulitic growth and morphology of the blend. The amphiphilic ionic liquids modification shows unusual behavior on the crystallization of PVDF, subject to the loading amount of the IL. At 1% concentration, the behavior of IL is like a soft nucleating agent, while at high concentration (>1%) the effect is like a plasticizer. The cause of the unusual nucleating ability, of IL was found out as the formation of worm like reverse micelle at high temperature, which makes the crystallization fast. In addition, the IL produced the β/γ phase of PVDF. The POM results also confirms, the formation of non birefringent β/γ phase spherulites, while at 1% loading of the IL, the spherulites are more diffused and small in size, which shows the nucleating ability of IL. Due to the worm like reverse micelle generation, a special type of foliage-fibrilar structure of the IL, was preserved in the PVDF. The IL was then removed, from the solid film of PVDF to sees the imprint of IL, when it was in the melt state at the crystallization temperature of PVDF. The imprint clearly, shows the inter-digitated structure of the IL in the melt state, which shows the order in the IL structure even in the liquid state.To extend the work further, the MWCNT were modified with the IL and investigate its effect, on the crystallization of PVDF. The IL modification greatly increased the dispersion of MWCNT, in the polymer matrix, which appears in the form of high β/γcontents as well as high crystallization temperature. The role of the anion is also very important, and it was shown, that, crystallization profile of PVDF can be controlled using different anion of the IL. The apparent no noticeable difference in the glass transition (Tg) of the nanocomposite, confirm the miscibility of the IL with MWCNT/PVDF system. The DMA result, also reveals, the crystal transformation of PVDF due to IL presence in the nanocomposites.In addition, the effect of ionic liquid (1-hexadecyl-3-methylimidazolium bromide, [Ci6MIM][Br]) and IL-modified multiwalled carbon nanotubes, on the crystallization kinetics (both isothermal and nonisothermal) of PVDF, was concluded. The isothermal and nonisothermal data obtained from DSC, were well fitted to the Avrami, Jeziorny and Flynn-Well-Ozawa models. The presence of the ionic liquid, at the polymer-filler interface speed up the process of PVDF crystallization, which might be, due to the combined (synergistic) efforts of the ionic liquid and multiwalled carbon nanotubes (MWCNT).