Influence of the processing method on the properties of a PVDF film

Abstract

The main electrophysical properties of polyvinylidene fluoride (PVDF) films produced by two technologies: the solution casting method and the method of hot pressing from the melt are investigated. To analyze the PVDF films, methods of dielectric spectroscopy (DS), IR spectroscopy, TGA/DSC analysis, and x-ray diffraction (XRD) are used. It is demonstrated that the IR spectra of both PVDF films change weakly in comparison with the virgin PVDF film. The absorption bands characteristic for α-, β-, and γ-phases are observed for the virgin and both types of PVDF films. This testifies to the fact that the molecular structure of film samples is practically independent of their processing method. The only difference is that the new absorption band at 1723 cm -1 arises in the IR spectra of the films produced by the method of hot pressing from the melt. The TGA/DSC analysis demonstrates that the beginning melting temperature, melting temperature, beginning decomposition temperature, and decomposition temperature for the film samples produced by the method of hot pressing from the melt decrease by 8, 2, 10, and 12°C, respectively, compared to the film samples produced by the solution casting method.

A Novel Li+‐Conducting Polymer Membrane Gelled by Fluorine‐Free Electrolyte Solutions for Li‐Ion Batteries

“…This confirms that LiBOB is effectively dissociated in the room temperature samples because of the presence of the carbonates. In the spectra of the thermally treated samples, the bands of the α ‐phase PVdF are no more detectable, while new signals appeared (specifically at 882 and 1082 cm −1 ), that are assigned to the polar TTGG conformation of β ‐phase PVdF . This suggests that during the heating treatment of samples, a rearrangement in the crystalline phase of PVdF (from α to β phase) occurs, and a part of the samples possibly becomes amorphous as represented by the broaden bands of the heated samples.…”

Spectroscopic Studies of Nanocomposites Based on PEO/PVDF Blend Loaded by SWCNTs

“…The peaks which due to β-phase of PVDF at 2θ = 20.10˚ (1 1 0) and 36.96˚ (2 0 0) which disappear with adding the filler. For PVDF phases, the peaks at 2θ = 19.09˚ (020) and 39.71˚ (002) for α-phase, at 2θ = 20.01˚ (110 or 200) and 35.48˚ (001) for β-phase and at 2θ = 26.17˚ (022) for γ-phase are founded [28] [29]. There are two peaks are observed at 2θ ≈ 18.33˚ and 23.25˚ corresponding to (120) and (112) attributed to crystallite forms of PEO [30].…”

Treeing resistance parameters of polymeric dielectrics

“…The destruction rate both at the induction stage and the tree growth stage can be reduced due to the change of the main mechanical strain not only in the vicinity of the needle tip but also along all insulating gap. It has been shown earlier [3,5,6] that the transverse-longitudinal direction of the melt flow direction allows both the tree inception time and the breakdown time for the PC samples to be increased by 80% and 30% respectively compared to the samples with longitudinal direction of the melt flow.…”

“…Properties of thermoplastic polymers can be changed in wide range not only depending on the type, chemical structure, and sub-molecular structure but also processing parameters [1][2][3][4][5][6][7]. When polymers are under a high temperature for a long time, the destruction or oxidation of macromolecules will take place.…”