A comparison of two different methods for formation of the beta phase in nanocomposites based on vinylidene fluoride-hexafluoropropylene copolymer

Abstract

Nanocomposite materials based on vinylidene fluoride-hexafluoropropylene copolymer and organically modified montmorillonite Cloisite ® 15A were prepared by two different methods: melt mixing and co-precipitation. The changes taking place in crystalline structure, tensile strength, thermal behavior and the formation of piezoelectric β -phase as a result of the polymer system dissolution in dimethyl sulfoxide were studied. The technological specificity of each method has certain effect on the properties of the obtained nanocomposites. The highest content of β -phase -95 % was achieved by co-precipitation from the solution of vinylidene fluoride-hexafluoropropylene copolymer in dimethyl sulfoxide and 6 mass % content of Cloisite ® 15A. Despite the common view that the use of solvents and prolonged technological procedure lead to overall higher expenses, the obtained nanocomposites could be promising for the preparation of new piezo-materials.

High Temperature Resistant Separator of PVDF-HFP/DBP/C-TiO2 for Lithium-Ion Batteries

“…The asymmetrical and symmetrical stretching vibrations of CF 2 are present at 1179 and 1282 cm −1 [22]. Meanwhile, the peak for β-phase of PVDF-HFP appears at 873 cm −1 [32,33]. In general, these are characteristic peaks of PVDF-HFP, and they are consistent with the results of the following XRD spectrum analysis.…”

Tunable polarization components and electric field induced crystallization in polyvinylidenefluoride: A piezo polymer

“…The β phase of PVDF is thermodynamically meta-stable phase with all trans (TTTT) zigzag chain conformation. 7,27 PVDF exhibits ferroelectric property as its electric dipole due to C-F and C-H can be changed in the presence of external electric field, 17 which is confirmed by the ferroelectric hysteresis loop. The SS (Switching spectroscopy)-PFM studies performed in all the samples at various locations confirm the presence of ferroelectric hysteresis with switching characteristics.…”

“…Since our interest is mainly on understanding the ferroelectric domains of pure PVDF with its semicrystalline nature we continued our studies with PVDF and not sticking to the methods known to enhance the β-phase. 1,27,29,30,31,32,33 From above characterization we can conclude that the PVDF films in consideration mainly consists of β-phase along with minor fraction of other γ phase. Fig.…”

“…The peak at 2θ = 20•2 which is relative to the sum of diffraction from the planes 200 and 110 confirms the presence of β-phase in PVDF films and the shoulder peak at 18•5 corresponding to 020 plane which indicate the existence of small percentage of γ-phase. 1,4,10,25,26,27 The films prepared from varying viscosities seem to have no change in the percentage of mixed phases present, however a minor enhancement in the crystallinity of PVDF films was observed when synthesized from higher viscous solutions. Fig.…”

Experimental investigation on mechanical and microstructural behaviour of GFRP elastomeric nanocomposites

“…Clay dispersion in the rubber matrix was well observed by scanning electron microscope. 44,45 From SEM results it has been clearly observed that for most of the specimens clay particles were uniformly intercalated in the matrix along with the presence of some white inclusions. This is due to the improper mixing of clay particles within the ethylene propylene diene elastomer matrix.…”