The effect of surface nucleation on the crystallization of the α phase of poly(vinylidene fluoride)

1980 ◽  
Vol 51 (10) ◽  
pp. 5145 ◽  
Author(s):  
S. Weinhold ◽  
M. H. Litt ◽  
J. B. Lando
Keyword(s):  
Vinylidene Fluoride ◽  
Surface Nucleation ◽  
Α Phase ◽  
Poly Vinylidene Fluoride ◽  
Effect Of Surface

Influence of Evaporation Temperature on the Morphology, Polymorph and Mechanical Properties of Poly(vinylidene fluoride) Solution-Cast Membranes

2014 ◽  
Vol 1015 ◽  
pp. 536-539
Author(s):  
Jie Liu ◽  
Ji Ding Li ◽  
Xiao Long Lu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Vinylidene Fluoride ◽  
Dense Structure ◽  
Fluoride Solution ◽  
Evaporation Temperature ◽  
Α Phase ◽  
Poly Vinylidene Fluoride ◽  
Solution Cast ◽  
Solution Cast Method

In this study, PVDF membranes were prepared by solution-cast method. The effects of evaporation temperature on the morphology, polymorph and mechanical properties of such prepared membranes were studied. It was found that perfect spherulites were observed in the solution-cast membranes. FESEM photomicrographs of the membranes showed dense structure. PVDF mainly crystallized into α phase. In the solution-cast process, the spherulite size increased as evaporation temperature was increased from 120 °C to 150 °C, when the evaporation temperature was 165 °C, spherulite size decreased. And the tensile strength increased with the decrease in spherulite size.

The dependence of the β-to-α phase transition behavior of poly(1,4-butylene adipate) on phase separated morphology in its blends with poly(vinylidene fluoride)

2018 ◽  
Vol 20 (23) ◽  
pp. 15718-15724 ◽  
Author(s):  
Chunyue Hou ◽  
Huihui Li ◽  
Xiaoli Sun ◽  
Shouke Yan ◽  
Yanfang Wang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Vinylidene Fluoride ◽  
Phase Transition Behavior ◽  
Transition Behavior ◽  
Α Phase ◽  
Poly Vinylidene Fluoride ◽  
The Stability

Two kinds of typical phase separated morphologies are prepared and they alter the stability of crystals.

Dynamics of the field-induced transition to the polar α phase of poly(vinylidene fluoride)

1980 ◽  
Vol 51 (10) ◽  
pp. 5184 ◽  
Author(s):  
H. Dvey-Aharon ◽  
P. L. Taylor ◽  
A. J. Hopfinger
Keyword(s):  
Vinylidene Fluoride ◽  
Α Phase ◽  
Poly Vinylidene Fluoride

Preparation of poly(vinylidene fluoride)-silver nanoparticle composite using dimethylformide as both a solvent and a reductant

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Yingbo Chen ◽  
Lina Liu ◽  
Yufeng Zhang
Keyword(s):  
Mechanical Properties ◽  
Silver Nanoparticles ◽  
Silver Nanoparticle ◽  
Vinylidene Fluoride ◽  
Silver Salt ◽  
Α Phase ◽  
Phase Crystal ◽  
Poly Vinylidene Fluoride ◽  
Pure Pvdf

AbstractPoly(vinylidene fluoride)-silver nanoparticle (PVDF-Ag) composites were synthesized by in situ reduction of silver salt using dimethylformide (DMF) as both a solvent and a reductant. The crystalline properties (e.g., crystallinity and the types of crystals) of the composites were characterized. It was shown that PVDF in the composites had a higher melting temperature than pure PVDF, and the α phase crystal in the composites became more stable with an increase in the amount of silver nanoparticles. The mechanical properties and morphologies of the composites were also investigated. It was noted that the PVDF-Ag composites have better mechanical properties when silver nanoparticles were added. The increase in toughness could be attributed to the formation of continuous structure between PVDF and silver particles.

Effect of surface modifying macromolecules on the properties of poly(vinylidene fluoride) membranes

2009 ◽  
Vol 15 (3) ◽  
pp. 393-397 ◽  
Author(s):  
Dae Sik Kim ◽  
Dae Hoon Kim ◽  
Byung Seong Lee ◽  
Go Young Moon ◽  
Hyung Keun Lee ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Poly Vinylidene Fluoride ◽  
Effect Of Surface

Stretching Induced Crystalline-Phase Transition in Energy-Conversion Poly(Vinylidene Fluoride) (PVDF) Films

2014 ◽  
Vol 1070-1072 ◽  
pp. 589-593
Author(s):  
Fei Peng Wang ◽  
Zheng Yong Huang ◽  
Jian Li
Keyword(s):  
Phase Transition ◽  
Crystalline Phase ◽  
High Speed ◽  
Vinylidene Fluoride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase ◽  
Poly Vinylidene Fluoride ◽  
Crystalline Phase Transition

Commercial poly (vinylidene fluoride) (PVDF) films are uniaxially stretched with varying rates at 110 °C in order to endow PVDF piezo-and pyroelectric by crystalline-phase transition from α to β during the stretching. The crystalline phases are determined by infrared spectroscopy. The β-phase content and its fraction in films increase as a result of stretching with high rates. In addition, higher stretching rates yield a slight increase of γ phase. The crystallite size is evaluated by means of X-ray diffraction. It is found that the β-phase crystallites become smaller with fast stretching, whereas the α-phase crystallites are cracked and disappear at high-speed stretching of 2.5 /min.

Determination of the melting enthalpy of β phase of poly(vinylidene fluoride)

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Arkadiusz Gradys ◽  
Pawel Sajkiewicz
Keyword(s):  
Thermodynamic Stability ◽  
Vinylidene Fluoride ◽  
Melting Enthalpy ◽  
Dimethyl Formamide ◽  
Scanning Calorimetry ◽  
Temperature Range ◽  
Β Phase ◽  
Α Phase ◽  
Poly Vinylidene Fluoride ◽  
Limited Temperature Range

Abstract Wide Angle X-ray Scattering (WAXS), Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared spectroscopy (FTIR) analyses of phase composition and of thermal properties of PVDF samples, crystallized at temperatures 27 - 155 °C by casting from N,N-dimethyl formamide (DMF) solution, are reported. Samples obtained at 27 °C contain only β crystal phase and with increase of casting temperature content of β phase decreases in favor of α phase. Evaluation of combined: phase content (WAXS) and melting heat (DSC), leads to two fold higher than for 100 % α phase value of 100% β melting enthalpy, ΔHβ0= 219.7 J.g-1, which may be justified by strong polar interactions in β phase TTT conformation. The relation ΔHβ0 > ΔHα0 leads either to the thermodynamic stability of β phase in whole temperature range (if Tmβ0 ≥ Tmα0) or to the limited temperature range of thermodynamic stability of α phase (if Tmβ0 < Tmα0).

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