Isothermal Melt Crystallization Kinetic Behavior of Poly (vinylidene fluoride)
Authors
Abstract:
Isothermal melt crystallization kinetics of PVDF was investigated by differential scanning calorimetry. Thin PVDF film has been fabricated by the solvent casting technique using dimethylformamide (DMF). Then, the samples were melted and subsequently crystallized in the range of the crystallization temperature (Tc) between 138 and 145 °C. The crystallization kinetics was derived from Avrami equation. Avrami parameter (n) was found in a range from 1.5 to 2.4 and the values of the crystallization rate parameters (k) increased with decreasing Tc. So the crystallization rate parameters suggested that PVDF crystallize slower with increasing of Tc. The Hoffman–Weeks equation has used to approximate the equilibrium melting point of PVDF which was concluded to be 182 °C. Likewise, the activation energy was estimated to be 103.2 kJ/mol for isothermal crystallization. In this research, Lauritzen- Hoffmann theory was employed to analyze crystallization kinetics. Accordingly, regime "I" found appropriate to describe the present case of PVDF crystallization.
similar resources
Effect of Preparation Methods on Crystallization Behavior and Tensile Strength of Poly(vinylidene fluoride) Membranes
Poly(vinylidene fluoride) (PVDF) membranes were prepared by non solvent induced phase separation (NIPS), melt spinning and the solution-cast method. The effect of preparation methods with different membrane formation mechanisms on crystallization behavior and tensile strength of PVDF membranes was investigated. Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and ...
full textCrystallization of Poly(ε-caprolactone) in Poly(vinylidene fluoride)/Poly(ε-caprolactone) Blend
The crystallization behavior of poly(ε-caprolactone) (PCL) in a poly(vinylidene fluoride) (PVDF)/PCL blend as well as on a highly orientated PVDF substrate was studied by means of POM, DSC and TEM. The results show that the miscibility of the PVDF/PCL blend and the spherulitic morphology of PVDF varies with the blend ratio. For all the compositions, the pre-existing PVDF crystals accelerated th...
full textThe Effect of Chain Structures on the Crystallization Behavior and Membrane Formation of Poly(Vinylidene Fluoride) Copolymers
The crystallization behaviors of two copolymers of PVDF were studied, and the effect of copolymerized chains on the crystallization behavior was investigated. The results indicated that both copolymers had a lowered crystallization temperature and crystallinity. The crystallization rate was improved by the copolymer with symmetrical units in PVDF chains, but hindered by asymmetrical units, comp...
full textDensity Functional Theory calculations of the ferroelectric poly(vinylidene fluoride- chlorotrifluoroethylene) copolymer, compared to those of poly(vinylidene fluoride)
The quantum mechanics calculations of the energetics and structures corresponding to the different representatives structural conformations of poly(vinylidene fluoridetrifluoroethylene) and poly(vinylidene fluoridechlorotrifluoroethylene) copolymers show that the all-trans, Tp conformation, is energetically stabilized even with a chlorine substituent. The changes in the molecular arrangement as...
full textMy Resources
Journal title
volume 49 issue 1
pages 21- 29
publication date 2015-06-01
By following a journal you will be notified via email when a new issue of this journal is published.
Hosted on Doprax cloud platform doprax.com
copyright © 2015-2023