Kinetics of isothermal and non-isothermal crystallization of poly(vinylidene fluoride) by fast scanning calorimetry

Polymer ◽  
2016 ◽  
Vol 82 ◽  
pp. 40-48 ◽  
Author(s):  
A. Gradys ◽  
P. Sajkiewicz ◽  
E. Zhuravlev ◽  
C. Schick
Keyword(s):  
Isothermal Crystallization ◽  
Vinylidene Fluoride ◽  
Scanning Calorimetry ◽  
Fast Scanning Calorimetry ◽  
Poly Vinylidene Fluoride ◽  
Kinetics Of

scholarly journals Characteristics of the Non-Isothermal and Isothermal Crystallization for the β Polymorph in PVDF by Fast Scanning Calorimetry

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2708
Author(s):  
Ernesto Pérez ◽  
Irene Angulo ◽  
Enrique Blázquez-Blázquez ◽  
María L. Cerrada
Keyword(s):  
Isothermal Crystallization ◽  
Vinylidene Fluoride ◽  
Polymer Science ◽  
Scanning Calorimetry ◽  
Isothermal Conditions ◽  
Β Phase ◽  
Fast Scanning Calorimetry ◽  
Poly Vinylidene Fluoride ◽  
The One ◽  
Very High

Structuring at very high rates has become one of the current and important topics of interest in polymer science, because this is a common protocol in the processing of films or fibers with industrial applicability. This work presents the study by fast scanning calorimetry, FSC, of poly(vinylidene fluoride), paying special attention to the conditions for obtaining the β phase of this polymer, because it is the one technologically more interesting. The results indicate that this β phase of poly(vinylidene fluoride) is obtained when the sample is isothermally crystallized at temperatures below 60 °C. Under non-isothermal conditions, the β polymorph begins to be observed at rates above 400 °C/s, although a coexistence with the α modification is observed, so that exclusively the β phase is obtained only at rates higher than 3000 °C/s.

scholarly journals Graphene Nanoplatelet-Reinforced Poly(vinylidene fluoride)/High Density Polyethylene Blend-Based Nanocomposites with Enhanced Thermal and Electrical Properties

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 361 ◽  
Author(s):  
Kartik Behera ◽  
Mithilesh Yadav ◽  
Fang-Chyou Chiu ◽  
Kyong Rhee
Keyword(s):  
Isothermal Crystallization ◽  
High Density Polyethylene ◽  
Vinylidene Fluoride ◽  
High Density ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Graphene Nanoplatelet ◽  
Polyethylene Blend ◽  
Poly Vinylidene Fluoride ◽  
Mixing Method

In this study, a graphene nanoplatelet (GNP) was used as a reinforcing filler to prepare poly(vinylidene fluoride) (PVDF)/high density polyethylene (HDPE) blend-based nanocomposites through a melt mixing method. Scanning electron microscopy confirmed that the GNP was mainly distributed within the PVDF matrix phase. X-ray diffraction analysis showed that PVDF and HDPE retained their crystal structure in the blend and composites. Thermogravimetric analysis showed that the addition of GNP enhanced the thermal stability of the blend, which was more evident in a nitrogen environment than in an air environment. Differential scanning calorimetry results showed that GNP facilitated the nucleation of PVDF and HDPE in the composites upon crystallization. The activation energy for non-isothermal crystallization of PVDF increased with increasing GNP loading in the composites. The Avrami n values ranged from 1.9–3.8 for isothermal crystallization of PVDF in different samples. The Young’s and flexural moduli of the blend improved by more than 20% at 2 phr GNP loading in the composites. The measured rheological properties confirmed the formation of a pseudo-network structure of GNP-PVDF in the composites. The electrical resistivity of the blend reduced by three orders at a 3-phr GNP loading. The PVDF/HDPE blend and composites showed interesting application prospects for electromechanical devices and capacitors.

Influence of the Crystallization Kinetics on the Microstructural Properties of γ-PVDF

2008 ◽  
Vol 587-588 ◽  
pp. 534-537 ◽  
Author(s):  
M.P. Silva ◽  
Vitor Sencadas ◽  
A.G. Rolo ◽  
Gabriela Botelho ◽  
Ana Vera Machado ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Optical Microscopy ◽  
Kinetic Parameters ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Vinylidene Fluoride ◽  
Microstructural Properties ◽  
Infrared Transmission ◽  
Poly Vinylidene Fluoride ◽  
Kinetics Of

The kinetics of the isothermal crystallization of the γ-phase Poly(vinylidene fluoride) has been investigated. Samples were prepared from the melt at different crystallisation temperatures and the variation of the microstructure of the samples was monitored with time by optical microscopy. Raman and Infrared transmission spectroscopies also show the appearance of the γ-phase for higher crystallisation temperatures. Two types of γ-phase spherulites have been identified. These spherulites represents different ways to obtain the γ-phase and show different thermal stability. The correlation between microstructure and kinetic parameters allows the tailoring of the microstructure by choosing the crystallisation conditions of the samples.

scholarly journals Effect of Poling on the Mechanical Properties of β-Poly(Vinylidene Fluoride)

2006 ◽  
Vol 514-516 ◽  
pp. 951-955 ◽  
Author(s):  
Carlos M. Costa ◽  
Vitor Sencadas ◽  
João F. Mano ◽  
Senentxu Lanceros-Méndez
Keyword(s):  
Mechanical Properties ◽  
Mechanical Response ◽  
Vinylidene Fluoride ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Direction Parallel ◽  
Poly Vinylidene Fluoride ◽  
The Stability ◽  
Kinetics Of ◽  
The Degree Of Crystallinity

In this work, mechanical and thermal experimental techniques have been applied in order to relate the mechanical response with the microscopic variations of the material. Stress-strain results along the main directions of β-poly(vinylidene fluoride), β-PVDF, in poled and non-poled samples enables to investigate the influence of the poling process on the mechanical response of the material. Further, differential scanning calorimetry experiments allow the investigation of the effect of poling in the degree of crystallinity of the material as well as on the stability of the crystalline phase. Thermogravimetric analysis was used to investigate the kinetics of the thermal degradation of poled and non-poled β-PVDF samples. The differences observed between the two materials suggest that the poling affects the mechanical properties of the material especially in the direction parallel to the polymeric chains and originates changes at a molecular level that remain beyond the melting of the material.

scholarly journals Gelation of Poly(Vinylidene Fluoride) Solutions in Native and Organically Modified Silica Nanopores

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 3025 ◽  
Author(s):  
Alejandra Espinosa-Dzib ◽  
Sergey Vyazovkin
Keyword(s):  
Vinylidene Fluoride ◽  
Tetraethylene Glycol ◽  
Modified Silica ◽  
Scanning Calorimetry ◽  
Chain Mobility ◽  
Organically Modified ◽  
Poly Vinylidene Fluoride ◽  
Organically Modified Silica ◽  
Kinetics Of ◽  
Kinetics Of Gelation

The purpose of this study is to highlight the surface and size effects of the nanopores on the thermodynamics and kinetics of gelation. The effects have been probed by applying differential scanning calorimetry to poly(vinylidene fluoride) solutions in tetraethylene glycol dimethyl ether (tetraglyme) and γ-butyrolactone. Nanoconfinement has been accomplished by introducing gels into native and organically modified silica nanopores (4–30 nm). Nanoconfinement has produced two major effects. First, the heat of gelation has decreased three to four times compared to that for the bulk systems. Second, the temperature of gelation has increased by ~40 °C (tetraglyme based systems) and ~70 °C (γ-butyrolactone based systems), the increase being stronger in native nanopores. The effects are discussed in terms of acceleration of gelation due to heterogeneous nucleation at the confining surface, and retardation of gelation due to constricted polymer chain mobility in the middle of the pore volume. Calorimetric data have been subjected to isoconversional kinetics analysis. The obtained temperature dependencies of the activation energies of gelation have been interpreted in the frameworks of the nucleation model of Turnbull and Fisher. The results suggest that nanoconfinement leads to a lowering of both the free energy of nucleation and activation energy of diffusion.

scholarly journals Thermal Properties and Non-Isothermal Crystallization Kinetics of Poly (δ-Valerolactone) and Poly (δ-Valerolactone)/Titanium Dioxide Nanocomposites

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 452 ◽  
Author(s):  
Waseem Saeed ◽  
Abdel-Basit Al-Odayni ◽  
Abdulaziz Alghamdi ◽  
Ali Alrahlah ◽  
Taieb Aouak
Keyword(s):  
Titanium Dioxide ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Three Dimensional ◽  
Degree Of Crystallinity ◽  
Simultaneous Occurrence ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics ◽  
The Stability ◽  
Kinetics Of

New poly (δ-valerolactone)/titanium dioxide (PDVL/TiO2) nanocomposites with different TiO2 nanoparticle loadings were prepared by the solvent-casting method and characterized by Fourier transform infra-red, differential scanning calorimetry, X-ray diffraction and scanning electron microscopy, and thermogravimetry analyses. The results obtained reveal good dispersion of TiO2 nanoparticles in the polymer matrix and non-formation of new crystalline structures indicating the stability of the crystallinity of TiO2 in the composite. A significant increase in the degree of crystallinity was observed with increasing TiO2 content. The non-isothermal crystallization kinetics of the PDVL/TiO2 system indicate that the crystallization process involves the simultaneous occurrence of two- and three-dimensional spherulitic growths. The thermal degradation analysis of this nanocomposite reveals a significant improvement in the thermal stability with increasing TiO2 loading.

Simulations of High-Strain Electrostrictive Chlorinated Terpolymers

2003 ◽  
Vol 785 ◽  
Author(s):  
George J. Kavarnos ◽  
Thomas Ramotowski
Keyword(s):  
Vinylidene Fluoride ◽  
High Strain ◽  
Polymer Chains ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lamellar Structures ◽  
Annealing Conditions ◽  
Poly Vinylidene Fluoride ◽  
Electromechanical Responses ◽  
Kinetics Of

ABSTRACTChlorinated poly(vinylidene fluoride/trifluoroethylene) terpolymers are remarkable examples of high strain electrostrictive materials. These polymers are synthesized by copolymerizing vinylidene fluoride and trifluoroethylene with small levels of a third chlorinated monomer. The electromechanical responses of these materials are believed to originate from the chlorine atom, which, by its presence in the polymer chains and by virtue of its large van der Waals radius, destroys the long-range crystalline polar macro-domains and transforms the polymer from a normal to a high-strain relaxor ferroelectric. To exploit the strain properties of the terpolymer, it is desirable to understand the structural implications resulting from the presence of the chlorinated monomer. To this end, computations have been performed on model superlattices of terpolymers using quantum-mechanical based force fields. The focus has been on determining the energetics and kinetics of crystallization of the various polymorphs that have been identified by x-ray diffraction and fourier transform infrared spectroscopy. The chlorinated monomer is shown to act as a defect that can be incorporated into the lamellar structures of annealed terpolymer without a high cost in energy. The degree of incorporation of the chlorinated monomer into the crystal lattice is controlled by annealing conditions and ultimately determines the ferroelectric behavior of the terpolymers.

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