Effect of X-ray radiation on the structure of P (VDF/TrFE) copolymers

Cunha, Helenilza Ferreira Albuquerque; Mattoso, L. H. C.; Faria, Roberto Mendonça

doi:10.1002/(sici)1099-0488(199706)35:8<1201::aid-polb5>3.0.co;2-w

Cited by 11 publications

(7 citation statements)

References 3 publications

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“…These radicals can be positively or negatively charged species. The formation of radicals involves bond cleavage, such as chain scission and/or hydrogen elimination, cross‐linking by a recombination reaction, or other side‐reactions, such as double‐bond formation 11. In the present work for unfilled PVDF films, it is thought that free radicals (accumulated near the crystallite boundaries) dislocate the neighbouring atoms from their crystal sites.…”

Section: Resultsmentioning

confidence: 82%

Physical properties and β‐phase increment of AgNO₃‐filled poly(vinylidene fluoride) films

Tawansi

Oraby

Badr

et al. 2004

Polymer International

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X-ray diffraction (XRD), infrared (IR) transmition and optical absorption (OA) spectra, differential thermal analysis (DTA), dc electrical resistivity (ρ), magnetic susceptibility (χ) and electron spin resonance (ESR) of AgNO 3 -filled poly(vinylidene fluoride) (PVDF) films, were measured over the filler mass fraction range 0.001 ≤ W ≤ 15%. XRD and IR analysis evidenced the increase of α-and β-PVDF crystalline phases due to the AgNO 3 filler. The maximum crystallinity increment was found at W = 0.5%. Three endothermic peaks were detected by DTA, and were attributed subsequently to: the first order para-para-electric phase transition, the first-order ferro-para-electric phase transition and the melting. The melting peak was used to calculate the order of reaction and the activation energy of melting. The observed OA peaks and/or plateau were attributed to the charge-transfer complex formed mainly by the AgNO 3 filler. This assumption was supported by the diamagnetic susceptibility detected for the present system. The temperature dependence of ρ was explored according to a previously proposed one-dimensional interpolaron-hopping model. The hopping distance was formulated numerically as a function of temperature and filling level. The ESR findings were attributed to the roles of AgNO 3 and dimethylformamide solvent in complex formation.

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Section: Resultsmentioning

confidence: 82%

Physical properties and β‐phase increment of AgNO₃‐filled poly(vinylidene fluoride) films

Tawansi

Oraby

Badr

et al. 2004

Polymer International

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“…The formation of radicals involves bond cleavage, such as chain scission and/or hydrogen elimination, which may lead to a decrease in polymer molecular weight, crosslinking by recombination reaction, or other side reactions, such as double bond formation. 4 In the present work, it is thought that free radicals (accumulated near the crystallite boundaries) dislocate the neighboring atoms out of their crystal sites. This builds up a shell of deformed pattern in the outermost zone of the crystallite, which reduces the effective crystalline volume.…”

Section: X-ray Diffractionmentioning

confidence: 84%

“…4 In this type of cleavage, even though the energy available largely exceeds the amount required to cleave any bond, the bonds are not broken at random. PVDF, as a multiphase material, exhibits certain physical properties resulting from crystalamorphous interfacial effects.…”

Section: Introductionmentioning

confidence: 99%

Effect of NA-light radiation on the optical gap and crystal structure of AgNO3-diffused PVDF sensor

Tawansi

Oraby

Ahmed

et al. 1998

J. Appl. Polym. Sci.

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A casting method was used to prepare polyvinylidene fluoride (PVDF) and 1 wt % MnCl 2 -filled PVDF films. AgNO 3 was allowed to diffuse through the filled films. The 3 types of the prepared films were irradiated by Na light with various doses. The post-irradiation and relaxation effects were investigated using ultraviolet-visible spectroscopy, X-ray analysis, and optical microscopy. The results were interpreted on the bases of a theoretical model previously suggested for a build-up and decay of radiationinduced conductivity associated with the transition of charge carriers in the presence of a uniform trap distribution. Various structures were proposed for the diffused AgNO 3 before and after irradiation. It was found that the induced change in optical gap, due to 5-min irradiation time for the AgNO 3 diffused films, exhibits no relaxation phenomenon. Accordingly, this film can be used in photorecording applications.

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“…The large remnant polarization in the normal ferroelectric PVDF and P(VDF‐ co ‐TrFE) renders a small discharged energy density at zero electric field although the polymers display a high saturation electric displacement (∼0.1 C/m 2 ). Two ways have been successfully developed to reduce the remnant polarization via introducing defects in the crystalline phase of polymer films with either high energy irradiation or copolymerizing with a third bulk monomer . Comparing with irradiation method, the polymer prepared via introducing the third monomer such as chlorotrifluoroethylene (CTFE), chlorodifluoroethylene (CDFE), hexafluoropropylene (HFP), and internal unsaturation as defects into P(VDF‐ co ‐TrFE) may decrease their crystal domain size and crystallinity effectively, which is expected to provide the resultant polymer of high material stability, uniformity, and processing convenience.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of unsaturation containing P(VDF‐co‐TrFE‐co‐CTFE) from P(VDF‐co‐CTFE) in one‐pot catalyzed with Cu(0)‐based single electron transfer living radical polymerization system

Tan

Gao

et al. 2014

J. Polym. Sci. Part A: Polym. Chem.

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Poly(vinylidene fluoride-co-trifluoroethylene-co-chlorotrifluoroethylene) (P(VDF-co-TrFE-co-CTFE)) with internal double bond has been reported with high dielectric constant and energy density at room temperature, which is expected to serve as a promising dielectric film in high pulse discharge capacitors. An environmentally friendly one-pot route, including the controllable hydrogenation via Cu(0) mediated single electron transfer radical chain transfer reaction (SET-CTR) and dehydrochlorination catalyzed with N-containing reagent, is successfully developed to synthesize P(VDF-co-TrFE-co-CTFE) containing unsaturation. The resultant polymer was carefully characterized with 1 H NMR, 19 F NMR, and FTIR. The composition of the resultant copolymer is strongly influenced by reaction conditions, including the reaction temperature, catalyst concentration, the types of ligands and solvents. The kinetics data of the chain transfer and elimination reaction demonstrate their wellcontrolled feature of the strategy. By shifting the equilibrium between the CTR and elimination reactions dominated by Ncompounds serving as ligands in SET-CTR and catalyst in the dehydrochlorination of P(VDF-co-CTFE), P(VDF-co-TrFE-co-CTFE) with tunable TrFE and double-bond content could be synthesized in this one-pot route.

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Effect of X-ray radiation on the structure of P (VDF/TrFE) copolymers

Cited by 11 publications

References 3 publications

Physical properties and β‐phase increment of AgNO₃‐filled poly(vinylidene fluoride) films

Physical properties and β‐phase increment of AgNO₃‐filled poly(vinylidene fluoride) films

Effect of NA-light radiation on the optical gap and crystal structure of AgNO3-diffused PVDF sensor

Synthesis of unsaturation containing P(VDF‐co‐TrFE‐co‐CTFE) from P(VDF‐co‐CTFE) in one‐pot catalyzed with Cu(0)‐based single electron transfer living radical polymerization system

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Effect of X-ray radiation on the structure of P (VDF/TrFE) copolymers

Cited by 11 publications

References 3 publications

Physical properties and β‐phase increment of AgNO3‐filled poly(vinylidene fluoride) films

Physical properties and β‐phase increment of AgNO3‐filled poly(vinylidene fluoride) films

Effect of NA-light radiation on the optical gap and crystal structure of AgNO3-diffused PVDF sensor

Synthesis of unsaturation containing P(VDF‐co‐TrFE‐co‐CTFE) from P(VDF‐co‐CTFE) in one‐pot catalyzed with Cu(0)‐based single electron transfer living radical polymerization system

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Physical properties and β‐phase increment of AgNO₃‐filled poly(vinylidene fluoride) films

Physical properties and β‐phase increment of AgNO₃‐filled poly(vinylidene fluoride) films