Thermal analysis for study of the gamma radiation effects in poly(vinylidene fluoride)

Medeiros, A.S.; Gual, Maritza Rodríguez; Pereira, Cláubia; Faria, Luiz Roberto Ribeiro

doi:10.1016/j.radphyschem.2015.05.006

Cited by 25 publications

(13 citation statements)

References 10 publications

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“…The initial decomposition temperature of the thermogram for the irradiated films reveals a gradual decrease in melting temperatures ( T m ) and a shift toward the lower end with dose, confirming the change in molecular structure as well as decreased weight of polymer electrolyte is a result of the creation of free radical via oxidative degradation process leading to increase in the amorphousity and decrease in crystalline region at high EB dosage. 12,29 Hence, these results confirm the influence of irradiation and are well agreed with the obtained XRD results.…”

Section: Resultssupporting

confidence: 90%

Modified Thermal, Dielectric, and Electrical Conductivity of PVDF-HFP/LiClO₄Polymer Electrolyte Films by 8 MeV Electron Beam Irradiation

et al. 2018

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The polymer electrolyte films (poly((vinylidene fluoride)- co -hexafluoropropylene)/LiClO 4 @90:10 w/w, PHL10) were prepared by solution-casting technique and the effect of various dosages of electron beam (EB) irradiation on structure, morphology, thermal, dielectric, and conductivity properties at various dosages. The atomic force microscope topography image shows substantial change in surface morphology due to irradiation and the modification of chemical bonds through chain scission process with increased EB dose was confirmed by Fourier transform infrared spectroscopy studies. NMR studies confirm the change in structural properties due to irradiation. The X-ray diffractometer confirms the decreased crystallinity from 50.10 for unirradiated film to 40.96 at 120 kGy doses; hence, increase in amorphousity due to a decrease in melting temperature from 460 to 418 °C leads to the degradation of the polymer, and the differential scanning calorimetry study reveals the decreased crystallinity with increased irradiation dose. The dielectric and modulus parameters are observed to decrease with increasing frequency as well as temperature. The conductivity increases with frequency and EB dose due to the increased segmental motion of charged ions by chain scission/cross-linking process. The high conductivity of 1.81 × 10 –3 S/cm with the corresponding relaxation time of 1.697 × 10 –6 at 120 kGy dose was observed. The conduction mechanism reveals an Ohmic behavior and the I – V plot exhibits a gradual increase in current with applied voltage as well as irradiation dose. The electrochemical performance of the irradiated polymer electrolyte was improved significantly and hence the polymer electrolytes can be used in solid-state batteries and storage applications after altering the properties by the influence of irradiation.

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Section: Resultssupporting

confidence: 90%

Modified Thermal, Dielectric, and Electrical Conductivity of PVDF-HFP/LiClO₄Polymer Electrolyte Films by 8 MeV Electron Beam Irradiation

et al. 2018

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“…Additionally, the EB radiation can reduce the tensile strength of the films due to chain scission [ 287 ].

-radiation has been similarly demonstrated to cause chain scission in cross-linked structures, such as by Medeiros et al [ 288 ]. Owing to PVDF’s wastewater filtration uses, radiation changes of this nature are a potential problem.…”

Section: Pvdf Stabilitymentioning

confidence: 99%

On the Solubility and Stability of Polyvinylidene Fluoride

et al. 2021

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This literature review covers the solubility and processability of fluoropolymer polyvinylidine fluoride (PVDF). Fluoropolymers consist of a carbon backbone chain with multiple connected C–F bonds; they are typically nonreactive and nontoxic and have good thermal stability. Their processing, recycling and reuse are rapidly becoming more important to the circular economy as fluoropolymers find widespread application in diverse sectors including construction, automotive engineering and electronics. The partially fluorinated polymer PVDF is in strong demand in all of these areas; in addition to its desirable inertness, which is typical of most fluoropolymers, it also has a high dielectric constant and can be ferroelectric in some of its crystal phases. However, processing and reusing PVDF is a challenging task, and this is partly due to its limited solubility. This review begins with a discussion on the useful properties and applications of PVDF, followed by a discussion on the known solvents and diluents of PVDF and how it can be formed into membranes. Finally, we explore the limitations of PVDF’s chemical and thermal stability, with a discussion on conditions under which it can degrade. Our aim is to provide a condensed overview that will be of use to both chemists and engineers who need to work with PVDF.

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“…Previous results obtained by Emi-Reynolds et al [4] and Thembinkosi [7] were scaled to present activity for the facility and compared to measurements taken. The results are presented in Table 1.…”

Section: Comparison Of Practical Resultsmentioning

confidence: 99%

“…Gamma Irradiation Laboratory is mostly used for several applications like enhancing or altering molecular structure and other properties of polymers [4], altering gemstone color [5], and others.…”

Section: Introductionmentioning

confidence: 99%

Dose Rate Assessment at a Gamma Processing Facility in Ghana

Sackey¹,

Banini²,

Emi-Reynolds³

et al. 2020

Int. j. appl. phys. sci.

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This study was carried out to verify the adequacy of the shielding mechanisms in place at the Gamma Irradiation Facility (now Radiation Technology Centre) of the Ghana Atomic Energy Commission to ensure that workers of the facility are not over-exposed to radiation in routine work as prescribed by the local authority and international regulations. A category IV Wet Storage Gamma Irradiation Facility, Ghana Atomic Energy Commission, Accra Ghana. The duration of the study was six months. Use of Rad-Eye G-10 Thermo Scientific Gamma Survey Meter to measure dose rate around the biological shield of a Co-60 source (activity of 27.4kCi, was in the irradiation position) at controlled areas of the facility, which included control room, electrical power room, deionizer room, the roof of irradiation chamber (specifically roof plugs) and two entrances to the irradiation chamber (the personnel door and the goods door). Background reading was 0.08 ± 0.01µSv/h. Radiation dose rates at the Personnel door and the goods door were 0.090µSv/h and 0.109µSv/h, respectively. Practical measurements at the roof plugs produced average values of 0.135µSv/h. A particular point on Plug-3 produced a relatively higher reading of 8.151µSv/h. Measurements in the control room, electrical room, and deionizer room gave average readings of 0.116µSv/h, 0.089µSv/h, and 0.614µSv/h, respectively. All average values were below the limits of 7.5µSv/h and 50mSv/yr. Total radiation at the entrances of the mazes is due mainly to scattered radiation. The shielding by lead doors (0.009m) and concrete walls (1.6 m-1.9m) of the installed 1.85 PBq (50kCi) rectangular plaque Co-60 source irradiation chamber are sufficient to shield occupationally exposed workers at the facility when the source is in the storage position and operation. The dose limit of 7.5µSv/h (i.e., 50mSv per year) is not exceeded. The presence of an entrance maze (8.1m and 9.1m) is also adequate and contributes to multiple scattering. The visual and audio warning mechanisms and interlock systems are satisfactory and adequate, provided the facility is operated safely to prevent over-exposure. Shielding calculations (in particular for the deionizer room) would need to be carried out before such an upgrade to a 500kCi source.

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Thermal analysis for study of the gamma radiation effects in poly(vinylidene fluoride)

Cited by 25 publications

References 10 publications

Modified Thermal, Dielectric, and Electrical Conductivity of PVDF-HFP/LiClO₄Polymer Electrolyte Films by 8 MeV Electron Beam Irradiation

Modified Thermal, Dielectric, and Electrical Conductivity of PVDF-HFP/LiClO₄Polymer Electrolyte Films by 8 MeV Electron Beam Irradiation

On the Solubility and Stability of Polyvinylidene Fluoride

Dose Rate Assessment at a Gamma Processing Facility in Ghana

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Thermal analysis for study of the gamma radiation effects in poly(vinylidene fluoride)

Cited by 25 publications

References 10 publications

Modified Thermal, Dielectric, and Electrical Conductivity of PVDF-HFP/LiClO4Polymer Electrolyte Films by 8 MeV Electron Beam Irradiation

Modified Thermal, Dielectric, and Electrical Conductivity of PVDF-HFP/LiClO4Polymer Electrolyte Films by 8 MeV Electron Beam Irradiation

On the Solubility and Stability of Polyvinylidene Fluoride

Dose Rate Assessment at a Gamma Processing Facility in Ghana

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Product

Resources

About

Modified Thermal, Dielectric, and Electrical Conductivity of PVDF-HFP/LiClO₄Polymer Electrolyte Films by 8 MeV Electron Beam Irradiation

Modified Thermal, Dielectric, and Electrical Conductivity of PVDF-HFP/LiClO₄Polymer Electrolyte Films by 8 MeV Electron Beam Irradiation