Effect of fast neutrons on dielectric properties of pure and gelatin doped-poly (vinyl alcohol) films

Abo‐Ellil, M. S.; Gaafer, S.A.; El‐Kader, F. H. Abd; Kamel, Nagwa A.

doi:10.1007/s10965-006-0114-z

Cited by 13 publications

(11 citation statements)

References 9 publications

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“…The calculated electric dipole moments for the PVA and glycogen homopolymers and their blends with compositions of 85/15, 70/30, 50/50, and 30/70 w/w PVA/glycogen were 23.1, 31.6, 19.8, 17.6, 21.4, and 20.6 D, respectively. The value of μ o for PVA was in good agreement with that previously reported 17. Interestingly, the value of μ o for the blend samples was lower than that for the individual polymers.…”

Section: Resultssupporting

confidence: 91%

Effects of the composition ratio, eosin addition, and γ irradiation on the dielectric properties of poly(vinyl alcohol)/glycogen blends

El‐Kader

Gaafar

Mahmoud

et al. 2008

J of Applied Polymer Sci

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ABSTRACT:The dielectric relaxation spectra of various poly(vinyl alcohol) (PVA)/glycogen blends and irradiated blend samples with 70 wt % PVA content that were undoped and doped with eosin were measured in extended temperature (30-1608C) and frequency (1 kHz to 1 MHz) ranges. Dielectric relaxation spectroscopy separates different molecular groups of a repeating unit of a polymer with respect to the rate of its orientation dynamics. In the high-temperature range (>1008C), the r relaxation, which is associated with the hopping motion of ions in the disordered structure of the biopolymeric material, can be measured. The electric dipole moment and the activation energy of the glass-transition temperature relaxation process were calculated.

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Section: Resultssupporting

confidence: 91%

Effects of the composition ratio, eosin addition, and γ irradiation on the dielectric properties of poly(vinyl alcohol)/glycogen blends

El‐Kader

Gaafar

Mahmoud

et al. 2008

J of Applied Polymer Sci

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“…The ε value (1.4938) is maximum at a frequency of 20 Hz and at a DC bias potential of 10 V. With a further increase in the frequency and DC bias potential, the ε value decreases. This behavior can be attributed to the decrease in the chain space and the free‐volume dipoles in the PVA polymer network due to the increasing concentration of gelatin 40. Tan −1 A of the 90/10 PVA/gelatin blend film is shown in Figure 15.…”

Section: Resultsmentioning

confidence: 98%

“…In this study, the electrical properties of PVA/gelatin blend films were studied. Variations in ε, the dielectric loss (tan −1 A ), and other electrical parameters give rise to structural changes in the polymer matrix due to the presence of gelatin 40. Figure 6 shows a plot of ε for the PVA film.…”

Section: Resultsmentioning

confidence: 99%

Preparation and characterization of poly(vinyl alcohol) and gelatin blend films

Pawde

Deshmukh

Parab

2008

J of Applied Polymer Sci

115

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Poly(vinyl alcohol) (PVA) is a water-soluble polymer that has been studied intensively because of several interesting physical properties that are useful in technical applications, including biochemical and medical applications. In this article, we report the effects of the addition of gelatin on the optical, microstructural, thermal, and electrical properties of PVA. Pure and PVA/gelatin blend films were prepared with the solution-casting method. These films were further investigated with Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, and dielectric measurements. The FTIR spectrum shows a strong chemical interaction between PVA and gelatin molecules with the formation of new peaks. These peaks are due to the presence of gelatin in the blend films. The DSC results indicate that the addition of gelatin to PVA changes the thermal behavior, such as the melting temperature of PVA, and this shows that the blends are compatible with each other. This also shows that the interaction of gelatin and PVA molecules changes the crystallite parameters and the degree of crystallinity, and this supports the XRD results. The UV-vis optical study also reflects the formation of the complex and its effect on the microstructure of the blend film. Moreover, the addition of gelatin also gives rise to changes in the electrical properties of PVA/gelatin blend films.

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“…The results of dielectric constant (ε′ ) and loss factor (ε″) and conductivity (σ ac ) properties depending on the temperature at fixed frequency (1 kHz) are summarized in Table a and b. The temperature coefficient of permittivity (TCP) was estimated from room temperature, T r , up to the glass transition temperature, T g , according to the following equation:

TCP = \frac{1}{ε_{normalmp}^{'}} \frac{d {normalε}^{'}}{d T}

where dε′ is the difference between dielectric constant at T g and T r , d T = T g − T r ,

ε_{normalmp}^{'}

is the dielectric constant at the midpoint. The dielectric constants at T g (=60°C) and room temperature are 5.99 and 3.46, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The results of dielectric constant (ε′) and loss factor (ε″) and conductivity (σ ac ) properties depending on the temperature at fixed frequency (1 kHz) are summarized in Table 1a and b. The temperature coefficient of permittivity (TCP) was estimated from room temperature, T r , up to the glass transition temperature, T g , according to the following equation [24] :…”

Section: Dielectric Measurementsmentioning

confidence: 99%

Characterization, thermal behavior, and electrical measurements of poly[4‐(2‐bromoisobutyroyl methyl)styrene]

Biryan

Demirelli

2017

Adv Polym Technol

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The 4-(2-bromoisobutyroyl methyl)styrene [BBMS] monomer was synthesized. The homopolymer of BBMS was prepared by free radical polymerization method. The decomposition behavior of P(BBMS) was thermally investigated by thermogravimetric analysis (TGA). For thermal decomposition kinetics of poly(BBMS), Flynn-Wall-Ozawa method was applied to thermogravimetry curves. The first step, which is one of the two decomposition stages, is comprehensively related to elimination of hydrogen bromide and the other step is related to a multi-step process. The activation energy (E a ) of thermal decomposition of the first step and 50% weight loss is 148.5 and 190.7 kJ/mol, respectively. The results showed that the side group elimination without chain breaking comprehensively proceeded at lower temperature, and at progressive temperatures subsequently the specific chain scission did so. Degradation of poly(BBMS) did not lead to depolymerization. 1 H, 13 C-NMR, and FT-IR analyses showed that the decomposition products during degradation of poly(BBMS) to 260°C were comprehensively HBr and methacrylic acid. Electrically conducting graphene-based poly(BBMS) composites were prepared. The DC and AC electrical measurements of graphene-based poly(BBMS) composites were carried out. The AC dielectric measurements of poly(BBMS) were investigated up to 70°C between 100 Hz and 20 kHz depending on the alternating current conductivities. The dipolar functional groups (C-O, C=O, and Br) of the BBMS segment possesses significantly affect the dielectric constant. Also, the activation energy profile of different graphene/ poly(BBMS) composites were revealed by measuring DC conductivity of individual composite material. K E Y W O R D S characterization, electrical properties, poly(BBMS), thermal behavior | 1995 BIRYAN YANnd ndDEBIDEEB F I G U R E 1 (a) 1 H-NMR and (b) 13 C NMR spectra of monomer(BBMS) [Colour figure can be viewed at wileyonlinelibrary. com] How to cite this article: Biryan F, Demirelli K. Characterization, thermal behavior, and electrical measurements of poly[4-(2-bromoisobutyroyl methyl) styrene].

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Effect of fast neutrons on dielectric properties of pure and gelatin doped-poly (vinyl alcohol) films

Cited by 13 publications

References 9 publications

Effects of the composition ratio, eosin addition, and γ irradiation on the dielectric properties of poly(vinyl alcohol)/glycogen blends

Effects of the composition ratio, eosin addition, and γ irradiation on the dielectric properties of poly(vinyl alcohol)/glycogen blends

Preparation and characterization of poly(vinyl alcohol) and gelatin blend films

Characterization, thermal behavior, and electrical measurements of poly[4‐(2‐bromoisobutyroyl methyl)styrene]

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