Electrical conductivity and mechanical properties, free volume, and γ‐ray transmission of ethylene propylene diene monomer/butadiene rubber composites

Hamed, Mohamed; Taha, Howayda G.; Alaa, Hossam B.

doi:10.1002/pc.25464

Cited by 11 publications

(21 citation statements)

References 80 publications

(84 reference statements)

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“…It is clear from the figure that, the correlation is linear and the σ DC increases with the increasing of the free volume size indicating that the ionic conductivity of NaI/PVA composites is controlled by the free volume size. This behavior is similar to that obtained data by Mohamed et al 80 for the unirradiated samples of different concentrations of the polybutadiene rubber in ethylene propylene diene monomer. In addition, it is consistent with the reported measurements by El‐Gamal et al 81 found that the ionic conductivity of the polymeric sample increases with the increasing of the free volume as a result of the addition of polyaniline to PVA.…”

Section: Resultssupporting

confidence: 91%

Study of the nanostructure of free volume and ionic conductivity of polyvinyl alcohol doped with NaI

Hmamm

Zedan

Hamed

et al. 2020

Polymers for Advanced Techs

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Positron annihilation lifetime (PAL), AC conductivity, and impedance spectroscopy have been applied for the investigation of polyvinyl alcohol (PVA) doped with different concentrations of NaI in the range from zero to 25 wt%. Wide‐angle x‐ray diffraction measurements reveal that the addition of NaI to the PVA structure leads to a decrease in the crystallinity of the sample. The free volume size obtained from PAL measurements increases with the increase of the NaI concentration on PVA. NaI acts as an inhibitor of positronium formation on the doped polymer with inhibition constant of 0.028 (Mol%)−1. The ionic conductivity of the investigated sample was found to be correlated with the free volume size, which indicates the major role of free volume in the conduction mechanism. The AC conductivity of the prepared samples is measured at room temperature in the frequency range from 50 Hz to 5 MHz. The calculated values of frequency exponent s indicate the hopping mechanism in ionic conductivity. Impedance spectroscopy of PVA doped with different concentrations of NaI was studied. The appeared semi‐circle, in the Nyquist plot, denotes the bulk influence of PVA with different concentrations of NaI. This has been attributed to the parallel connection of bulk resistance and bulk capacitance. Also, the semi‐circle radius of Cole‐Cole plots was found to decrease with the increase of the concentration ratio (wt%) of NaI. So, the increase of the conductivity of PVA with the increase of NaI contents has been investigated.

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Section: Resultssupporting

confidence: 91%

Study of the nanostructure of free volume and ionic conductivity of polyvinyl alcohol doped with NaI

Hmamm

Zedan

Hamed

et al. 2020

Polymers for Advanced Techs

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“…The frequency ranged from 50 Hz to 5 MHz, and the measurements began at that point. The out‐of‐plan of the AC proton conductivity σ AC can be obtained as, 22,23

Proton conductivity σ_{AC} ((), normalS / normalm) goodbreak= \frac{L normalG}{A} .

where L and A is the membrane thickness and the cross‐sectional area of the electrodes, respectively.…”

Section: Methodsmentioning

confidence: 99%

Humidity effect on the transport properties of per‐fluorinated sulfonic acid/PTFE proton exchange membranes: Positron annihilation study

El-Sharkawy

Mohamed

Hassanien

et al. 2021

Polymers for Advanced Techs

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The positron annihilation lifetime (PAL) technique was used to investigate the yield and lifetime of positronium (Ps) in three different samples of per‐fluorinated sulfonic acid/polytetrafluoroethylene (PTFE) proton exchange membranes. The high probability of Ps formation enables the study of the hole volume size by the PAL technique and explains the mechanism of both methanol permeation and proton conductivity of the membranes in relation to the relative humidity (RH). The influence of various membrane parameters, including water uptake, proton conductivity, and mechanical properties, was studied. The concentration of water molecules and SO3−–H3O+groups is correlated with the ion exchange capacity (IEC) of the membranes where higher IEC leads to high absorbance of water. The proton conductivity is enhanced by increasing the IEC value of the membrane. The activation energies of decomposition temperature for the F‐950 membrane are the lowest (Eb = 2.856 and 1.030 eV for the 1st and 2nd decomposition peaks, respectively, implying that the membrane with high IEC is thermally less stable. With increasing the IEC of the membranes, the concentration of the water molecules/SO3 group increases. In addition, the proton conductivity of the membrane is positively influenced by increasing water content at high RH. The fact that the variations in hole volume size and both methanol permeability and proton conductivity are highly dependent on RH suggests that hole volume size plays an important role in many parameters of hydrated perfluorinated sulfonic acid/PTFE proton exchange membranes. The outcomes data were introduced and interpreted appropriately with a theoretical model and compared with the literature.

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“…On the other hand, polymer-filler interface might cause in the absorption of the polymer chains on the filler surface and reduces its progress. Consequently, the polymer viscosity and modulus will be increased [46,47].…”

Section: Tensile Test Measurementsmentioning

confidence: 99%

Effect Of Carbon Black Loading On Linear Low-Density Polyethylene Properties

Al‐Qahtani

Al‐Ejji

Ouederni³

et al. 2021

Preprint

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The mechanical, thermal, electrical, reheology, and morphological properties of composites made from linear low-density polyethylene and carbon black (CB) content of 5%, 10%, and 20% by weight were investigated. The optimum mechanical and electrical properties performance was achieved with the adding of 5% carbon black. The drop in properties after adding more CB is due to agglomeration and poor dispersion of carbon particles in the polymer matrix. CB resulted in higher dynamic viscosity and storage modulus at low frequencies, although this phenomenon was reversed at high frequencies. CB resulted in more shear thinning of LLDPE at high shear rates.

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Electrical conductivity and mechanical properties, free volume, and γ‐ray transmission of ethylene propylene diene monomer/butadiene rubber composites

Cited by 11 publications

References 80 publications

Study of the nanostructure of free volume and ionic conductivity of polyvinyl alcohol doped with NaI

Study of the nanostructure of free volume and ionic conductivity of polyvinyl alcohol doped with NaI

Humidity effect on the transport properties of per‐fluorinated sulfonic acid/PTFE proton exchange membranes: Positron annihilation study

Effect Of Carbon Black Loading On Linear Low-Density Polyethylene Properties

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