Free volume evolution in polyoxymethylene studied by positron annihilation spectroscopy

Abdel-Hady, E.E.; Hamed, Mohamed; Fareed, Somia S.

doi:10.1016/j.radphyschem.2006.03.018

Cited by 6 publications

(2 citation statements)

References 18 publications

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“…It is clear that, at low electron irradiation fluence, σ is increased linearly with increasing FFV. As many free‐volume theory supposes that free volume is responsible for electrical conduction in polymers 30,31 . With further increase of electron irradiation fluence, FFV diminished, and consequently the AC conductivity decreased.…”

Section: Resultsmentioning

confidence: 96%

Electron irradiation induced molecular changes in PMMA: A positron spectroscopy study

Awad

Alkureda

Abdel-Hady

et al. 2020

Polymers for Advanced Techs

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To examine the positron annihilation parameters with regard to microstructural changes, the positron annihilation lifetime spectroscopy and measurements of the Doppler broadening of annihilation radiation (DBAR) of electron‐irradiated poly(methyl methacrylate) were carried out at room temperature. Trapping rate equations were applied in terms of the positron bulk lifetime as well as the positron lifetime fitting results to investigate the molecular changes due to electron irradiation effects. It was found that the mean positron lifetime shows the same trend as the o‐Ps intensity. In disordered regions, the positronium trapping rate suggests that trapping of o‐Ps increases with increasing electron irradiation fluence until electron fluence reached 5.9 × 1013 electrons/cm2, after which it begins to decrease. The line shape S‐parameter was found to have similar behavior as the o‐Ps intensity, and suggests that poly(methyl methacrylate) undergoes chain scission, followed by cross‐linking, and eventually degradation, due to the electron radiation effects. The results of positron annihilation spectroscopy were verified by X‐ray results, mechanical, and electrical measurements.

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Section: Resultsmentioning

confidence: 96%

Electron irradiation induced molecular changes in PMMA: A positron spectroscopy study

Awad

Alkureda

Abdel-Hady

et al. 2020

Polymers for Advanced Techs

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“…A polycarbonate track detector such as Makrofol offers an easy way of detecting the tracks formed by heavy charged particles . These polymers are insensitive to light particles such as X‐rays and gamma rays; so, using heavy charged particles the modification in the various properties of these polymers can be studied.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study of the Effects of Oxygen Ions Upon the Free Volume and Physico‐Chemical Properties of Makrofol (KG & N) Polycarbonate

Gupta

Singh

Awasthi

et al. 2015

Macromolecular Symposia

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Summary: Makrofol (KG & N) polymers are the important class of polycarbonates which are used as solid state nuclear track detectors. The effect of 100 MeV oxygen ions (O 7þ ) on the free volume and physico-chemical properties of Makrofol (KG & N) polymers were studied. The pristine and irradiated samples were characterized by positron annihilation lifetime spectroscopy, X-ray diffraction, UV-visible and FTIR. A comparative study of free volume was carried out from the obtained values of the pristine and irradiated samples of both the polymers. The absorption edges of UV-visible were found to be shifted towards longer wavelength region. The intensities of the various absorption bands of the infrared spectra were found to be modified; which indicated the changes in the chemical properties of the exposed samples.

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Phonons and heat capacity of polyoxymethylene

Srivastava

et al. 2011

J of Applied Polymer Sci

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Free volume evolution in polyoxymethylene studied by positron annihilation spectroscopy

Cited by 6 publications

References 18 publications

Electron irradiation induced molecular changes in PMMA: A positron spectroscopy study

Electron irradiation induced molecular changes in PMMA: A positron spectroscopy study

A Comparative Study of the Effects of Oxygen Ions Upon the Free Volume and Physico‐Chemical Properties of Makrofol (KG & N) Polycarbonate

Phonons and heat capacity of polyoxymethylene

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