The effects of γ-radiation on polyacrylonitrile

Hill, David J. T.; Lang, A.P.; O’Donnell, James H.; Pomery, Peter J.

doi:10.1016/0141-3910(92)90114-k

Cited by 33 publications

(17 citation statements)

References 11 publications

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“…9 The irradiation can generate free radicals in PAN, which aids crosslinking and cyclization. Radical‐induced cyclization and intermolecular crosslinking through the nitrile groups have been reported for PAN via ion beam, 10 X‐ray, 11, 12 gamma, 13–15 and UV irradiation. 10, 16 The research of Dietrich indicated that electron beam irradiation on PAN precursor fibers could generate free radical, 17 but the effect of electron beam on the stabilization process was not studied.…”

Section: Introductionmentioning

confidence: 99%

Effect of electron beam irradiation on polyacrylonitrile precursor fibers and stabilization process

Yuan

Wang

Liu

et al. 2011

J of Applied Polymer Sci

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The electron beam was imposed on the polyacrylonitrile precursor fibers before the fibers were stabilized. The effect of electron beam irradiation on the chemical structure, transverse section, and surface morphology and thermal properties of the fibers in the process of stabilization was characterized by the use of Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and differential scanning calorimeter, respectively. A parameter g ¼ I(C¼ ¼N)/[I(C¼ ¼N) þ I(CBN)] was defined to evaluate the extent of cyclization in the stabilization process. The kinetic parameters, viz. activation energy (E) and pre-exponential factor (A) of the stabilization reactions, were calculated by Kissinger method. FTIR analysis indicated that the cyclization of nitrile groups was initiated at room temperature by electron beam irradiation. The transformation of CBN groups to C¼ ¼N ones was accelerated in the process of stabilization. The extent of cyclization of the stabilized fibers was increased. SEM analysis indicated that irradiation could also decrease the internal and surface defects of the stabilized fibers treated at 300 C. The activation energy of cyclization reaction was reduced from 302 to 280 kJ/mol and 260 kJ/mol through 100 and 200 kGy electron beam irradiation, respectively. The reaction temperature range was expanded, and the exothermic rate was slowed down in the process of stabilization, which was the reason why the stabilized fibers have improved cyclization degree and less internal defects.

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Section: Introductionmentioning

confidence: 99%

Effect of electron beam irradiation on polyacrylonitrile precursor fibers and stabilization process

Yuan

Wang

Liu

et al. 2011

J of Applied Polymer Sci

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“…The situation may become more complicated when radiation with higher LET (alpha particles for instance) is applied. [20][21][22] Irradiation of PAN, either by gamma radiation2oy21 or X-rays, promotes the abstraction of No significant differences between the action of both types of radiation were observed.…”

Section: Radiation Stability Of Panmentioning

confidence: 99%

Evaluation of polyacrylonitrile (PAN) as a binding polymer for absorbers used to treat liquid radioactive wastes

Šebesta¹,

John²,

Motl³

et al. 1995

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The chemical and radiation stability of polyacrylonitrile (PAN) in the form of beads (B-PAN), similar to the beads of composite absorbers, and one selected composite absorber (ammonium molybdophosphate, the active component in PAN binder [AMP-PAN], a prospective candidate for the treatment of acidic wastes) were studied. Aqueous 1M HN03 + 1M NaN03, 1M NaOH + 1M NaN03, and 1MNaOH were chosen as simulants of DOE acidic and alkaline wastes. In addition, radiation stability was determined in distilled water. The chemical stability of B-PAN and AMP-PAN beads was tested for a period up to one month of contact with the solution at ambient tem erature. The radiation stability of the beads was checked in a radiation dose range lo3 -10 Gy (lo5 -10' rads).In acidic solutions the stability of PAN binder was proved not to be limited by either chemical or radiation decomposition. PAN binder may thus be used for preparing composite absorbers for treatment of acid wastes from DOE facilities. The same conclusion is valid for alkaline solutions with pH up to 13.In highly alkaline solutions (concentration of NaOH higher than 1 M) and in the presence of NaN03, the stability of the tested polyacrylonitrile polymer was sufficient for applications not extending over 10 days. Cross-linking of the polymer caused by ionizing radiation was found to have a positive influence on chemical stability. This effect enables a longer period of applicability of PAN-based composite absorbers. Because of the high sorption rate achievable with PAN-based absorbers, the stability achieved is sufficient for most applications in the DOE complex. The chemical stability of binding polymer may also be further improved by testing another, more suitable type of polymer fiom the broad family of polyacrylonitrile polymers.

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“…268 Kubota and Kimura 282 evaluated the effect of various solvents on PE degradation and radicals formed. 286 Radicals were identified and the effect of dose evaluated for -irradiated PTFE. Degradation of model compounds depends also on the excitation method.…”

Section: Electron Spin Resonancementioning

confidence: 99%

Testing Methods of Weathered Specimen

Wypych¹

2013

Handbook of Material Weathering

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The effects of γ-radiation on polyacrylonitrile

Cited by 33 publications

References 11 publications

Effect of electron beam irradiation on polyacrylonitrile precursor fibers and stabilization process

Effect of electron beam irradiation on polyacrylonitrile precursor fibers and stabilization process

Evaluation of polyacrylonitrile (PAN) as a binding polymer for absorbers used to treat liquid radioactive wastes

Testing Methods of Weathered Specimen

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