Effect of High-Energy Radiation on Polypropylene

Black, Robin M.; Lyons, B. J.

doi:10.1038/1801346a0

Cited by 52 publications

(10 citation statements)

References 4 publications

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“…that intramolecular scissioning is more important in reducing the weightaverage molecular weight Bw of a broad molecular weight polymer than equivalent crosslinking is in increasing intermolecularly the @, and (2) chain branching derived from crosslinking has been found to modify the solvent interaction constants in the Mark-Houwink equation to give a smaller RSV for crosslinked than for linear material of equal molecular weight. l 3 The importance of the molecular weight distribution on radiation-induced RSV changes waa shown as follows. For high density polyethylene, previous investigators have demonstrated that irradiation gave very little chain scission and a predominance of c r o~s l i n k i n g .~~*~ Two samples of high-density polyethylene were examined for changes in RSV as a function of dose.…”

Section: Analysis Of Results Obtained On Polypropylene-additive Systemsmentioning

confidence: 99%

Molecular weight changes in irradiated polypropylene

Marans

Zapas

1967

J of Applied Polymer Sci

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W. R. GTCW and Company, Clai-ksvilk?, M a y h n d 21089 synopsisWe have shown by two separate measurements that polypropylene when melted after irradiation undergoes crosslinking from the inception of irradiation. The first proof wm an immediate increase in the solution viscosity of a narrow molecular weight fraction of polypropylene. The socond proof ww the marked change in melt-flow properties on irradiation of a broad molecular weight distribution polypropylene. These findings tend to support one of the two currently held views on the action of radiation on polypropylene. In addition we have confirmed previous reports that melting after irradiation contributes to the overall crosslinking reaction.

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Section: Analysis Of Results Obtained On Polypropylene-additive Systemsmentioning

confidence: 99%

Molecular weight changes in irradiated polypropylene

Marans

Zapas

1967

J of Applied Polymer Sci

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“…So that the cross-linking in PP=EVA blend was enhanced by alkyl radicals in PP chains and methyl radicals in EVA chains [9] . Along with alkyl radicals, the possibility of formation of vinylidene in PP segments also enhances the cross-linking [21] . This result means that PP contributes to the cross-linking in PP=EVA blends and that PP degradation is prevented in PP=EVA blends; that is, methyl radicals in EVA chains are active sites for enhancement of radiation cross-linking in PP=EVA.…”

Section: Results and Discussion Chemical Analysismentioning

confidence: 98%

“…Formation of vinylidene group indicates the cross-linking after successive chain scission reaction and it favors in the presence of EVA. A possible mechanism of a cross-linking involves the formation of a vinylidene double bond via main-chain C-C bond scission [21] .…”

Section: Results and Discussion Chemical Analysismentioning

confidence: 99%

Formation of Vinylidene in Polypropylene/Ethylene Vinyl Acetate (PP/EVA) Blends During Degradation

Alothman

Salahudeen

Elleithy

et al. 2012

Polymer-Plastics Technology and Engineering

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The effect of natural exposure and artificial weathering on selected properties of PP/EVA blends was investigated. The vinyl acetate concentration decreased with exposure time due to acetylation. The most pronounced effect of radiation is associated with oxidative degradation. The cross-linking of PP/EVA blends was attributed to the formation of vinylidene group. Weathering decreased the tensile strength, elongation at break, and Young's modulus of the naturally and artificially exposed blends. This reduction was the result of blends' molecular weight reduction due to the degradation induced by weathering.

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“…The transition to gel under irradiation (~50 Mrad) is well defined from viscosity studies (ref. 19). Radiation exposure in air is subject to oxidation and treatment is best in inert atmosphere or in vacuum.…”

Section: Improved Fiber/matrix Interfacementioning

confidence: 99%

E-beam-Cure Fabrication of Polymer Fiber/Matrix Composites for Multifunctional Radiation Shielding

Wilson

Jensen

Thibeault

et al. 2004

Space 2004 Conference and Exhibit

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Aliphatic polymers were identified as optimum radiation polymeric shielding materials for building multifunctional structural elements.Conceptual damage-tolerant configurations of polyolefins have been proposed but many issues on the manufacture remain. In the present paper, we will investigate fabrication technologies with e-beam curing for inclusion of high-strength aliphatic polymer fibers into a highly cross-linked polyolefin matrix. A second stage of development is the fabrication methods for applying face sheets to aliphatic polymer closed-cell foams.

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Effect of High-Energy Radiation on Polypropylene

Cited by 52 publications

References 4 publications

Molecular weight changes in irradiated polypropylene

Molecular weight changes in irradiated polypropylene

Formation of Vinylidene in Polypropylene/Ethylene Vinyl Acetate (PP/EVA) Blends During Degradation

E-beam-Cure Fabrication of Polymer Fiber/Matrix Composites for Multifunctional Radiation Shielding

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