Crystallinity and the effect of ionizing radiation in polyethylene. I. Crosslinking and the crystal core

Journal Article · Sat Feb 01 04:00:00 EST 1975 · J. Polym. Sci., Polym. Phys. Ed., v. 13, no. 2, pp. 303-321

OSTI ID:4126882

Patel, G N; Keller, A

An extensive study has been carried out on the effect of ionizing radiation on polyethylene in the form of solution-grown single crystals to follow up preceding investigations which had indicated that the radiation-induced effects along the fold surfaces could be significantly different from those within the crystal interior. In this first part of the series, radiation-induced crosslinking was investigated in the case of ''crystal core'' material. This material, obtained by removal of the fold surface by oxidative degradation with ozone, consists of isolated foldfree crystal layers of dicarboxylic acids of uniform length, the length itself depending on the fold length of the starting crystal. This ''core material'' was irradiated by $gamma$ rays and the effect of crosslinking was followed by GPC analysis by recording the development of dimer, trimer, etc., peaks in the chromatograms. For a given dose, the fractional amount of crosslinked material is independent of the chain length. This, together with other effects described, provides unambiguous evidence that crosslinking occurs at the chain ends or, in other words, that there is no crosslinking within the interior of the paraffinoid lattice. Further, no permanent scission was observed to occur within the lattice, at least in amounts detectable by the present molecular weight measurements. The obvious significance of these effects for radiation studies on paraffinoid substances in general, beyond those of the present long-chain dicarboxylic acids, is discussed prior to utilizing them in the study of chain-folded polyethylene crystals in the following parts of the series. (auth)

• Research Organization: Bristol Univ., Eng.
• NSA Number: NSA-33-008925
• OSTI ID: 4126882
• Journal Information: J. Polym. Sci., Polym. Phys. Ed., v. 13, no. 2, pp. 303-321, Journal Name: J. Polym. Sci., Polym. Phys. Ed., v. 13, no. 2, pp. 303-321; ISSN JPLPA
• Country of Publication: United States
• Language: English

Related Subjects

*POLYETHYLENES-- CHEMICAL RADIATION EFFECTS
400600* --Chemistry--Radiation Chemistry
CROSS-LINKING
GAMMA RADIATION
MONOCRYSTALS
N40300* --Chemistry--Radiation Chemistry