ISSN:
1022-1352
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The utility of two-dimensional wideline separation (2D WISE) NMR in following the phase dependence of the radiation-induced crosslinking of multiphase materials has been demonstrated. Crosslink production in semicrystalline polyolefins by high-energy electron irradiation in air was monitored via the experimentally resolved 1H lineshapes of the respective amorphous and crystalline regions. It was shown that radiation-induced crosslinks can be primarily restricted to one phase or the other by proper functionalization, or nonfunctionalization, of the host polymer. Poly(1,23-tetracosadiyne), a diacetylene-functionalized polyethylene, was synthesized and shown to predominantly undergo crystalline-phase crosslinking for dosages of 100 kGy and less. Thus, chain mobility within amorphous regions may be maintained upon radiation-induced crosslinking. In comparison, linear polyethylene exhibited amorphous-phase crosslinking for electron beam radiation dosages of at least 400 kGy; application of 2D WISE NMR represents a direct method for following this well-known process.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1994.021950502
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