ISSN:
1022-1352
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Only a limited amount of work has been previously published concerning the free radical polymerisation of 4-methoxystyrene and 4-methylstyrene initiated by 2,2′-azoisobutyronitrile (2,2′-azobis(2-methylpropiononitrile)) (AIBN). The present investigation was, therefore, undertaken to establish whether the substituents have a considerable affect on the reaction of 2-cyano-2-propyl radicals at 60°C, relative to styrene. Rates of polymerisation were determined gravimetrically and rates of initiation were calculated from the radioactivity of the polymer, obtained by labelling AIBN with carbon-14. Number average molecular weights (Mn) were determined by gel permeation chromatography (GPC). The order of reaction with respect to initiator concentration was found to be 0.50 for styrene and 0.48 for both 4-methoxystyrene and 4-methylstyrene, which was attributed to their susceptibility to primary radical termination. Polystyryl radicals were also found to undergo primary radical termination and values for the constant {kprt/(ki·kp)} were determined as 1.37 × 104 mol · s · dm-3 for styrene, 1.47 × 104 mol · s · dm-3 for 4-methoxystyrene and 1.30 × 104 mol · s · dm-3 for 4-methylstyrene. The rate of initiation for 4-methoxystyrene is greater than for styrene, which in turn is greater than for 4-methylstyrene.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1997.021980520
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