ISSN:
0959-8103
Keywords:
photoinitiation
;
vanadium chelate
;
styrene photopolymerization
;
free-radical polymerization
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Oxotris(dimethyl dithiocarbamato) vanadium(V) [VO(S2CN(CH3)2)3] sensitizes the polymerization of styrene when irradiated by light of λ = 365 nm at 25°C. Under the experimental conditions employed, no retardation occurs, and the rate of initiation is independent of monomer concentration. The mean values of the quantum yield of iniiation (φi) and polymerization (φo) are 2.85 × 10-3 and 6.72 respectively. Spectroscopic analysis shows that initiation occurs predominatly through scission of the N,N-dimethyl dithiocarbamate ligand ( - SC(S)N(CH3)2) with reduction of vanadium(V) to (IV), and VO (S2CN(CH3)2)2 is the final photolytic product.A reaction mechanism is proposed based on an intramolecular photoredox reaction which leads to the primary formation of SC(S)N(CH3)2 radicals and a vanadium(IV) chelate complex. The rellevant kinetic parameters are evaluated. The polystyrene produced shows a photoactivity when irradiated with UV-light.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pi.1994.210350402
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