ISSN:
0025-116X
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
Recently there has been a growth of interest in the use of diaryliodonium salts (Ar2I+X-), triarylsulfonium salts (Ar3S+X-) and triarylselenonium salts (Ar3Se+X-) as photochemical initiator for cationic polymerizations. It is suggested by Ledwith that electron transfer to these cations results in fragmentation with the formation of aryl radicals and if the reducing species is a suitable free radical, a chain reaction for formation of cation will occur.We carried out radiation-induced polymerization of α-methyl-styrene in dichloromethane and bulk cyclohexene oxide in the presence of triphenyliodonium salt (C6H5)2 (I+PF-). Polymerization of these monomers was observed in the presence of these salts (G(-M)⋍ 1300), while no polymer was obtained in the absence of salts. Postpolymerization was negligibly small. This polymerization is considered to be initiated by the reaction of free radicals produced by radiation with cation salts and to proceed by cationic mechanism, since α-methylstyrene polymerized by ionic mechanism but hardly polymerizes by radical mechanism and this polymerization was suppressed in the presence of a small amount of water. The initiation mechanism of this polymerization was investigated by the use of pulse radiolysis technique.
Zusätzliches Material:
9 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/macp.1985.020131985114
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