Nature of reactive centres in the cationic polymerization of β-propio- and ϵ-caprolactones under different conditions

Autor:	B.G. Belen'kaya, A.I. Levenko, Ye.B. Lyudvig
Rok vydání:	1978
Předmět:	Kinetic chain length Reaction rate chemistry.chemical_compound Monomer Chain propagation chemistry Bulk polymerization Polymerization General Engineering Cationic polymerization Precipitation polymerization Photochemistry
Zdroj:	Polymer Science U.S.S.R.. 20:632-638
ISSN:	0032-3950
DOI:	10.1016/0032-3950(78)90149-1
Popis:	Complete dissociation of the growing chain ends into free ions has been shown by kinetic and conductometric methods to occur in the polymerization of β-propiolactone at 20°C over (C2H5)2 (HO)SbCl6 as initiator and in the initial stages of that of ϵ-caprolactone at 50°C, using (C2H5)3OSbCl6 or (C2H5)3OSbF6 as initiator. Where the original monomer concentration was small, the ions associated to ionic pairs or triplets and the mechanism of chain propagation changed to one in which the reactive centres were triplets of the type . This was apparent as a reduction in the reaction rate and the electro-conductance of the systems; the order of the reaction with respect to the initiator became larger.
Databáze:	OpenAIRE
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