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Initiation and Propagation Steps in the Solid State Polymerization of Vinyl Monomers
Author(s) -
Chapiro Adulphe
Publication year - 1972
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.197200020
Subject(s) - chemistry , monomer , polymerization , crystallite , chain propagation , polymer , eutectic system , solid state , crystal (programming language) , double bond , polymer chemistry , lattice (music) , crystal structure , chemical physics , crystallography , organic chemistry , microstructure , physics , computer science , acoustics , programming language
Several problems raised by initiation and propagation steps in solid‐state polymerizations are reviewed on the basis of data taken from the literature as well as from unpublished work. The nature of the initial active centers is briefly considered; their addition to double bonds within the crystal is discussed. Examination of initiation yields in radiation‐induced polymerizations shows that the efficiency of chain initiation rises with temperature. In most vinyl monomers, the propagation process, which is severely hindered in the crystal, presumably starts at lattice imperfections and thereafter proceeds on behalf of the additional imperfections introduced by the accumulated polymer. In a few specific cases the orientation of the double bonds in the crystal or their localization in certain regions of the crystal favours chain propagation and may result in a stereocontrolled reaction. The role of crystallite boundaries is emphasized particularly in the case of copolymerizations which take place in eutectic mixtures of two monomers.