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Free radical polymerisation studies of 4‐substituted styrenes , 2. Termination and chain transfer in the polymerisation of styrene, 4‐methoxystyrene and 4‐methylstyrene
Author(s) -
Berry Robert William Huxley,
Ludlow Andrew John,
Mazza Robert John
Publication year - 1997
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1997.021981213
Subject(s) - chemistry , monomer , polymer chemistry , polymerization , dilatometer , chain transfer , styrene , bulk polymerization , radical polymerization , chain termination , radical initiator , polymer , radical , copolymer , organic chemistry , materials science , thermal expansion , metallurgy
The bulk polymerisation of styrene, 4‐methoxystyrene and 4‐methylstyrene was investigated at 60°C using 2,2′‐azoisobutyronitrile (AIBN) as the initiator. Initial rates ( R i 0 ) and efficiencies ( f ) of initiation were calculated from the radioactive content of the polymer obtained by labelling the initiator as either [methyl‐ 14 C 4 ]AIBN or [cyano‐ 14 C 2 ]AIBN. Rates of polymerisation determined gravimetrically are in good agreement with rates determined by the dilatometer technique. An empirical linear relationship between the number of initiator fragments and the degree of monomer conversion was noted. Factors affecting the termination of polymer radicals are discussed and compared with other published work. The polymerisation reaction is terminated predominantly by combination in the case of all three monomers, and chain transfer constants to initiator and to monomer are of the order of 10 −3 and 10 −5 , respectively.