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The graft copolymerization of styrene and lignin. I. Hydrochloric acid lignin
Author(s) -
Phillips R. B.,
Brown W.,
Stannett V. T.
Publication year - 1971
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1971.070151203
Subject(s) - lignin , copolymer , styrene , chemistry , polystyrene , polymer chemistry , methanol , polymerization , grafting , hydrochloric acid , solvent , organic chemistry , polymer
The effects of methylation of phenolic hydroxyl groups and addition of solvent on the radiation and chemically initiated graft copolymerization of styrene and hydrochloric acid softwood lignin were studied. In the radiation‐induced experiments, methylation is found to increase the maximum per cent graft obtainable two or threefold, while methanol addition may increase the value tenfold. Chemically initiated experiments indicate that the main effect of methanol addition is to increase the accessibility of the lignin particles. A mechanism of graft copolymerization of polystyrene and lignin is proposed which requires the reaction to proceed primarily by chain transfer of a polystyrene chain radical to lignin and the subsequent reinitiation of polymerization (i.e., initiation of graft copolymerization) by the lignin radical. The grafting of lignin modifications is then dependent on the type of radical formation (i.e., phenoxy or benzylic) most favored, as well as the usual accessibility considerations.