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The polycondensation of lithium 11–bromoundecanoate in aqueous media
Author(s) -
Shigetomi Yasumasa,
Kojima Takehiro
Publication year - 2003
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.12129
Subject(s) - ethylene glycol , aqueous solution , polymer chemistry , condensation polymer , polymer , condensation reaction , solvent , carboxylate , chemistry , polymerization , lithium (medication) , bromine , melting point , materials science , organic chemistry , catalysis , medicine , endocrinology
To obtain a biodegradable plastic, polycondensation, the substitution of bromine by carboxylate was carried out on lithium 11–bromoundecanoate. Using water as a solvent, the formation of a double bond was detected between 70 and 100°C, yielding a good quantity of polymer. Water is recommended as the best solvent for the reaction. Thermodynamic investigations were carried out by using ethylene glycol and water. The reaction is believed to proceed according to the S N 2 mechanism. The Δ H and Δ G values for condensation in ethylene glycol were slightly higher than for those in water, but the reaction rate in water at 70°C was 7 times greater than that in ethylene glycol. The enhancement of dissociation accounts for the advantageous condensation in aqueous media. Furthermore, Δ S shows negative values and Δ G shows positive values, meaning that the reaction should proceed exothermically and not spontaneously. Experiments to condense 11–bromoundecanoate in aqueous media were carried out for ten days in a water bath, kept at 70°C, using 25 mL of 0.05 M 11–bromoundecanoate. The degree of polymerization for the resulting polymer was found to be 23 by the end group assay for both bromine and carboxylate. Neither a melting point nor glass transition point for the product were observed. The polymer formed decomposes at 300°C and instantly disperses. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 130–134, 2003