ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The activated anionic polymerization of ∊-caprolactam is strongly affected by LiCl addition to the polymerizing medium. Large variations in the yield of the polymerization products are induced by increasing salt content: both high polymer and cyclic dimer yields sharply decrease as functions of the salt concentration, whereas monomer and (in part) higher oligomers show a relevant increase. Also the production of low molecular weight side products is influenced by LiCl: higher salt concentrations induce the formation of larger amounts of side compounds. Monomer equilibrium data reveal that the salt negatively affects the thermodynamics of polymerization. ΔG0p variation as a function of LiCl content shows an increasingly relevant influence of the entropic contribution to the standard free energy change. The effects of LiCl on ring-ring equilibria are qualitatively interpreted on the basis of both the strong ion-ion interactions between Li+ ions and carbonyl groups and the interchain densification process.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1982.021830910
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