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A model study for the recovery of polymides using the dissolution/reprecipitation technique
Author(s) -
Papaspyrides C. D.,
Kartalis C. N.
Publication year - 2000
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.11225
Subject(s) - caprolactam , dissolution , solvent , materials science , crystallinity , formic acid , polymer , chemical engineering , ketone , distillation , acetone , organic chemistry , polymer chemistry , chemistry , composite material , engineering
A model dissolution/reprecipitation process is studied for the recycling of both polyϵ‐caprolactam (PA 6) and polyhexamethyleneadipamide (PA 6 6). This process comprises dissolution of each of the aforementioned polyamides in an appropriate solvent, reprecipitation by addition of a nonsolvent and finally recovery of the polymers through washing and drying. Dimethylsulfoxide/methyl‐ethyl‐ketone (DMSO/ MEK) proved to be the most suitable solvent/nonsolvent system for the recovery of PA 6, while formic acid/methyl‐ethyl‐ketone was used as a potential pair of solvent/ nonsolvent in the case of recovering PA 6 6. The recycled polyamides were evaluated in terms of the following characteristic properies: molecular weight (based on end‐group analysis and intrinsic viscosity determination), crystallinity and grain size analysis. In all cases, the recycled materials present excellent retention of the properties studied. Finally, the solvent mixtures involved are separated by distillation for reuse.