Recovery of poly(methyl methacrylate) by the dissolution/reprecipitation process: A model study
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Poulakis, JG
(EN)
Gouli, S
(EN)
Papaspyrides, CD
(EN)
Approaches to plastics recycling mainly include direct recovery keeping the polymer structure intact, depolymerization and then reuse of monomers, and methods involving reduction of polymer to gases and low molecular weight oils. The model process presented here belongs to the first category: It is proposed dissolution of the starting material, reprecipitation, thorough washing of the polymer obtained, and drying. With regard to the solvent mixtures involved, these are separated by distillation for further reuse. The technique is applied to poly(methyl methacrylate) (PMMA) molding compound, recycled as model starting material. The following criteria are considered: (a) precipitation of the polymer in an acceptable form; (b) maximum ''waste'' concentration; (c) maximum solution/nonsolvent volume ratio; and (d) maximum extent of poly(methyl methacrylate), solvent, and nonsolvent recovery. On the basis of these criteria, toluene/n-hexane proved to be the most satisfactory solvent/nonsolvent system. (C) 1994 John Wiley & Sons, Inc.
(EN)
