Journal of Applied Polymer Science, Vol.81, No.1, 91-95, 2001
Dissolution/reprecipitation: A model process for PET bottle recycling
A dissolution/reprecipitation route was followed for the recycling of poly(ethylene terephthalate) (PET). Model experiments an virgin material, either in the form of pellets: or blow-molded bottles, are presented. The process proposed comprises dissolution of the plastic in an appropriate solvent, reprecipitation by using a nonsolvent, thorough washing of the material obtained, and drying. The solvent mixtures involved ar e separated by fractional distillation for further reuse. N-Methyl-2-pyrrolidone (NMP)/n-octane + n-hexane proved to be a particularly effective solvent/nonsolvent system. Further investigation was focused on the effect of the sample history through successive recycling cycles. The recycled material was evaluated in terms of molecular weight, crystallinity, and grain-size analysis, resulting in an excellent quality, competing with the virgin grade.