Evaluation of accelerated solvent extraction (ASE) followed by postcondensation step (SSP) to extract contaminants from PET flakes

• Published in: Progress in rubber, plastics and recycling technology Vol. 32; no. 2; pp. 73 - 86
• Main Authors: Santos, A S F, Baraldi, P T, Medeiros, E S, Agnelli, J A M, Correa, A G, Sati, Manrich
• Format: Journal Article
• Language: English
• Published: 01.01.2016
• Subjects: Acetone; Contaminants; Decontamination; Food packaging; Mathematical models; Polymerization; Solvent extraction; Solvents
• ISSN: 1477-7606
• DOI: 10.1177/147776061603200202

Aiming to reduce the overall energy consumption of PET super-clean technologies, without using hazardous and large amounts of solvents, this work deals with accelerated solvent extraction followed by solid state polymerisation (ASE-SSP) as an alternative way to decontaminate recycled PET for direct food contact applications. The main effects of the extraction ASE parameters (temperature, flow rate and pressure) in extraction efficiency of toluene and benzophenone, used as model contaminants, from PET were evaluated using a first-order fractional experimental design. Subsequently, PET chips were submitted to a SSP process to remove residual acetone, used as the extractor solvent, from PET. Extraction yield was quantified by gas chromatography with flame ionisation detector (GC-FID). Results showed that the only parameter that affects negatively the decontamination process was an increase in temperature. Moreover, the SSP process helped to remove residual acetone from PET reaching decontamination levels as high as the FDA recommendations for direct food contact packaging. 52 Refs.