title: Environmentally friendly chemical recycling of poly(bisphenol-A carbonate) through phase transfer-catalysed alkaline hydrolysis under microwave irradiation.
abstract: The various and widespread uses of polycarbonate (PC) polymers require a meaningful and environmentally friendly disposal method. In this study, depolymerisation of polycarbonate with water in a microwave reactor is suggested as a recycling method. Hydrolysis was investigated in an alkaline (NaOH) solution using a phase-transfer catalyst. All of the experiments were carried out in a sealed microwave reactor, in which the reaction pressure, temperature and microwave power were continuously controlled and recorded. In the hydrolysis products, bisphenol-A monomer was obtained and identified by FTIR measurements. PC degradation higher than 80% can be obtained at 160°C after a microwave irradiation time of either 40 min or 10 min using either a 5 or 10% (w/v) NaOH solution, respectively. GPC, TGA and DSC measurements of the PC residues revealed that surface erosion is the degradation mechanism. First-order reaction kinetics were estimated by implementing a simple kinetic model. Finally, greater than 85% degradation was achieved when waste CDs were treated with the same method. The results confirm the importance of the microwave power technique as a promising recycling method for PC-based waste plastics, resulting in monomer recovery in addition to substantial energy savings.
authors.affiliation: Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
authors.forename: Georgia P
authors.initials: GP
authors.lastname: Tsintzou
authors.forename: Eleni V
authors.initials: EV
authors.lastname: Antonakou
authors.forename: Dimitris S
authors.initials: DS
authors.lastname: Achilias
mesh_terms: D001559:Benzhydryl Compounds / Q000737:chemistry* / Q000528:radiation effects*; D002152:Calorimetry, Differential Scanning; D002384:Catalysis; D002850:Chromatography, Gel; D006358:Hot Temperature; D006868:Hydrolysis; D007220:Industrial Waste / Q000032:analysis*; D007700:Kinetics; D008872:Microwaves; D015394:Molecular Structure; D044367:Phase Transition; D011108:Polymers / Q000737:chemistry* / Q000528:radiation effects*; D059027:Recycling / Q000379:methods*; D012972:Sodium Hydroxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water / Q000737:chemistry; D000098826:Bisphenol A Compounds; D000098827:Polycarbonates
chemical_list: D001559:Benzhydryl Compounds; D007220:Industrial Waste; D011108:Polymers; D012972:Sodium Hydroxide; D014867:Water; C028237:bisphenol-A-polycarbonate; D000098826:Bisphenol A Compounds; D000098827:Polycarbonates