Thermal degradation of poly(methyl methacrylate) polymers: Kinetics and recovery of monomers using a fluidized bed reactor

Poly(methyl methacrylate) (PMMA) is a versatile transparent thermoplastic that is used in a wide range of fields and applications, such as in the lenses of exterior lights of automobiles, in electronics, in food containers and in artificial marble. When PMMA is subject to thermal degradation conditions, it degrades mainly into its monomer, methyl methacrylate (MMA). In this study, a virgin PMMA copolymer composed of 97.5% methyl methacrylate, 2.5% methyl acrylate (MA) and PMMA waste plastics were investigated. Kinetic measurements of the thermal degradation of the virgin copolymer were carried out with a TGA. The Chatterjee–Conrad (CC) and Freeman–Caroll (FC) models were applied to determine the pyrolysis kinetic parameters. Both models simulated the experimental DTG curves fairly well. In addition, pyrolysis of the virgin copolymer and the PMMA wastes was carried out using a fluidized bed reactor to recover the monomer. The reaction temperatures ranged from 450 to 500 °C. In each case, the rate of oil recovery was over 97%, and the content of the MMA in the oils was up to 98 wt%. The MMA recovered from the experiments can be used as feedstock for the polymerization of PMMA.