Alkaline hydrothermal treatment of brominated high impact polystyrene (HIPS-Br) for bromine and bromine-free plastic recovery.
A method to recover both Br and Br-free plastic from brominated flame retardant high impact polystyrene (HIPS-Br) was proposed. HIPS-Br containing 15% Br was treated in autoclave at 280 degrees C using water or KOH solution of various amounts and concentrations. Hydrothermal treatment (30 ml water) leads to 90% debromination of 1g HIPS-Br but plastic is strongly degraded and could not be recovered. Alkaline hydrothermal treatment (45 ml or 60 ml KOH 1M) showed similar debromination for up to 12 g HIPS-Br and plastic was recovered as pellets with molecular weight distribution close to that of the initial material. Debromination occurs at melt plastic/KOH solution interface when liquid/vapour equilibrium is attained inside autoclave (280 degrees C and 7 MPa in our experimental conditions) and depends on the plastic amount/KOH volume ratio. The antimony oxide synergist from HIPS-Br remains in recovered plastic during treatment. A pictorial imagination of the proposed debromination process is presented.
Brebu
Mihai
M
Department of Applied Chemistry, Faculty of Engineering, Okayama University, 3-1-1 Tsushima Naka, Okayama 700-8530, Japan.
Bhaskar
Thallada
T
Muto
Akinori
A
Sakata
Yusaku
Y
D000468:Alkalies / Q000737:chemistry*; D001966:Bromine / Q000737:chemistry*; D010969:Plastics / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared
D000468:Alkalies; D010969:Plastics; D011137:Polystyrenes; D001966:Bromine