Polystyrene depolymerization: Scavenging brominated flame retardants - extension

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Polystyrene is a versatile polymer that is produced at enormous scale (millions of tonnes per year) and applied**in many consumer products including packaging. Nonbiodegradable polymers, like polystyrene, represent an**environmental burden; high impact polystyrene (HIPS) is a major component in the electronics industry and**represents a sizable fraction of municipal solid waste. The industry is now attempting to derive value from**waste polymer and end-of life polymer for a feedstock. High impact polystyrene (HIPS) is a copolymer that**contains polybutadiene and acrylonitrile butadiene styrene (ABS) is another copolymer that is the principal**component of computer cases and sewer pipes. End-of-life polystyrene copolymers contain thermal stabilizers,**brominated fire retardants, benzoyl peroxide, antimony trioxide, among other compounds. Brominated**compounds provide fire proof properties to meet UL or CSA fire resistance requirement. However, many of**these compounds are now banned. Lavergne Group is a major Canadian company that recycles polymers and**they have a large supply of HIPS with the brominated compounds that they must remove to meet federal**requirements. Removing these compounds reduces the burden of polystyrene to municipal landfills but will**maintain their supply of feedstock for their customers as they have a viable business operational. Thermal**cracking and pyrolysis are among several technologies to recover valuable styrene (monomer) and**hydrocarbons (benzene, for example). However, we demonstrated that as much of 20 % of the solids remained**after pyrolyis. Furthermore, the cracked products have less value compared to the polystyrene. We will pursue**extracting the brominated compounds by a high temperature (>200 oC) solvent process. The experimental plan**will identify the relationship between bromine extraction efficiency as a function of time, temperature, particle**size, solvent type, and catalyst We will analyse the liquid products by HPLC analyser, GC-MS, FTIR, and**evaluate the solid phase by thermogravimetric analysis. Our objective is to maximize the polystyrene yield**(solids phase) with less than 1000 ppm Br and identify how to recover/treat the soluble compounds.