Influence of phosphorous‐based flame retardants on the mechanical and thermal properties of recycled PC/ABS copolymer blends

The effects of three commercial aryl phosphate flame retardants (FRs; bisphenol A bis(diphenyl diphosphate) [BDP], triphenyl phosphate (TPP), and a proprietary oligomeric phosphate ester (OPE)) and a compatibilizer (methacrylate‐butadiene‐styrene copolymer [MBS]) on the thermal and mechanical properties of FR‐recycled PC/acrylonitrile‐butadiene‐styrene copolymer (r‐PC/r‐ABS) blends are investigated. The addition of FRs to r‐PC/r‐ABS blends increases the storage, tensile, and flexural moduli, indicating a reinforcing effect. However, at elevated temperatures, FRs reduce the glass transition temperature and act as plasticizers. The thermal stability of r‐PC/r‐ABS/FR blends at 10% mass loss increases in the following order: r‐PC/r‐ABS/TPP < r‐PC/r‐ABS/BDP < r‐PC/r‐ABS/OPE < r‐PC/r‐ABS/OPE/MBS. Kinetics of thermal decomposition of the FR r‐PC/r‐ABS blends is studied calculating the thermal decomposition activation energies by the Flynn–Wall–Ozawa method. Scanning electron microscopy shows that r‐PC/r‐ABS/OPE blend is only partly miscible, while homogeneous structure is formed in the r‐PC/r‐ABS/OPE/MBS blend, which is supported by its good mechanical and thermal properties.