Noryl is a blend of polyphenylene oxide (PPO) and polystyrene (PS) that was developed by General Electric Plastics in 1966 (now owned by SABIC. It is a rare example of a homogeneous mixture of the two polymers. Most polymers are incompatible with one another, so tend to produce separate phases when mixed. The compatibility of the two polymers in Noryl is caused by the presence of a benzene ring in the repeat units of both chains.