Poly(p-phenylene oxide) (PPO), poly(p-phenylene ether) (PPE), often referred to simply as polyphenylene oxide, is a high-temperature thermoplastic. It is rarely used in its pure form due to difficulties in processing. It is mainly used as blend with polystyrene, high impact styrene-butadiene copolymer or polyamide. PPO is a registered trademark of SABIC Innovative Plastics IP B.V. under which various polyphenylene ether resins are sold.