Polyphenylene Ether or Oxide (PPE/PPO) was commercialized by in 1960. While it was one of the cheapest high temperature resistant plastic but processing was difficult & the impact and heat resistance decreased with time. Mixing it with polystyrene in any ratio could compensate for the disadvantages.
Very Low water absorption, Hot water resistant, Resistant to Alkai & Acid, Very low mould shrinkage, Very low tendency to wrap.