Also referred to as polyphenylene oxide (PPO), these plastic resins are combined with other polymers to make useful alloys. PPE is compatible with polystyrene and is blended with (usually high-impact) PS over a wide range of ratios. Because both PPE and PS plastics are hydrophobic, the alloys have very low water absorption rates and high dimensional stability. They exhibit excellent dielectric properties over a wide range of frequencies and temperatures. PPE / PS alloys are supplied in flame-retardant, filled and reinforced, and structural foam molding grades. PPE can also be alloyed with nylon plastic to provide increased resistance to organic chemicals and better high-temperature performance. PPE / nylon plastic blends have been used in injection-mold automobile fenders.