Polyphenylene oxide (PPO) is a thermoplastic engineering plastic formed by the oxidative coupling polymerization of 2,6-dimethylphenol under the action of a catalyst. It can be regarded as the “structural backbone of heat-resistant insulation” - it forms a high glass transition temperature (approximately 210°C) through the steric hindrance effect of the rigid aromatic main chain and the side chain methyl groups. Therefore, it has excellent heat resistance (long-term operating temperature -127°C to 120°C), excellent dimensional stability, outstanding electrical insulation properties, and water resistance, acid and alkali resistance (but poor resistance to organic solvents and oil). PPO is usually blended with polystyrene or high impact polystyrene to form modified polyphenylene oxide (MPPO) to improve processing fluidity. It is widely used in automotive instrument panel frameworks, electronic and electrical enclosure (connectors, coil frameworks), water pump impellers, office equipment housings, and medical devices, where heat resistance, low moisture absorption, and precise dimensions are required.