PPO (Polyphenylene Oxide) is an amorphous high-performance thermoplastic engineering plastic. Its molecular chain has high rigidity, with moderate base density. Core advantages include extremely low water absorption, excellent dimensional stability, outstanding electrical insulation, and hydrolysis resistance, along with balanced heat resistance and mechanical strength, making it a key material for high-precision components in the electronics, electrical, and automotive fields. It should be noted that pure PPO has extremely high melt viscosity and is difficult to process. Most PPO products on the market exist in the form of modified alloys, whose density is mainly affected by the modification formula. Different types and modified versions of PPO have slight density variations, which directly determine the material's processing performance, application scenarios, and cost control range.
General-purpose pure PPO: 1.06–1.08 g/cm³, typical value 1.07 g/cm³. The amorphous structure gives it natural low water absorption and high dimensional stability, with high processing difficulty, mainly used in special precision scenarios with extremely high performance requirements.
PPO/PS (HIPS) modified: 1.05–1.07 g/cm³. By adding polystyrene (PS) or high-impact polystyrene (HIPS) to improve processing fluidity, its density is close to pure PPO, with significantly reduced cost, making it the most commonly used general-purpose injection grade product on the market.
Glass fiber reinforced PPO (10–30%): 1.15–1.32 g/cm³. The higher the glass fiber content, the more obvious the density increase. At the same time, the material's strength, rigidity, and heat distortion temperature are significantly improved, suitable for high-load, high-temperature scenarios.
Mineral-filled PPO: 1.12–1.28 g/cm³. Filling content is positively correlated with density. It mainly adds minerals such as talc and calcium carbonate to focus on improving dimensional stability, reducing warpage, and further controlling production costs.
Flame-retardant PPO: 1.07–1.15 g/cm³. Most adopt halogen-free and phosphorus-based flame-retardant systems. The addition of flame retardants makes the density slightly higher than the base grade, meeting the V-0 flame-retardant requirements of electronic equipment housings and structural components, while retaining excellent electrical insulation performance.
Glass fiber + mineral composite PPO: 1.18–1.35 g/cm³. It combines the high strength of glass fiber with the dimensional stability of minerals, with density between single reinforcement systems, more balanced comprehensive performance, suitable for complex precision structural component design needs.
This density parameter is the core basis for the design of high-precision products such as automotive exterior parts, pump housings, electrical equipment housings, junction boxes, water treatment equipment components, and medical device structural components. The amorphous structure and extremely low water absorption ensure near-perfect dimensional accuracy in humid, high-temperature, and chemically corrosive environments. Density calculation is also key data for product lightweight design, mold cavity design, assembly gap matching, and injection molding process parameter setting, while supporting the play of its core characteristics of high heat resistance, high insulation, and hydrolysis resistance.
