GPPS (General Purpose Polystyrene) is a transparent thermoplastic formed by homopolymerization of styrene monomers, featuring rigid, unbranched molecular chains. It offers excellent transparency, processability, and electrical insulation, with a relatively low density among general-purpose plastics. It is a traditional core material for daily necessities, packaging, electronic accessories, and toys. GPPS density is primarily affected by polymerization process and molecular weight. Virgin material density is extremely stable, with a slight increase after filling or reinforcement. Accurate density is fundamental for lightweight transparent product design and molding.

• Virgin GPPS: 1.04–1.06 g/cm³, typical value 1.05 g/cm³. It offers excellent transparency, high rigidity, and ease of processing with low density, suitable for transparent tableware, toys, packaging containers, electronic enclosures, and lamp shades.

• High-Flow GPPS: 1.05–1.07 g/cm³. Reduced molecular weight improves flowability with slightly higher density, suitable for thin-walled transparent products and precision injection-molded parts.

• Reinforced GPPS: 1.15–1.30 g/cm³. Glass fiber or mineral fillers increase density, improving rigidity and heat resistance for structural transparent components.

• Flame-Retardant GPPS: 1.05–1.08 g/cm³. Flame retardant modification slightly increases density, providing flame-retardant properties for transparent electronic appliance enclosures and switch panels.