P

Polystyrene

IUPAC: poly(styrene)

(C8H8)n Polymers & Plastics CAS 9003-53-6
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Quick Reference
Formula / Notation(C8H8)n
CAS Number9003-53-6
Molecular WeightVariable (polymer)
Melting Point~240 °C (softens ~100 °C)
Boiling PointDecomposes ~300 °C
Density1.04–1.09 g/cm³
SolubilityInsoluble in water
Appearanceclear colourless solid (or white foam)
Also Known AsPS; crystal polystyrene; expanded polystyrene; EPS; styrofoam
CategoryPolymers & Plastics

What is Polystyrene?

Polystyrene (PS) is a synthetic aromatic hydrocarbon polymer made from styrene monomers (–CH₂–CH(C₆H₅)–)n. It is one of the most widely used plastics globally and can be manufactured as a rigid solid or as a foam (expanded polystyrene, EPS). Its glass transition temperature is approximately 100 °C, above which it becomes soft and moldable. Polystyrene is transparent in its standard form and is easily coloured or modified with additives.

Formula & Notation

(C8H8)n

IUPAC Name: poly(styrene)

Other Names / Synonyms: PS; crystal polystyrene; expanded polystyrene; EPS; styrofoam

Properties & Characteristics

Appearance: clear, colourless solid; can be white foam (EPS). Molecular formula: (C8H8)n. Glass transition temperature (Tg): ~100 °C. Density: 1.04–1.09 g/cm³ (solid), 0.011–0.032 g/cm³ (EPS foam). Solubility: insoluble in water; soluble in aromatic solvents (toluene, xylene), ketones, and esters.

Physical Data

PropertyValue
Melting Point~240 °C (softens ~100 °C)
Boiling PointDecomposes ~300 °C
Density1.04–1.09 g/cm³
Molecular WeightVariable (polymer)
SolubilityInsoluble in water
Appearanceclear colourless solid (or white foam)

Uses & Applications

Disposable food packaging, cups, and containers. Insulation foam (EPS/XPS). Laboratory Petri dishes and cell culture plates. Model making and crafts. CD/DVD cases. Electrical insulation components.

Safety Information

Considered low acute toxicity in solid form. Releases toxic styrene monomer and other compounds when burned. EPS foam is an environmental concern — difficult to recycle. Styrene is a potential carcinogen. Consult SDS before processing.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Polystyrene
Formula (C8H8)n
CAS Number 9003-53-6
Molecular Weight Variable (polymer)
Synonyms PS; crystal polystyrene; expanded polystyrene; EPS; styrofoam

Frequently Asked Questions

Polystyrene (PS) is a synthetic aromatic hydrocarbon polymer made from styrene monomers (–CH₂–CH(C₆H₅)–)n. It is one of the most widely used plastics globally and can be manufactured as a rigid solid or as a foam (expanded polystyrene, EPS). Its glass transition temperature is approximately 100 °C, above which it becomes soft and moldable. Polystyrene is transparent in its standard form and is easily coloured or modified with additives.

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.