Polystyreenit

Polystyreenit, also spelled polystyrenit, is a synthetic nitro‑substituted polymer derived from the monomer styrene. In its most common form the polymer backbone is identical to that of conventional polystyrene, but each aromatic ring carries one or more nitro (–NO₂) groups that can be introduced either during radical polymerisation of a nitro‑styrenic precursor or by post‑polymerisation nitration of polystyrene. The introduction of nitro groups gives the material a distinct reddish–brown colour and imparting a modest electron‑withdrawing character to the aromatic rings.

The polymer is typically prepared by free‑radical polymerisation of 4‑nitro‑styrene or 2‑nitro‑styrene in bulk or solution conditions. Various initiators, such as azobisisobutyronitrile (AIBN) or benzoyl peroxide, are employed at temperatures between 50 °C and 100 °C. Alternative synthetic routes involve nitro‑alkylation of polystyrene chains and subsequent radical polymerisation. The degree of nitro substitution is controlled by the feed ratio of nitro‑styrene to styrene and can range from 0.5 mol % to 10 mol %.

Polystyreenit is a rigid, brittle solid at room temperature with a glass transition temperature around 100 °C, slightly lower than that of pure polystyrene. It is soluble in aromatic solvents such as toluene and chlorobenzene, but insoluble in aliphatic hydrocarbons. The nitro functionality imparts a modest dielectric constant (~2.6–3.0) and an increased density (≈1.2 g cm⁻³). The material shows moderate resistance to acidic environments but is susceptible to hydrolysis under strongly basic conditions.

Applications of polystyreenit are primarily in the field of electronic materials where its dielectric properties and chemical stability are advantageous. It has been employed as a dielectric layer in capacitors, as a resist in photolithography for microelectronics, and in the manufacture of specialty inks for high‑resolution printing. Owing to its lower toxicity profile compared with fully nitrated aromatic polymers, it is occasionally used as a safer alternative in adhesives and coatings.

Safety data indicate that polystyreenit can irritate eyes and skin and may pose inhalation hazards in dust form. The nitro groups are weakly oxidising and the polymer should be stored away from strong acids or reducing agents. Environmental persistence is moderate; the material degrades slowly under UV radiation and under microbial action in soil, though the nitro groups can release small quantities of NOx gases during high‑temperature incineration. The polymer is therefore handled with standard precautions and disposed of in accordance with local hazardous waste regulations.