the trade name in the USSR for the polyether poly-3,3-bis(chloromethyl)oxetane, whose repeating unit is [—OCH2C(CH2Cl)2CH2—]n. Pentaplast is a thermoplastic linear polymer with a 30-percent degree of crystallization and a molecular weight that ranges from 70,000 to 200,000. A hard, colorless substance, it is self-extinguishing and dissolves only in cyclohexanone and chlorobenzene at elevated temperatures. It resists the action of concentrated mineral acids at 100°C and is destroyed only by the action of strong oxidizing agents, for example, nitric acid and fuming sulfuric acid. Pentaplast is more stable than polyvinyl chloride and less so than fluoroplastics. Its strength indexes are similar to those of polypropylene.
Pentaplast is commercially prepared by the cationic or anionic polymerization of 3,3-bis(chloromethyl)oxetane in blocks or suspensions in organic solvents. It is suitable for injection molding and extrusion and has good adhesive properties. Pentaplast is used as an anticorrosive coating for chemical equipment and pipes, as cable insulation, and to make high-precision parts in mechanical engineering. In the United States, it is manufactured under the trade name Penton.