ПОЛИ (ВИНИЛФТОРИД)

Химические свойства

The polymerization of vinyl fluoride has been reported to be difficult but the polymer is available in film form. Details of the polymerization techniques used have not been disclosed. The polymer may be obtained by polymerization of vinyl fluoride in the presence of water, using benzoyl peroxide as initiator at 80°C and pressures up to 100 MPa (1000 atmospheres).
Poly(vinyl fluoride) (PVF) resembles poly(vinyl chloride) in chemical properties but its mechanical properties are generally superior because of its much greater ability to crystallize. The fluorine atom is sufficiently small to permit the molecules to pack in the planar zig-zag fashion of polyethylene. Thus films of poly(vinyl fluoride) have high tensile and impact strengths and outstanding resistance to flexural fatigue. The polymer is insoluble below about 100°C but dissolves above this temperature in certain highly polar solvents such as dimethylformamide. The polymer is also highly resistant to hydrolysis.
Although poly(vinyl fluoride) is more heat resistant than poly(vinyl chloride), it has a tendency to eliminate hydrogen fluoride and instability at processing temperatures makes handling difficult. The weather resistance of poly(vinyl fluoride) is exceptionally good and the film is used particularly for outdoor applications such as glazing in solar energy collectors.

Определение

ChEBI: A polymer composed of repeating fluoroethyl units.

прикладной

The linear macromolecule of polyvinyl fluoride (PVF) is based on the monomer unit: [—CH2 —CHF—]n. PVF which is only used industrially as a thin film, exhibits good resistance to abrasion and resists staining. It also has outstanding weathering resistance and maintains useful properties from –100 to 150°C.

Промышленное использование

Polyvinyl fluoride is a tough, partially crystallinethermoplastic material that has a highersoftening temperature than polyvinyl chloride.Films and sheets are characterized by highresistance to weathering.
Films are used in industrial and architecturalapplications. Coatings, for example, onpipe, are resistant to highly corrosive media.