polyvinyylidenefluoridi

Polyvinylidene fluoride, abbreviated PVDF, is a high-performance fluoropolymer used for its chemical resistance, mechanical strength, and thermal stability. Its repeating unit is -CH2-CF2-, derived from the monomer vinylidene fluoride. PVDF occurs in several crystalline forms (alpha, beta, gamma); processing conditions can influence the relative amounts of each form. The beta phase is polar and can exhibit piezoelectric properties when oriented, which enables certain sensing and actuation applications.

Key properties of PVDF include excellent resistance to solvents, acids, and bases, as well as good weatherability and weathering resistance. It has a high melting point around 177°C and a typical continuous operating temperature near 150°C, with processing temperatures often reaching up to 250°C. PVDF is an electrical insulator with high dielectric strength and good mechanical toughness. It is available as a homopolymer and as copolymers, notably PVDF-HFP (vinylidene fluoride copolymerized with hexafluoropropylene), which offers greater flexibility and lower crystallinity.

Applications of PVDF span many industries. It is used in chemical processing equipment, linings, pipes, and geomembranes due to its chemical inertness. PVDF is common in membranes for water treatment, coatings for corrosion protection, and as a binder or coating in electrical cable insulation. The material is also employed in sensors, actuators, and energy-harvesting devices leveraging its piezoelectric properties, as well as in lithium-ion battery separators and other battery components. Medical device coatings and high-purity applications benefit from PVDF’s purity and chemical resistance.

Production of PVDF typically involves radical polymerization of vinylidene fluoride in aqueous media (emulsion or suspension), yielding either the homopolymer or copolymers with fluorinated comonomers. Environmental and safety considerations focus on managing fluorinated effluents and ensuring proper disposal or recycling of fluoropolymers.