1. CORPORATE TRAINING AND PLANNING SPECIALTY PLASTICS Polyvinylidenefluoride (PVDF)

2. CORPORATE TRAINING AND PLANNING Polyvinylidenefluoride (PVDF)

3. CORPORATE TRAINING AND PLANNING General Description Introduced by Pennwalt Corp. in 1961, PVF 2 or PVDF is a high molecular weight homopolymer. The monomer an be obtained from trichloroethylene by reacting with hydrofluoric acid and the action of metallic zinc on the difluorodichloroethane formed. The partially crystalline polymer contains over 57% w/w fluorine.

4. CORPORATE TRAINING AND PLANNING Particular advantages of PVDF are: - high mechanical strength, stiffness and toughness, -relatively resistant to high and low temperatures -- tough even at low temperatures, - good chemical resistance.

5. CORPORATE TRAINING AND PLANNING Structure and Properties The degree of crystallinity depends on the history of the molding. Rapid cooling of thin­ walled moldings and film results in transparent products; slow cooling or annealing at 135 °C lead to highly crystalline products with high stiffness and compressive creep strength.

6. CORPORATE TRAINING AND PLANNING Availability PVDF is supplied in various grades as: - granules for injection molding and extrusion, - as powder and - as 45 to 50% dispersions in organic solvents (dimethyl phthalate & diisobutylketone).

7. CORPORATE TRAINING AND PLANNING Mechanical Properties Transition Temperatures - PVDF has a glass transition temperature Tg of 40 °C, a crystallization temperature of 140 °C and a melting point of 171 °C.

8. CORPORATE TRAINING AND PLANNING Thermal Properties PVDF can be used over the range -60 to +150°C. It withstands temperatures as follows without any noticeable degradation: - 150°C over 1 year, - 260°C up to 12 hours, - 240 °C up to 30 minutes, - at 480 °C it decomposes within a few minutes. Copper, aluminium and iron catalyze decomposition.

9. CORPORATE TRAINING AND PLANNING Electrical Properties Like PVF, PVC and PVDC, the polar nature of PVDF precludes its use for high frequency applications. The volume resistivity is greater than 10 15  at 30 °C making it highly suitable for use in the mains frequency range. The dielectric strength (1 mm film) is 22 kV/mm, the surface resistance exceeds 10 13 

10. CORPORATE TRAINING AND PLANNING Chemical Properties Resistance to Chemicals PVDF is resistant to acids (apart from fuming nitric acid), alkaline solutions, solvents, aromatic, aliphatic or chlorinated hydrocarbons, oils, fats, fluoro-refrigerants. It is not resistant to primary amines at elevated temperatures, hot acetone (thin films), strongly polar organic compounds such as dimethylformamide, diethyl acetamide, cyclohexanone, ketones, esters.

11. CORPORATE TRAINING AND PLANNING Weathering Resistance PVDF deteriorates slightly outdoors. Resistance to Radiation PVDF is resistant to UV; there is slight degradation in the range 200 to 400 nm. Its resistance to high energy radiation is superior to that of other fluoroplastics.

12. CORPORATE TRAINING AND PLANNING Flammability PVDF is classified as V-0 to UL94. The oxygen index is 44%. Toxicological Assessment There are no restrictions on the use of PVDF with foodstuffs. It is non-toxic. Gases liberated during processes must be ventilated.

13. CORPORATE TRAINING AND PLANNING Processing - 1 Injection molding, extrusion and coating are the most important methods of processing PVDF. The storing temperature of coatings produced by spraying, dipping or casting is 190 to 215°C.

14. CORPORATE TRAINING AND PLANNING Processing-2 It is absolutely essential that the surfaces of plasticizing screws in injection molders or extruders do not contain any boron. Boron-containing products such as various glass fiber materials or MoS 2 are incompatible with PVDF and cause spontaneous decomposition of the product during processing (fire, vaporization). This can also occur with colorants, fillers and reinforcements not certified by the manufacturer. Suitable pigment concentrates are available.

15. CORPORATE TRAINING AND PLANNING Joining -1 Welding Welding with round nozzle345 + 10°C Welding with high speed nozzle350 + 10°C Heated tool welding230 °C Melt pressure0.5 bar Welding pressure2 bar HF welding is suitable for wall thicknesses up to 2 mm Ultrasonic welding: near and remote field methods.

16. CORPORATE TRAINING AND PLANNING Joining-2 Bonding PVDF with PVDF: solvent adhesives as for PVC-U PVDF with PVDF or other materials: two- pack adhesives based on Epoxide resin. Surfaces to be bonded must be roughened.

17. CORPORATE TRAINING AND PLANNING Typical Applications Seals, pump and valve components, membranes, transparent rigid pipes (for HF and HC!), fittings, linings for pipes, vessels and autoclaves. films for packaging pharmaceuticals, medical instruments, shrink tubing, corrosion- and weather-resistant laminates for wood and metal, cable sheathing, monofilaments for manufacturing filter cloth and piezo and pyroelectrical films for hydrophones, infrared detectors, respiration monitors, muscle sensors and security equipment. Modification of the relatively stiff homopolymer has resulted in more flexible grades thus opening up new applications. The melting range of the modified material is 162 to l65°C.

18. CORPORATE TRAINING AND PLANNING Typical Applications-1 Seals, pump and valve components, membranes, transparent rigid pipes (for HF and HC!), fittings, linings for pipes, vessels and autoclaves. films for packaging pharmaceuticals, medical instruments, shrink tubing, corrosion- and weather-resistant laminates for wood and metal, cable sheathing, monofilaments for manufacturing filter cloth.

19. CORPORATE TRAINING AND PLANNING Applications-2 Piezo and pyroelectric films for hydrophones, infrared detectors, respiration monitors, muscle sensors and security equipment. Modification of the relatively stiff homopolymer has resulted in more flexible grades thus opening up new applications. The melting range of the modified material is 162 to l65°C.

20. CORPORATE TRAINING AND PLANNING Trade Names Kynar (Arkema Inc.) Dycon (Dyncon, US) Kureha (Kureha Chern. Ind., IP) Solef (Solvay Solexis, US) Hylar (Solvay Solexis, US) Dykor (Whitford Corp. US)

21. CORPORATE TRAINING AND PLANNING Further Reading 1.BRYDSON, J.A, Plastics Material, Butterworth Heinemann, oxford, New Delhi (2005) 2.DOMININGHAUS.H, Plastics for Engineering, Hanser publishers, Munich, New York (1998) 3.CHARLESS A. HARPER, Modern Plastics Hand Book McGraw – Hill, New York (1999)

22. CORPORATE TRAINING AND PLANNING Table 1Guide values of properties of Fluorine containing polymers PropertiesUnitsPTFEFEPPCTFEPVF PVDF Densityg/cm 3 2.15-2.202.12-2.172.10-2.121.38-1.571.7 Water absorption (23°C, 24h)%0.04 Mechanical Tensile strengthN/mm 2 25-3622-2832-4049-12746 Elongation at break%350-550250-330128-175115-250100-400 Tensile modulus of elasticityN/mm 2 408350 1050-2110 1800840 Thermal Melting Point°C327290216198171 Service temperaturein air without mechanical loading short-termC300250180 long-termC250205150 100-120 Glass transition temperature°C12745-2040 Heat deflection temperature°C12170126 Coefficient of linear expansion between 0- 50°C K -1.10. -6 10080602085 Specific heat capacitykJ/kg K1.01.20.9

23. CORPORATE TRAINING AND PLANNING Table 1Guide values of properties of Fluorine containing polymers PropertiesUnitsPTFEFEPPCTFEPVF PVDF Electrical Volume resistivity  cm >10 18 >2x10 18 >1.20x10 18 3x10 13 2x10 14 Surface resistance  10 17 10 16 Dielectric constant<2.12.12.3-2.78.57.72 Dissipation factor, tan  (10 3 Hz) 0.0002 0.023-0.027 0.0150.018 Dielectric strengthkV/mm600-800800450-550 Flammability (ASTM D65)Non-flammable Clarityopaque Transparent - transluscent