Polyvinylidene fluoride
PVDF
Thermoplastic
Fixed
1.76 to 1.78 g · cm -3
175 ° C.
Partially crystalline
2100 ( train )
0.03-0.04 %
0.2 W / ( m · K)
14 · 10-5 K-1
Polyvinylidene fluoride ( PVDF abbreviation ) is an opaque, semi-crystalline, thermoplastic fluoropolymer.
Production
The base materials for PVDF are hydrogen fluoride and methyl chloroform, which are converted to chlorodifluoroethane and further vinylidene fluoride. Vinylidene fluoride is then polymerized in ultrapure water under controlled pressure and temperature conditions by means of a catalyst, polyvinylidene fluoride.
Manufacturers and trade names
- Arkema - Kynar ® PVDF
- Dyneon - Dyneon ® PVDF
- Solvay - Solef ® PVDF
- Georg Fischer AG - SYGEF ® PVDF
History
PVDF was in 1961 under the brand name " Kynar " of Pennwalt Corp.. placed on the market. 1969, the piezoelectric effect of PVDF was discovered by Kawai. Nakamura and Wada Two years later also observed ferroelectric properties in PVDF.
Use
Because of its good thermal and chemical resistance of PVDF is used as a lining for pipes or external components. It is also used for gaskets, membranes, and packaging films. It also finds application in metrology, such as the coating of probes. Since the material according to the corresponding polarization as compared to other polymers is strong piezoelectric effects, it is used in such as microphones, hydrophones, actuators and speakers. Moreover, it is to be tested for variable mirror in space technology. In microelectronics, the ferroelectric properties of PVDF can be used in the future for computer memory.
In the life sciences PVDF membrane is used as support for the Western blot. Compared to nitrocellulose PVDF membranes are more expensive, but they are also more stable and allow multiple use ( reprobing ). Another application is medical technology where PVDF can be used as denture base material.
Since it can be produced highly pure, it is for example in chip production ( Microelectronics ) used for piping systems for the transport of high purity media such as ultrapure water.
In the PVDF membrane technology is widely used ( for example, bacteria filters, which are required for sterile filtering solutions in biochemistry ). It makes use of use of chemical resistance, allowing the material, more intense dry cleaners to get through than some other membrane materials. However, during the filtration, the hydrophobic properties of PVDF disadvantageous.