PVDF
Polyvinylidene fluoride (PVDF) is a semi-crystalline thermoplastic fluoropolymer. It is readily melt-processible and can be fabricated into parts by injection and compression molding. It combines high mechanical strength with good processability. PVDF is commonly employed in chemical processing equipment such as pumps, valves, pipes, tubes and fittings.
In the recent years, there has been considerable interest expressed in the polymer Polyvinylidene Fluoride (PVDF). The interest it received because it exhibits strongest piezoelectric properties as compared to any other commercial polymer. The polymer is widely used in high tech applications such as chemical process equipment, electrical and electronics, specialty and energy related applications. But, what makes PVDF a high performance plastic in several sectors? Read on to know more.
What is PVDF?
PVDF (PVF2 or Polyvinylidene fluoride or polyvinylidene difluoride) is a semi-crystalline, high purity thermoplastic fluoropolymer. With service temperatures up to 150°C, PVDF displays good combination of properties such as:
- Exceptional chemical resistance
- High mechanical strength
- Piezoelectric and pyroelectric properties
- As well as good processability
Its highly desirable insolubility and electrical properties result from the polarity of alternating CH2 and CF2 groups on the polymer chain.
PVDF is readily melt-processible and can be fabricated into parts by injection and compression molding. As a result, it is commonly employed in chemical processing equipment such as pumps, valves, pipes, tubes and fittings; sensors and actuators etc.
It has many electronic applications, especially as jacketing materials for plenum-rated cable used in voice and video devices and alarm systems. The low flame spread and smoke generation of PVDF is a prime asset in these applications.
PVDF is gaining acceptance as a binder for cathodes and anodes in lithium-ion batteries, and as a battery separator in lithium-ion polymer systems.
Emerging applications of PVDF include fuel cell membranes, and components for aircraft interiors and office automation equipment.
Thanks to its excellent combination of properties and processability, PVDF has become the largest volume of fluoropolymers after PTFE.
PVDF is available commercially in a wide range of melt flow rates and with various additives to enhance processing or end use properties.
How PVDF is produced?
PVDF (homopolymers and copolymers) is generally synthesized by the free radical polymerization of 1,1-difluoroethylene (CH2=CF2). The polymerization takes place in the suspension or emulsion from 10-150°C and pressure of 10-300 atm. The material obtained is then processed into film or sheets.
Thanks to its excellent combination of properties and processability, PVDF has become the largest volume of fluoropolymers after PTFE.
PVDF is available commercially in a wide range of melt flow rates and with various additives to enhance processing or end use properties.
Chlorotrifluoroethylene (CTFE) or hexafluoropropene (HFP) are most commonly employed to prepare PVDF copolymers.
PVDF Copolymers with HFP contain increased flexibility over PVDF homopolymer grades
Copolymers with CTFE are among the most flexible PVDF products with excellent low temperature performance and low shrinkage
