The excellent properties of PVDF screws: good insulation, no rust, corrosion resistance, light weight and beautiful appearance.
What is PVDF?
The full name of PVDF is Polyvinylidene Fluoride, a high-performance fluoropolymer and a key member of the fluoroplastic family. It is widely used in various industrial fields due to its excellent chemical stability, mechanical properties, and special functional characteristics.
I. Core Properties of PVDF
As a fluoropolymer, PVDF has a molecular structure with repeating -CH₂-CF₂- units. The high electronegativity of fluorine atoms and the stable C-F chemical bonds endow it with unique properties:
- Superior Chemical Stability: Resistant to strong acids (e.g., hydrochloric acid, sulfuric acid), strong alkalis (e.g., sodium hydroxide), and organic solvents (e.g., ethanol, acetone). It can only be corroded by a few substances (e.g., concentrated nitric acid, high-temperature strong alkalis), making it suitable for harsh chemical environments.
- Excellent Weather Resistance and Heat Resistance: Has a wide long-term service temperature range (typically -40℃ to 150℃). It can maintain stable performance in environments such as outdoor exposure, high temperature, and high humidity, and is not prone to aging.
- Good Mechanical Strength: Compared with other fluoroplastics (e.g., PTFE), PVDF has higher hardness, better toughness, and excellent impact and fatigue resistance. It can be processed into various forms such as films, sheets, and pipes.
- Special Functional Attributes:
- Piezoelectric/Thermoelectric Properties: After special treatment (e.g., stretching, polarization), it can convert mechanical energy into electrical energy (piezoelectricity) or temperature changes into electrical energy (thermoelectricity), serving as a key material for sensors and energy storage devices.
- Radiation Resistance: Resistant to ionizing radiation such as gamma rays and X-rays, suitable for nuclear industry and medical radiation environments.
- Low Flammability and Low Smoke Emission: Releases little smoke when burned and no toxic gases, meeting high safety standards (e.g., in construction and aerospace fields).
II. Main Application Fields of PVDF
Based on the above properties, PVDF is widely used in industries, electronics, medical care, construction, and other fields. Typical applications include:
| Application Field | Specific Products/Scenarios |
|---|---|
| Chemical & Petroleum | Corrosion-resistant pipes, valves, pump bodies, and storage tanks (for transporting/storing strong acids and alkalis); filter elements (high-temperature and chemical corrosion resistance). |
| Electronics & New Energy | Lithium battery cathode binders (enhancing electrode stability); photovoltaic backsheet films (UV and moisture-heat resistance, protecting battery modules); sensors (using piezoelectric properties for pressure/temperature detection). |
| Construction & Coatings | Exterior wall fluorocarbon coatings (weather-resistant and anti-pollution, used in high-rise buildings and bridges); roof waterproofing membranes (anti-aging, resistant to high and low temperatures). |
| Medical Industry | Medical catheters and syringe components (good biocompatibility, resistant to disinfection and sterilization); radiation shielding materials (radiation resistance). |
| Aerospace | Aircraft cabin interior parts and cable insulation layers (resistant to high and low temperatures, low smoke emission, meeting aviation safety standards). |
III. Comparison with Other Common Fluoroplastics
To better understand the positioning of PVDF, it can be compared with PTFE (Polytetrafluoroethylene, “Teflon”) and FEP (Fluorinated Ethylene Propylene) from the same family:
| Property | PVDF (Polyvinylidene Fluoride) | PTFE (Polytetrafluoroethylene) | FEP (Fluorinated Ethylene Propylene) |
|---|---|---|---|
| Long-term Service Temperature | -40℃ to 150℃ | -200℃ to 260℃ | -200℃ to 200℃ |
| Mechanical Strength | High (hard, tough) | Low (soft, easy to deform) | Medium |
| Processing Difficulty | Low (injection molding, extrusion available) | High (requires special processing) | Medium (extrusion, compression molding available) |
| Special Functions | Piezoelectric/thermoelectric properties | None | None |
| Typical Applications | Lithium batteries, coatings, sensors | Non-stick pan coatings, seals | Cable insulation, laboratory utensils |
In short, PVDF is a fluoropolymer with “balanced performance and special functions”. It not only solves the problem that ordinary plastics are not corrosion-resistant and heat-resistant but also expands its applications in new energy and electronics fields with properties such as piezoelectricity, making it a key material in the industrial sector.