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What Is PVDF Material And Its Industrial Importance

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What exactly is PVDF?

Polyvinylidene fluoride, or PVDF, is a semi-crystalline structured thermoplastic fluoropolymer that is highly inert, tough, and stable. Its melting point is 175°C and can withstand service temperatures of up to 150°C. PVDF material has excellent chemical resistance, high crystallinity, and good thermal stability, to name a few of its many advantages.

Click here to know more technical details about PVDF Material.

pvdf sheets

How is PVDF manufactured?

PVDF Sheet and resin are created by polymerising 1,1-difluoroethylene (CH2=CF2) using free radicals. The polymerisation occurs in an emulsion at 10-150°C and 10-300 atm pressure. The material obtained is then formed into films, rods, tubes, and sheets.
PVDF polymer is most commonly produced using chlorotrifluoroethylene (CTFE) or hexafluoropropene (HFP).
PVDF copolymer made from HFP is more flexible than PVDF homopolymer grades.
CTFE-derived comoolymes outperform HFP-derived polymers. They are more flexible, shrink less, and have an excellent low-temperature performance range.
Furthermore, using crosslinking, Polyvinylidene Fluoride is exposed to ionising radiation, allowing for various modifications to its thermal and mechanical properties. Furthermore, different resins, such as acrylics, methacrylic, and acrylic rubbers, are partially compatible with the polymer.

PVDF material properties:

Properties	Values	Units
Processing Temprature	-220°C	–
Tensile Strength @23°C	50	Mpa – ASTM – D638
Thermal Conductivity@23°C	0.2	W/m.k – ASTM C177
Impact Strength	No Break	–
Melting Point	338-347	deg F
Dielectric Strength	20-25@ 1mm thick	kV.mm – ASTM D149
Elongation at Break @23°C	0.4	ASTM-D1894
Weathering resistance	Excellent	–
Continues working temperature	150	°C
Limiting Oxygen Index	44	%
Coefficient of friction	0.4	ASTM-D1894

PVDF Crystal Structure:

As previously stated, it is a semi-crystalline polymer that is 50% amorphous. The structure is designed so that most of the VDF units are linked from head to tail, with only a small number of units linked head to head.

The fluoropolymer exists in four different conformations: α, β, γ, and δ and shape.

Because the C-F bonds are oblique, an alignment is formed to achieve the greatest dipole movement in the same direction. Concerning the phase, it is the prudent phase due to the resin’s piezoelectric properties.

The dipole movement in the opposite direction to crystallites results in zero net polarisation.

Mechanical Properties:

Although PVDF has a high tensile modulus, it has a low impact strength. HFP and CTFE rearrangements can help improve flexibility and impact strength while decreasing tensile modulus.

PVDF is noncombustible and will not drip. It is self-extinguishing and has good UV light resistance.

You can also use a PVDF ball valve for various reasons.

Physical Properties:

Among commercial fluoropolymers, the polymer has one of the highest heat deflection temperatures under load (148°C @0.5Mpa) and the lowest melting point (178°C).

PVDF polymers have lower imbuing values than other PVDF plastic due to their high crystallinity and surface tension. The same imbuing effects can be seen in gases and liquids. However, the ability to imbue depends entirely on the crystalline modification of parts.

Chemical Resistance:

All fluoropolymers (including PVDF) have differing chemical resistance to various chemicals. At high temperatures, the polymer is blended with organic solvents such as animes and esters, allowing it to be used as corrosion resistance glazing on chemical processing equipment.

PVDF has some resistance to organic acids, aliphatic and aromatic hydrocarbons, alcohols, and halogenated solvents. It is, however, easily attacked by strong bases and ketones.

Electrical Properties:

PVDF material has a high dielectric strength and dissolution factor. However, it has poor electrical properties, which allows the polymer to be easily used in films with piezoelectric behaviour.

These films are formed in the B-phase conformation. The surfaces of both films will be glittered and subjected to high voltage, leaving them permanently polarised.

PVDF Processing:

PVDF is available in various grades and forms, including powders and pallets. It is easily processed using traditional injection moulding, extrusion, compression, and transfer moulding methods. You can do this from the best PVDF fittings manufacturers like Petron Thermoplast.

Drying isn’t necessary in most cases, but some may require it. The processing temperature is kept constant at 190 to 280°C.

Injection Molding	Extrusion
Melt Temprature – 200°C to 270°C	Attention must be given to removing dead spots, or it can lead to the creation of degradation.
Advisable mold temprature is 50°C to 90°C	Reemmded extrduion temprature – 230°C to 290°C
PVDF’s higher melt viscosity becomes an important factor to keep the mold design accurate	extrusion of PVDF doesn’t require additional aids, lubricants, and heat stabilizers
Shrinkage – 3 to 4%	Rececemneod L/D ration – 20
Applications – Valves, filter plates, pipelines, coil bodies, fittings, etc.	Applications – Pipes, tubes, heat shrinkable tubings, etc.

Applications of PVDF:

It is used in various electrical and electronics industry applications, including aircraft wires and cables, high-temperature wiring, home appliances, and industrial power control systems.
With the help of some additives, good corrosion properties can improve its applicability to heavy industries such as oil and gas, automotive, marine, and petrochemicals for gaskets, seals, linings, etc.
It is now widely used in filtration equipment such as housings, filters, membranes, etc.
Because of its high thermal and chemical stability, polyvinylidene fluoride is also used to make separators in lithium-ion batteries. These membranes are in high demand because the market for electric vehicles is expected to grow significantly.
Through coating and layering applications, it is also used to improve metals’ chemical resistance and weatherability, such as aluminium and galvanised steel.
PVDF Sheet is used to manufacture flexible tubing and liners for use in water systems, chemical pipes, automobile fuel lines, and storage.
Piezoelectric films are excellent transducers. Because they are malleable, rigid, and lightweight, they can be shaped into various geometries, resulting in one-of-a-kind and innovative applications.

The Future of PVDF:

According to a study, the global Polyvinylidene Fluoride market was valued at USD 535.4 million in 2019 and is expected to reach USD 1567.5 million by the end of 2026, representing a 16.4 per cent CAGR.
Sure, the numbers have changed dramatically due to the Covid-19 pandemic, and predicting the short-term growth outlook for PVDF is difficult. On the bright side, as I write this, a vaccine has been developed, people have begun to emerge and go to work, and the world is gradually opening up.
The Asia-Pacific region is the world’s largest producer of Polyvinylidene Fluoride and will continue to be so for the foreseeable future.

FAQs:

What’s the distinction between PVC and PVDF?

The main difference between PVDF and PVC is the working temperature – PVDF works best at 284°F, and PVC works best at 140°F. PVFD is also more mechanically durable than PVC and more resistant to a wider range of chemicals and permeation.

Is PVDF acid proof?

PVDF fittings have outstanding chemical and cd resistance properties. It is particularly resistant to organic and inorganic acids, halogenated solvents, and hydrocarbons. It can withstand a wide range of corrosive fluids and solvents.

Is PVDF a piezoelectric material?

When PVDF is poled, it transforms into an efficient ferroelectric polymer with excellent piezoelectric and pyroelectric properties. These characteristics make PVDF an excellent choice for sensor and battery applications.

What’s the distinction between PVDF and PTFE?

The primary distinction between PVDF and PTFE membranes is that PTFE membranes can be used in aggressive filtration solutions and strong acids. On the other hand, PVDF membranes perform admirably in the filtration of non-aggressive aqueous and mild organic solutions.

What is the distinction between PVDF and metal powder coating?

PVDF metal coating is a liquid coating system based on resin. Powder coating, on the other hand, is an electrostatic process in which an electrostatically charged powder is sprayed onto a metal surface. Both coatings are effective, but PVDF coating outlasts powder coating.

Endnote:

PVDF has numerous industrial and domestic applications. As a result, it should be of high quality. PVDF resin and plastic is a versatile and useful fluoropolymers. Petron Thermoplast sells PVDF pipe and other PVDF material products at a reasonable price.[/vc_column_text][vc_column_text]