What is Kynar® Plastic? — PVDF Plastics for Flow Control Parts

Last updated on March 22, 2021

Learn why Kynar® and PVDF plastic might be the best material choice

A black Kynar® (PVDF) plastic PBV3 series three-way ball valve.
Kynar® (PVDF) plastic
three-way ball valve
What is Kynar® Plastic?

Kynar® is Arkema's trade name for their PVDF plastic. PVDF or polyvinylidene difluoride plastic is a tough, stable, very non-reactive thermoplastic.

PVDF is a useful engineered plastic because it has important advantages over other plastics: strength, durability, abrasion resistance, low permeability, recyclable and more.
 

What is PVDF plastic?

Technically, PVDF is a semi-crystalline high-performance thermoplastic.



Semi-crystalline plastics

Semi-crystalline plastic materials have a very organized molecular structure and sharp melting points. This means that they do not gradually soften as their temperature increases. Instead, they stay solid until their melting point is reached. When they are hot enough, semi-crystalline plastics quickly change from solids into low viscosity or thin liquids that flow easily.

PBV3 series three-way ball valves from ISM are available in black Kynar® (PVDF) plastic >>

A simplified diagram illustrating the basic difference between amorphous and semi-crystalline thermoplastics.
Amorphous vs semi-crystalline
thermoplastics

Learn more about amorphous vs. semi-crystalline thermoplastics at Redwood Plastics and Rubber >>

Typically, semi-crystalline thermoplastics melt and flow at temperatures ranging from about 275º to 335º F (135º to 335º C). The specific melting point depends on the type of plastic.
 

Thermoplastics

Thermoplastics are useful for making products because they can be heated until they melt and flow. After cooling, thermoplastics become hard again.

This cycle of melting, reforming and cooling can be repeated again and again. Injection molding is a production process that takes advantage of this. It can be used to quickly and economically produce large numbers of consistently high-quality thermoplastic parts.
Learn more about thermoplastics at AZO Materials >>

A natural Kynar® (PVDF) plastic male luer thread to male luer thread connector fitting.
Kynar® (PVDF) plastic luer fitting

Kynar® (PVDF) plastic luer fittings are available at ISM >>


Fluoropolymers

PVDF is also a fluoropolymer. Fluoropolymers are polymers or plastics that have multiple carbon-to-fluorine bonded sections inside each molecule. Fluoropolymer plastics are very resistant to solvents, acids, and bases.

PVDF is also FDA compliant and completely non-toxic. This means it can be used in repeated contact with food.

Kynar® (PVDF) plastic tubing.
Kynar® (PVDF) plastic tubing

Kynar® (PVDF) plastic tubing from ISM >>

What chemicals are PVDF plastics resistant to?

 

  • Bases
  • Ozone
  • Alcohols
  • Mineral acids
  • Organic acids
  • Halogenated solvents
  • Aromatic hydrocarbons
  • Aliphatic hydrocarbons
  • Oxidizing environments
     

Check out the Chemicals and chemistry resources section at the end of this article >>
There is more information about these chemical groups below plus links to in-depth descriptions at highly reputable sources.

Learn more about chemical compatibility and get a copy of the ISM PVDF (Kynar®) Chemical Compatibility Chart >>

Black Kynar® (PVDF) plastic spring-loaded check valve. This is an ISM CVSC series 1/8” hose barbed lightweight check valve.
Kynar® (PVDF) spring-loaded check valve

Black Kynar® (PVDF) plastic CVSC series lightweight spring-loaded check valves from ISM >>

These are the key useful characteristics of PVDF plastics:
  • Low weight
  • Recyclable
  • High Strength
  • Good toughness
  • Weather resistant
  • High heat resistance
  • Good electrical insulator
  • Good chemical resistance
  • Slippery or low coefficient of friction
  • Low permeability to most gases and liquids

 

What does is really mean to describe Kynar® or PVDF as a tough plastic?
  • Good endurance
  • Radiation resistant
  • Mechanically strong
  • High abrasion resistance
  • Good resistance to stress cracking
Black Kynar® (PVDF) plastic high strength spring-loaded check valve. This is an ISM CVS series 3/8” hose barbed check valve.

Kynar® (PVDF) high strength spring loaded check valve

Kynar® (PVDF) plastic CVS series high strength spring loaded check valves from ISM >>
 

What is stress cracking?

Environmental stress cracking is when a thermoplastic fails after it has been exposed to certain chemicals. This failure is not the direct effect of being exposed to a particular chemical. Instead, stress cracking is caused by a combination of

  • A plastic’s susceptibility to stress cracking
  • Its exposure to a chemical that causes stress cracking
  • The mechanical stresses caused by pulling or tugging on the material

Chemicals that can cause stress cracking include detergents, surfactants, lubricants, oils, ultra-pure water and plating additives such as brighteners and wetting agents.
Learn more about stress cracking at ISM’s Chemical Compatibility Chart landing page >>

Natural Kynar® (PVDF) plastic tubing connectors. These are ISM VC series barb-by-barb straight flexible plastic tubing connectors.
Kynar® (PVDF) straight
plastic tubing connectors

Kynar® (PVDF) plastic VC straight tube connectors from ISM >>

 
So, why use Kynar® and other PVDF plastics?

PVDF is a strong, tough, durable plastic. Its abrasion resistance is greater than other plastics and even some metals. It does not leach any chemicals and is highly resistant to a broad range of chemicals.

Using Kynar and PVDF plastic components is the right choice when it is important to prevent system failures due to weathering, stress cracking, abrasion and chemical corrosion.


References for much more in-depth chemical and technical details about PVDF plastic

Check out the Polyvinylidene Fluoride (PVDF) Complete Guide at SpecialChem >>

Check out the PVDF Properties and Their Values pate at SpecialChem >>

Get a copy of our PVDF (Kynar®) Chemical Compatibility Chart >>

 

Get the Chart >> 

This reference chart provides guidelines for evaluating PVDF compatibility with a wide range of chemicals used in industrial, commercial and laboratory applications >>

Back to the “What chemicals are PVDF plastics resistant to?”

 

Chemicals and chemistry resources


Alcohols

Alcohols are organic compounds with a hydroxyl group attached to one end of the molecule. Hydroxyl groups are one hydrogen atom bonded or attached to an oxygen atom.
Get more information at the Alcohol page from Encyclopædia Britannica >>

 

Bases

Bases are the opposite of acids. Like acids, bases also tend to be very corrosive depending on the specific chemical and how concentrated it is. Lye is a strong base that most people are familiar with.
Get more information at the Base page from Encyclopædia Britannica >>

 

Mineral acids

Sulfuric acid, hydrochloric acid and nitric acid for example. Mineral acids are acids made from an inorganic compound. These acids easily dissolve in water and are highly acidic.
Get more information at the What is a Mineral Acid page from ThoughtCo >>

 

Organic acids

Carboxylic acids and sulfonic acids are organic acids. These acids are organic compounds that have acidic properties: liquids, corrosive and so on. Organic acids tend to be weak acids and do not dissolve completely in water.
Get more information at the Organic Acid page from Wikipedia >>

 

Halogenated solvents

Chloroform, carbon tetrachloride, and methylene chloride are examples of halogenated solvents. These solvents are compounds that contain halogen atoms (see below).

 

Aromatic hydrocarbons
A rendered two-color 3D model of the benzene ring molecule.
Benzene ring

Benzene is an aromatic hydrocarbon. These chemicals are organic compounds that contain one or more benzene rings. A benzene ring is a hexagonal ring of six carbon atoms.
Get more information at the Aromatic Hydrocarbon page from Wikipedia >>

 

Aliphatic hydrocarbons

Methane, acetylene, and ethylene for example. Aliphatic hydrocarbons are organic compounds whose atoms do not link together to form a ring.
Get more information at the Aliphatic Hydrocarbon Definition page from ThoughtCo >>

 
Oxidizing environments

Oxygen, hydrogen peroxide and the halogens are examples of oxidizers. In the Earth's atmosphere, iron is converted to iron oxide or rust because there is plenty of oxygen available.
Get more information at the Oxidizing Agent page from Wikipedia >>

 

Halogens

Halogens are the group non-metallic elements that includes fluorine, chlorine, bromine and iodine. These elements are poisonous and are highly chemically reactive.
Get more information at the Halogen page from Wikipedia >>

Back to “What chemicals are PVDF plastics resistant to?”

 

Steven C. Williams headshot March, 2018.

About the author
Steven C. Williams my LinkedIn profile link button.
Steven C. Williams, BS, is the technical writer and an inbound marketing specialist at Industrial Specialties Manufacturing (ISM), an ISO 9001-2015 supplier of miniature pneumatic, vacuum and fluid circuitry components to OEM's and distributors all over the world. He writes on technical topics related to miniature pneumatic and fluidic components as well as topics of general interest at ISM.       


« Go back to the blog homepage