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Properties of PTFE (Teflon)

PTFE (Teflon®) – Polytetrafluoroethylene

A Conbination of Carbon and Fluorine (Fluorocarbon) discovered in April 1937 by DuPont Chemist Dr Roy Plunket, generally known as Teflon

A Special Plastic

PTFE belongs to the Flouropolymers family. Polymer means many parts, and these parts bond to form a “long chain” fluorocarbon. The chemical formula for the PTFE molecule is CF2, CF2 n (“n” means “repeated many times”). C represents one atom of carbon. and F2 represents two atoms of fluorine. Fluorine has very low surface energy, giving PTFE its low coefficient of friction, and fluorine is chemically inert. Chemical bonds between atoms in the PTFE molecule play a critical role in PTFE properties because they provide powerful binding forces. The two forces bonding the PTFE molecular structure are the carbon-to-carbon bonds, which forms the backbone of the polymer chain, and the carbon to fluorine bond, which forms the shield.

Both bonds are very strong and enhance PTFE’s unique properties. Notice that the fluorine atoms are larger than the carbon atoms.  These powerful binding forces produce a PTFE molecule with a fluorine shield around the carbon backbone. As this graphic illustrates, the carbon backbone is completely surrounded and enclosed by large, chemically inert fluorine atoms, creating a protective shield or sheath. This provides PTFE with the following properties and benefits:

PTFE Coated composite Materials

When PTFE (Teflon®) is coated onto woven composite materials such as Glass, Kevlar® and Nomex®, they exhibit all the properties and characteristics of the PTFE with the added advantage of the dimensional stability and tensile strength of the woven substrate

Unparalleled Temperature Range -73 to +260 DegC

With such a broad operating temperature range, PTFE coated composite material has found itself in applications ranging from the dark and forbidding environment of Space to Contact Frying of Food.  Within this temperature range the characteristics are unchanged.For this reason design engineers are constanly finding new and ever more demanding applications where no other man made material would be suitable.The stated temperature range is the constant, contact temperature that the material can operate within.  This is to say the actual temperature of the material, not the operating environment.  The material will in fact operate in a much broader temperature range (-173°C to +300°C) dependant on the exact product in terms of substrate type and coating level.  

 

 

UV, IR, RF & Microwave Resistant

PTFE is unaffected by the almost the entire electro magnetic spectrum.  This has lead to the widespread use of PTFE coated composite material in the harsh environment of space.  Many of the layers that make up the EVA Space suits worn by Astronauts are made form these fabrics.  The microwave transparency of these fabrics is put into use for transmitters on Point-to-Point communication towers and Radome covers for Radio Telescopes.  Within a high UV environment such as a sunny climate, PTFE coated material will fade (UV Bleaching) but will otherwise be unaffected.  The damage caused by super high levels of UV as within industrial processing such as Screen Print Dryers will be to the substrate itself.  To avoid this, the PTFE coating can be filled with UV blocking pigments.

Weather Resistant

PTFE Coated Composite Materials can be made completely Weather Resistant with a guaranteed lifespan of 25 years.  For over thirty years this technology has been allowing architects the world over realise their dreams.  With up to 50% lights transmittance and with strength to weight ratios exceeding that of steel. These fabrics are proving themselves to be a great asset in the world of construction, in terms of Cost, cosmetic appearance and environmental efficiency.

 

Low Thermal Mass

PTFE coated composite materials have a very low thermal mass when compared to materials such as Steel.  In the baking of croissants the energy saved is dramatic: 1,310 KCal/h Vs  82,992 KCal/h for a Steel Belt.  For this reason they are extensively used in a broad spectrum of industries, wherever efficiency in thermal transfer is required.

Dimensional Stability

PTFE is not an inherently strong substance, however when coated onto woven substrate such as Glass, Kevlar® and Nomex® it takes on the dimensional and tensile strength of the particular substrate.  Kevlar® for example is weight for weight, five times stronger than Steel.  This has lead to the replacement of many steel products from process conveyor belting within the Food Industry to Roof membranes being replaced by these PTFE coated composite materials.