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technical guide

fluoroplastic guide

Fluoroplastics are a range of very unusual and uncommon plastics, here is a simple guide.

 

Fluoroplastics is a technical word given to a group of plastics where the molecules contain carbon and fluorine. The plastic polythene is a molecule consisting of a carbon chain with hydrogen atoms attached.

Polytetrafluoroethylene (PTFE) is much the same but with the hydrogen atoms replaced by fluorine atoms. The replacement of the hydrogen atoms with fluorine atoms dramatically changes the properties of the material, and fluoroplastics therefore tend to have special properties:

  • Very high working temperatures

  • Non-stick characteristics

  • Very high resistance to chemical and solvents

  • Very high electrical resistance

This information is very general and at Adtech we are very keen to discuss the properties of these materials and to select the best one for your application. There are many subtle differences in these plastics which, if chosen carefully, can give great price/ performance benefits.

Polytetrafluoroethylene - PTFE

Trade names: Teflon®, Fluon, Hostaflon.

PTFE is the grandfather of all fluoroplastics. It is the most unusual and exhibits the best performance in terms of temperature, chemical resistance and non-stick properties.

Its major disadvantage is that it does not actually melt when heated and therefore is difficult to process, and very unconventional techniques are needed to mould, extrude and weld this fluoroplastic.

Teflon® is the registered trademark of Chemours, previously known as Du Pont de Nemours.

Fluoroethylenepropylene - FEP

Trade name: Teflon®

FEP is mainly manufactured by Daikin and Chemours and was developed as a ‘melt processable’ version of PTFE. That is, it can be processed by normal plastic methods. It has basically similar properties to PTFE but a lower maximum operating temperature of 200°C instead of 260°C.

 

Perfluoralkoxy - PFA

Trade name: Teflon®

PFA was developed as a high temperature version of FEP. Generally, PFA fluoroplastics have similar properties to FEP but can be used at temperatures up to 260°C. It is very expensive!

Teflon® is a tradename of Chemours, previously known as Du Pont de Nemours.

Ehtlyene Tetrafluoroethylene Copolymer - ETFE

Trade Name: Tefzel

Du Pont developed ETFE as a ‘tough' fluoropolymer. It is a normal thermoplastic, but it is much harder than PTFE and FEP and similar in hardness to Nylon and is therefore used as an ‘engineering' plastic.

The improvement in stiffness is paid for by reduced chemical resistance and working temperature.

 

Ehtylene Chlorotrifluoroethlyene - E-CTFE

Trade name: Halar

E-CTFE is a tough plastic with similar properties to ETFE and used mainly for its chemical resistance.

Polyvinylidene Fluoride - PVDF

Trade names: Kynar, Solef

PVDF is a very hard plastic roughly comparable to E-CTFE and relatively cheap compared with other fluoroplastics. It has good chemical resistance, but not as good as C-TFE and ETFE.

 

Polyvinyl Fluoride - PVF

Trade name: Tedlar®

PVF is again a hard tough fluoroplastic with limited chemical and temperature resistance. It is normally used as a film in gas bags, solar heating panels and printing circuit laminating.

Tedlar® is a tradename of Chemours, previously known as Du Pont de Nemours.

Chemical & Technical Properties 

Fluoroplastics, known as the noble plastics, are some of the most inert materials known to man. They are unaffected by all chemicals, and certainly most chemicals in industrial use. The few chemicals that are known to have an effect are:

  • Sodium metal

  • Potassium metal, in liquid form or as reactive complexes which are, in effect, liquid solutions of these metals

  • Fluorine and related oxidising compounds, such as chlorine trifluoride at elevated temperatures

There is no known solvent for PTFE, FEP or PFA.

Fluoroplastic Technical Properties

 
PTFE 
FEP 
PFA 
ETFE
Tensile strength (kp/cm³) 250 210 280 450
Elongation (%) 350 300 300 200
Flexural modulus (kp/cm²) 6800 6800 1400 1400
Hardness D55 D55 D55 D75
Melting point (°C) +327 +279 +305 +270
Max service temp. (°C) +260 +200 +260 +150
Low service temp. (°C) -200 -200 -200 -200
Non flammability 94 VO 94 VO 94 VO 94 VO
Water absorption 20°C (%)  <0.01 <0.01 <0.01 0.01
Weather resistance Excellent Excellent Excellent Excellent
Density (g/cm³) 2.1 2.1 2.1 1.7
Dielectric constance (MHz) 2.1 2.1 2.1 2.6
Dissipation factor 0.0002 0.0002 0.0002 0.0008
Organic solvent resistance Excellent Excellent Excellent Excellent
Acids & alkalies resistance Excellent Excellent Excellent Excellent
Flexibility Excellent Good Good Good
Radiation resistance (rad) 10-5 10-6 10-6 10-8
Specific heat (cal/g/°C) 0.3 0.28 0.29 N/A
Thermal conduct. (cal.sec.sq cm/°C/cm) 5 x 10-4 5x 10-4 5 x 10-4 N/A
Linear expansion coef. (cm/cm/°C) 10-4 9 x 10-5 14 x 10-5 9 x 10-5
Friction coef. (dynamic to steel) 0.1 0.2 0.2 0.3

 

Plastics Maximum Operating Temperatures

IMPORTANT NOTE: This data is intended as a guide and is taken from resin manufacturers' data. Adtech cannot take responsibility for the accuracy of the data, and customers must evaluate the material under the relevant conditions if the properties are critical to their applications.

We understand that every customer’s requirements are different, so our customer service and R&D teams are on hand to discuss your project:

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