Fluoroplastics are unusual and very uncommon plastics. So here for the layman is a simple guide to what’s what in the fluoroplastic world.
Fluoroplastics is a clumsy 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. PTFE is much the same but with the hydrogen atoms, the hydrogen atoms are replaced with 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.
The more common members of the fluoroplastics family, with which we work, are:-
PTFE is the grandfather of all fluoroplastics;, it is the most unusual and exhibits the best performance in terms of temperature and 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 fluoroplasticit.
This fluoroplastic is mainly manufactured by Du Pont Co,. and was developed as a ”melt processable” version of PTFE. That is, it can be processed by normal plastic methods. It has basically very similar properties to PTFE, but has a lower maximum operating temperature of 200°C instead of 260°C.
PFA (Per Fluor Alkoxy)
PFA was developed as a high temperature version of FEP – generally it has similar properties but it can be used at temperatures up to 260°C. It is very expensive!
ETFE (Ethylene Tetra Fluoro Ethylene Copolymer)
Du Pont developed this material fluoroplastic as ”Tough Teflon”. It is a normal thermoplastic but it is much harder
than PTFE & 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.
E-CTFE (Ethylene-Chloro Tri Fluoro Ethylene)
A tough fluoroplastic with similar properties to ETFE. Used mainly for its chemical resistance.
PVDF (Poly Vinylidene Fluoride)
Very hard plastic roughly comparable to E-CTFE and relatively cheap compared with other fluoroplastics. Good chemical resistance, but not as good as C-TFE and ETFE.
PVF (Polyvinyl Fluoride)
Again a hard, tough fluoroplastic with limited chemical and temperature resistance. Normally used as a film in gas bags, solar heating panels, printing circuit laminating, etc.
The above information is very general as there are many subtle differences in these fluoroplastics, which, if chosen carefully can give very great price and/ performance benefits.
Post time: 06-09-2017