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PTFE
Structurally, there are different types of TeflonŽ
resin. TeflonŽ PTFE resin is a polymer consisting of recurring tetrafluoroethylene
monomer units with the formula: (CF2-CF2)n
The maximum molecular weight of this greater than 90°/0 crystallinic
TFE Polymer is about 9x106. PTFE displays a series of unique properties:
Nearly universal chemical resistance (exceptions: elemental fluorine,
CF3, molten alkali metals) Insoluble in all solvents below 300°C
High service temperature stability up to 250°C Very low adhesiveness
Very low friction coefficient Extremely hydrophobic Physiologically
inert, contaminant free Very good electrical (high resistance) and
dielectrical (very low dielectric number and loss factor) properties
Nonflammable Highly weather resistant (UV resistant) Good mechanical
properties: tough elastic, easily manufactured
These advantages of PTFE, especially its universal chemical resistance,
are the reason labware and accessories made of PTFE or other fluorocarbon
resins are a must in any laboratory. Its broad service temperature
range and its unbreakability are further advantages of PTFE.
Stirrer blades, magnetic stir bars encapsulated in PTFE, joint sleeves,
adapters and boiling accessories are just a few of the items available
in PTFE along with standard Labware
items such as Flasks,
Bottles, Beakers,
etc. They are indispensable if the chemical resistance of glass
or rare metals does not suffice. Digestion in boiling hydrofluoric
acid or boron trifluoride is possible as well as hot alkali-hydroxide
melts.
Labware made of PTFE resists temperatures of -200°C without becoming
brittle. The maximum service temperature is +250°C, (but 300°C is
possible) for a short time period. PTFE is extremely nonadhesive.
This is an advantage for working with lacquers, adhesives, resins
and hydroscopic substances. PTFE is biologically inert. Therefore
it is used in many applications in biology, microbiology, medicine,
pharmacy and in the food industry.
Pure PTFE, because of its chemical resistance and its antiadhesive
surface, prevents any sample contamination by abrasion or etching.
Vessels made of PTFE therefore are absolutely necessary in trace
element analysis methods.
The production of PTFE-ware is performed using the so called isostatic
pressing process. PTFE powder is filled in forms and isostatically
pressed at high pressures. The pressed parts are sintered at temperatures
up to 400°C. The characteristics of the material are substantially
influenced by the pressing and sintering process. Porous PTFE is
made by controlled sintering of powders with defined particle sizes.
Stock PTFE in rods, sheets, etc. are available for customer use.
PTFE : TeflonŽ, Hostaflon,
Malon, Fluon, Polyflon
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