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TFE-M - Chemically Modified PTFE Shapes
To over come some of
the weaknesses of conventional PTFE , scientists has
developed the new chemically modified PTFE available as
Dupont's Teflon Nxt or Dalkin's TFM and have improved some of the
properties for the benefit of consumers
 Improvements At a Glance
- Less Creep
- Improved Permeation Resistance
- Smoother Surfaces
- Less Porous
- Better High Voltage Insulation
- New Fabricating Versatility with
welding
Chemically Modified
PTFE parts offers new opportunities for designing & engineering high performance
products to get following working advantages.
Improved Creep
Resistance
As PTFE
Gasketing & Sealing materials used in chemical process industries, due
to improved creep resistance & increased stiffness even at elevated
temperatures. The modified PTFE components can be used for higher
pressure conditions.
Enhanced
Permeation Resistance
The vessal linings,
Tubings, Sealing materials, Expansion joints, Made out of modified PTFE have
more life & less / near zero leakage due this enhanced permeation resistance.
Superior Surface
Finish
The Components,
surfaces made out of modified PTFE have superior surface finish with silky /
glossy surfaces. The components remain absolutely clean as there is virtually no
place for impurities to get a grip.
Reduced Porousity
The parts
made out of modified PTFE have low microvoid content, thus showing the
transmigration of aggressive liquids & gases through.
Better High Voltage
Insulation
Modified
PTFE allows better high voltage insulation giving new opportunities to
improve performance particularly in electrical applications.
Weldability
The
threaded joints / snug fit joints can be avoided by using directly
welded part to part, thus reducing the risk of leakage through
threaded joints.
Typical
Properties of Modified PTFE V/V Conventional PTFE
|
PROPERTY |
TEST METHOD |
UNIT |
Teflon
NXT |
PTFE |
|
Tensile Strength |
ASTM-D-4894 |
MPa (psi) |
31 (4,500) |
34 (5,000) |
|
Elongation at Break |
ASTM-D-4894 |
% |
450 |
375 |
|
Specific Gravity |
ASTM-D-4894 |
|
2.17 |
2.16 |
Deformation Under Load (Creep),
23oC (73oF) |
ASTM-D-695 |
% |
100 |
|
|
3.4 MPa (500 psi) |
|
|
0.2 |
0.7 |
|
6.9 MPa (1,000 psi) |
|
|
0.4 |
1.0 |
|
14 MPa (2,000 psi) |
|
|
3.2 |
8.2 |
|
Deformation Under Load (Creep), - DMA |
|
|
|
|
|
6.9 MPa (1,000 psi) at 25oC (77oF) |
|
|
5.3 |
6.7 |
|
3.4 MPa (500 psi) at 100oC (212oF) |
|
|
5.4 |
8.5 |
|
1.4 MPa (200 psi) at 200oC (392oF) |
|
|
3.6 |
6.4 |
| Void
Content of Typical Parts |
FTIR - Infrared
spectroscopy |
% |
Compression
Moulded: 0-0.5 |
Compression
Moulded: 0-1.5 |
Dielectric Strength, 76.2um
(0.003 in) Film |
ASTM-D-149 |
kV/mm
(V/0.001 in) |
32 |
24 |
| Weld
Strength ( Specimens welded after Sintering) |
ASTM-D-4894 |
% |
66-87 |
|
Comparative Permeation Rates For Modified PTFE & Conventional PTFE
|
Permeant |
Specimen
Thickness,
mm (in) |
Vapor |
Liquid |
Gas |
|
PTFE |
TFE-M |
PTFE |
TFE-M |
PTFE |
TFE-M |
|
Perchloroethylene |
1 (0.04) |
5.5 |
2 |
13 |
4 |
- |
- |
|
Perchloroethylene |
2 (0.08) |
1.4 |
0.1 |
0.019 |
0.005 |
- |
- |
|
Perchloroethylene |
3 (0.16) |
0.08 |
0.05 |
0.006 |
0 |
- |
- |
|
Perchloroethylene |
4 (0.20) |
0.055 |
0.050 |
- |
- |
- |
- |
|
Hexane |
5 (0.08) |
3.4 |
0.2 |
23.4 |
0 |
- |
- |
|
Hexane |
6 (0.20) |
0.045 |
0.015 |
- |
- |
- |
- |
|
MEK |
7 (0.08) |
36.3 |
23.3 |
49.4 |
34.2 |
- |
- |
|
MEK |
8 (0.20) |
22.6 |
20.8 |
35.5 |
25.2 |
- |
- |
|
HCI, 20% |
9 (0.04) |
0.4 |
0.1 |
- |
- |
- |
- |
|
Helium |
10 (0.08) |
- |
- |
- |
- |
93 |
1 |
|
Helium |
11 (0.20) |
- |
- |
- |
- |
0.18 |
0.12 |
Applications:
Due to superior properties
of TFE-M to conventional PTFE, the typical application of TFE-M
includes Pumps Diaphragms (Improved permeation), Ball Valve Seats
(Improved Creep Resistance), Components of Mechanical Seals
(Improved permeation and surface finish), Dipped Pipes for reaction
vessels (Improved surface finish and weldability), Vessel Lining
(Improved permeation and weldability)
Product Range :
All the products mentioned
in 'FLUSTOX' can be made available in TFE-M
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