Properties of Unfilled and Filled PTFE
 
     
 
Property
Unit
Test Method (ASTM)
100% Pure PTFE
25% Carbon Filled PTFE
25% Glass Filled PTFE
15% Graphite Filled PTFE
40% Bronze Filled PTFE
60% Bronze Filled PTFE
Specific Gravity
-
D 1457
2.14 - 2.18
2.08 - 2.1
2.22 - 2.25
2.13 - 2.18
3.1 - 3.22
3.85 - 3.95
Bulk Density
g/1
D 1457
700 + 100
500 + 40
475+ 50
500+ 40
900 + 50
1050 + 50
Tensile Strength
kg/cm2
D 1457
250 - 310
160 - 175
130 - 150
140 - 210
180 - 240
125 - 150
Elongation at Break
%
D 1457
280 - 300
80 - 110
210 - 270
100 - 180
240 - 320
150 - 200
Hardness
Shore D
D 2240
50 - 65
71 - 73
66 - 68
62 - 65
67 - 69
71 - 73
Coeff. of Friction
--
LNP Std.
0.06
0.13
0.12
0.07
0.12
0.13
Deformation after 24 Hours at 230C 140 kg/cm2C
%
D-621
15
5
11
9
5
5
Deformation after 24 Hours at 2600C 40 kg/cm2
%
D-621
31
11
21
16
14
12.5
Flexural Strength
kgf/cm2
D-790
57
96
42
63
-
80
Impact Strength
Cmkg/cm2
D-256
-
-
-
-
-
-
A - 200C
-
-
9
7.5
9.5
-
-
11
B - 200C
-
15
10
11
-
-
10
Dielectric Strangth
KV/mm
D-149
24
2
12
-
Conductive
Conductive
Volume Resistivity
Ohm-cm
D-257
1010
104
1015
1014
-
1017
Surface Resistivity
Ohm
D-257
1017
107
1015
1014
-
109
Heat Resistance
0C
-
-250 to 260
-250 to 260
-250 to 260
-250 to 260
-250 to 260
-
Thermal Conductivity
10-4Cal.
Cm.Sec. Deg.
Cento Fitch
6
13
9
11
-
19
Linear Expansion
%
D-696
Axial  Redial
Axial  Redial
Axial  Redial
Axial  Redial
Axial  Redial
Axial  Redial
A 30 to 1500C
-
-
1.5     1.5
1.2      1.0
1.2      1.5
-
-
1.1      0.9
B 30 to 2000C
-
-
2.4     2.4
1.9      1.5
2.2      1.0
-
-
1.8      1.5
C 30 to 2500C
-
-
3.4     3.6
2.7      2.4
3.2      1.4
2.15     1.6
-
2.5      2.2
Chemical Resistance PTFE is almost completely chemically inert material. Molten or dissolved alkali metals degrade PTFE by abstracting fluorine from the molecule. Apart from these PTFE resin is not at all attacked by any of the acids, bases and slovents.
Filled PTFE has inferior chemical resistance because of the presence of the particular filler.