| ASTM
D1418 |
Accepted
Synonyms or Trade Names |
Chemical
Makeup |
Comments |
Mode
of Failure |
Relative
Material Cost |
| NBR |
NitrileBuna-N |
Copolymer
of butadiene and acrylonitirle |
Versatile,
good processing. Acrylonitrile contents range 18% (good
low temperature)to 50% (good oil and heat resistance).
Many options for cure systems. Unsaturated. |
Usually
Hardening |
1.0 |
| XNBR |
Carboxylated
Nitrile |
Copolymer
of butadiene and acrylonitrile with additional acid eater
groups |
Additional
cross-linking sites improve some physical properties.
Processing impaired. Unsaturated. |
Usually
Hardening |
1.2 |
EAM
(Unofficial) |
Vamac |
Copolymer
of ethylene, methyl acrylate and a monomer to facilitate
vulcanization |
Essentially
saturated. Fair low temperature properties. Fail low temperature
properties. Fair oil resistance. Poor/fair processing.
Few cure and viscosity options available. |
Usually
Hardening |
2 |
| ACM |
Acrylate
PA |
Copolymers
of various acrylates and a monomer to facilitate vulcanization. |
Essentially
saturated. Recent versions have fair (-40oC) low temperature
properties. Poor to fair processing. Few viscosity variations.
Few cure system options. |
Wear
and/or Hardening |
2.5 |
| VMQ |
Silicone |
An
organo-siloxane polymer with substituent vinyl and methyl
groups. |
Saturated.
Low tear strength, thermally stable and heat resistance
in dry state. Good low temperature properties. Swell high
in petroleum fluids, but reversible with temperature.
Easy processing. |
Usually
Reversion |
6 |
| FKM |
Fluoro-elastomerViton
Fluorel |
Copolymer
of vinylidene fuoride and perfluoro-propylene. |
Saturated.
Resistant to a variety of fluids. Fair low temperature
properties. Thermally stable and heat resistant without
reversion. Poor/fair processing. Some viscosity variations
available. |
Usually
Set, With Varnish Buildup |
20 |
| HNBR |
Highly
saturated Nitrile. |
NBR
with double bonds removed through saturation process. |
Good
abrasion, oil, and EP additive resistance, Good high and
low temperature performance. |
Set,
Varnish Buildup |
15 |
| PTFE |
Teflon |
Poly
Tetra Fluoro-ethylene |
Excellent
Oil & chemical resistance excellent temperature range.-50
to 300 oC |
-- |
25 |
