Elastomers can swell and/or degrade in chemical
seal environments through reactions with the polymer backbone and cross-link
system, or by reactions with the filler system. In the semiconductor industry,
this degradation can be seen in increased contamination and reduced seal life.
Polymer Backbone and Cross-link:
Polar Attack
Nucleophilic Attack-main mechanism for
cross-linking. However, when it occurs in chemical media, it may lead to
excessive cross-linking and embrittlement.
Dehydrofluorination-attack resulting in the
formation of unsaturated bonds on the fluorocarbon backbone. It can be caused
by the attack of primary and secondary aliphatic amines.
Filler System:
Oxidation—degradation of carbon black fillers
Chemical Attack—i.e., HF acid attack of silica
fillers
Special Considerations:
Contamination
Particle Generation
Elemental Extractables
Residual Gas Contamination
Special Chemical Environments:
Plasma Resistance
Vacuum—volatile condensable material
(VCM) 125°C 10-6 Torr JPL
Test Methods:
ISO 1817 (Liquids)
ASTM D471, D1460, D3137 (Liquids)
Volume Swell
The most common measure of chemical compatibility
for a chemical seal is volume swell. The following formula is used in reporting
volume swell measurements. This takes into account dimensional changes in all
three dimensions, and is more relevant than specific dimensional change readings
for a chemical seal.
Contact Us : www.indiarubberdirectory.com C/o Team Web Power, No.52, First Floor, Anna Nagar Plaza, C-47, IInd Avenue, Anna
Nagar, Chennai 600040. India.
Phone:- +91-44-42170137 Mobile:- +91-9444001705