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General procedures to determine the composition of commercial, two‐part polysulfide aircraft sealants
Author(s) -
Ennis Brian C.,
Hanhela Peter J.,
Huang Robert H. E.,
Long Geoffrey J.,
Paul D. Brenton
Publication year - 1990
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1990.070411126
Subject(s) - polysulfide , sealant , curing (chemistry) , adhesive , materials science , polymer , dispersant , chemistry , chemical engineering , polymer chemistry , composite material , electrode , layer (electronics) , electrolyte , engineering , physics , optics , dispersion (optics)
Interpretation of the chemical processes which polysulfide sealants undergo either on storage or when the cured material is subjected to environmental influences requires detailed knowledge of formulations. Procedures have been developed to isolate and identify a range of additives in two‐part commercial aircraft sealants of both the dichromate and manganese dioxide cure types. Solvents, curing agent dispersants, and cure rate modifiers were separated chemically and thermal analysis was demonstrated to provide a ready means to estimate carbon in fillers. The phenolic resin adhesion enhancers were conveniently determined using 13 C‐NMR spectroscopy and could also be identified using size exclusion chromatography. It was shown that virtually no interaction occurred between polysulfide liquid polymers and phenolic resins following aging at 70°C for 7 days. The most appropriate methods for determining curative levels were established and new means of assessing thiol content of the polysulfides by both 13 C‐NMR and PMR spectroscopy are described. The significance of aspects of the sealant formulations is discussed.