Ambient Temperature Cure Catalysts for Carboxy Binder Systems. Selection and Evaluation of Catalysts for the Ambient Cure of Epoxy-Carboxy Binders.
Interim technical rept. 1 Jan-15 Aug 70,
MIDWEST RESEARCH INST KANSAS CITY MO
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An extensive series of organometallic compounds and metal carboxylates are being screened to determine their utility as catalysts for the ambient temperature cure of carboxylic acid-epoxide binders. Chromium salts have thus far been found to be the most effective, giving complete and stoichiometric reaction at the 1 level at 25C in less than 7 days in both model studies and binder cure reactions. Iron salts, notably ferric octoate, give good rate control up to approximately 75 conversion after which there is a deviation in stoichiometry epoxide is consumed faster than acid and apparent destruction of the catalyst. All other materials examined were poor ambient temperature catalysts for the epoxide-carboxylic acid reaction. Chromium 2-ethyl hexanoate octoate has been selected for primary evaluation in the carboxylic acid-epoxide binder propellant studies. The Telagen prepolymer was found in gumstock studies to cure at ambient temperature with the tri-epoxide ERLA 0510 in 1 week with 0.40 and in 2 weeks with 0.37 chromium octoate cure catalyst. Several 1-lb. propellant mixes containing 14.5 binder were processed and cured successfully at 26C 79F. Author
- Solid Rocket Propellants