Ambient Temperature Binder Cure Catalysts for Hydroxy Terminated Systems.
Abstract
Numerous cure failures have been encountered in the search for catalysts which will provide ambient temperature cures for hydroxyl terminated polybutadiene propellants. These cure failures have been found to be due to side reactions which affect the stoichiometry of the reacting species and play a more dominant role than higher cure temperatures. The two most important side reactions which can lead to cure failure and/or degraded mechanical properties are the moisture-isocyanate reaction catalysts. Tetravalent alkyltin-salts like dibutyltindilaurate and dibutyltindiacetate accelerate the moisture reaction approximately ten times more than Fe(AA) in uncatalyzed mixtures of the reactants, while the urethane reaction is accelerated more efficiently by metal catalysts. Divalen tin, lead and copper derivatives were found to be the strongest homopolymerization catalysts. With the exception of Cu-compounds this homopolymerization is strongly suppressed by ammonium perchlorate. A potential cure system using isocyanate trimerization as a crosslinking reaction has been abandoned because of extremely poor mechanical properties. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1970
- Accession Number
- AD0872870
Entities
People
- Adolf E. Oberth
- Edmund J. Mastrolia
Organizations
- Aerojet Rocketdyne Holdings