Effects of Silicon Substitution in the Main Chain Network Segments of Polycyanurates
Abstract
The incorporation of silicon into thermosetting polymers at the molecular level has been shown to have several significant effects, beyond improving thermo-oxidative stability, as demonstrated by studies of silicon-containing cyanate ester resins. These effects are generally traceable to the enhanced flexibility afforded by the substitution of C-Si and C-C bonds, and include increased free volume and thermal expansion. In cyanate esters, the increased specific volume leads to a decrease in cyanate ring density, which may explain the reduced water uptake in silicon-containing cyanate esters at high conversions. In addition, the increased flexibility provides for a greater degree of cure at lower temperatures than would otherwise be possible, leading, counterintuitively, to a higher glass transition temperature for a given cure schedule. Due to the molecular level mechanisms involved, many of these effects are expected to be present in other silicon-containing thermosetting resins as well.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 29, 2011
- Accession Number
- ADA555878
Entities
People
- Andrew J. Guenthner
- Joseph M Mabry
- Josiah T. Reams
- Kevin R. Lamison
- Vandana Vij
Organizations
- Air Force Research Laboratory