New Approaches to Maximizing Thermo-oxidation Resistance of Polycyanurate Networks
AIR FORCE RESEARCH LAB EDWARDS AFB CA
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Among thermosetting resins, polycyanurate networks derived from cyanate ester monomers offer excellent flame, smoke, and toxicity characteristics along with enhanced thermo-oxidative stability compared to epoxy resins. Recent structure-property investigations in polycyanurate networks have revealed new insights into the relationship between the chemical moieties found in the networks and the corresponding levels of thermo-oxidative resistance. In particular, it appears that the presence of methyl groups next to tertiary or quaternary carbons has a decidedly negative impact on thermo-oxidative stability during TGA heating ramp tests. In the case of silicon-containing cyanate esters, thermo-oxidative stability can be improved significantly by the incorporation of silicon only in cases where either a large portion of the chemical repeat unit is formed from inorganic groups, or the thermo-oxidative stability of the carbon-containing analog is relatively poor compared to other organic polycyanurate networks.
- Organic Chemistry