Curing and Characterization of Siloxanecarbonate Polymers
Abstract
Several synthetic procedures were explored to prepare a curable form of the AFML-developed siloxanylenearylene carbonate polymer designated POLYSAC. A method for introducing vinyl groups into the tetrasiloxane portion of the polymer was perfected. Modified curable POLYSAC polymers containing 5, 10, 14, 20, and 30 percent vinyl groups on the tetrasiloxane part of the polymer were synthesized. Several methods of polymerization for achieving high molecular weight were investigated. Condensation (chain extension) of monomers to a molecular weight of up to 11,000 and inherent viscosity of 0.18 dl/g was achieved with 2, 4, 6-trimethylpyridinium trifluoroacetate as catalyst. The polymer from this process had a yellow color and was transparent. In contrast, inherent viscosities up to 0.38 dl/g were achieved with the HRTTT process. The polymer produced by the latter process was colorless but was somewhat translucent. Curing studies with free radical initiators were conducted on the vinyl-modified POLYSAC. The best cure observed was with dicumyl peroxide as initiating agent. Mechanical tests on cured polymer indicated highest tensile strength from samples cured for two hours at 149 C and post cured for 16 hours at 200 C. Thermal analyses (TGA) on the various modified POLYSAC polymers showed onset of degradation temperatures varying from 375 C to 410 C, with most samples clustering at 380 C.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1980
- Accession Number
- ADB046093
Entities
People
- Charles D. Beard
- D. Patrick Salisbury
- Danute I. Basiulis
- Katherine M. Hughes
- Norman Bilow
Organizations
- Hughes Aircraft Company