The Preparation and Properties of D2-m-Carboranesiloxane Polymers.
Abstract
Linear D2-m-carboranesiloxane polymers (Mw = 150,000-250,000) were prepared from 1,7-bis(hydroxydimethylsilyl)-m-carborane and bis(n-phenyl-N',N'-tetra-methyleneureido)dialkylsilanes as condensation monomers. Improved methods of monomer preparation and purification were developed. The polymers exhibit outstanding high temperature stability and retention of elastomeric behavior. The preferred central silicon substitution pattern is 67% dimethyl-33% methyl-phenyl. Filled and cured vulcanizates gave long-term elastomeric performance from -25 C to = or > 300 C. The preferred fillers are hydrophobic silicas, the preferred curing agents are peroxides, and the preferred antioxidant is ferric oxide. Radiation resistance, flammability, and solvent resistance were evaluated; 3,3,3-trifluoropropyl groups were introduced to enhance the latter. Synthesis of a specifically carboranesilanol-terminated polymer allowed preparation of ultra-high molecular weight polymer M > 1 million and alternating block copolymers; however, its synthesis proved difficult to reproduce for unidentified reasons. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1978
- Accession Number
- ADA059057
Entities
People
- C. D. Beard
- E. Hedaya
- G. B. Dunks
- J. J. Bohan
- K. A. Barker