Preparation and Evaluation of Exactly Alternating Silarylene-Siloxane Elastomers.
Abstract
Four monomers needed for the preparation of exactly alternating silarylene-siloxane polymers of high molecular weight were prepared in high purity. The polymerization reaction based on the combination of a disilanol monomer (either the p-phenylene or the p,p1 -diphenyl ether) with a diureidosilane monomer (either the dimethyl or the methylvinyl) was applied successfully to the preparation of polymers and copolymers having weight average molecular weights greater than 100,000. A particularly important problem in these preparations was the stability of the ureidosilane monomer. The glass temperatures of the two dimethylsiloxane-diol homopolymers as determined by DSC were -64 and -24 C for the p-phenylene and the p,p -diphenyl ether polymers, respectively. The thermal stabilities of these homopolymers and copolymers as determined by TGA were fairly simple in behavior in nitrogen but quite complex in air. Incorporation of the methylvinylsiloxane units into the exactly alternating copolymers resulted in considerable increases in thermal stability. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1978
- Accession Number
- ADA058890
Entities
People
- Petar R. Dvornic
- Robert W. Lenz
Organizations
- University of Massachusetts Amherst