Accession Number : ADA302560

Title :   Formulation/Cure Technology for Ultra-High Molecular Weight Silphenylene-Siloxane Polymers.

Descriptive Note : Technical paper,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER

Personal Author(s) : Huindley, N. H. ; Patterson, W. J.

PDF Url : ADA302560

Report Date : MAY 1985

Pagination or Media Count : 22

Abstract : Molecular weights above one million were achieved for methylvinylsilphenylene-siloxane terpolymers using a two-stage polymerization technique which was successfully scaled up to 200 grams. The resulting polymer was vulcanized by two different formulations and compared to an identically formulated commercial methylvinyl silicone on the basis of ultimate strength, Young's modulus, percent elongation at failure, and tear strength. Relative thermal/oxidative stabilities of the elastomers were assessed by gradient and isothermal thermogravimetric analyses performed in both air and nitrogen. The experimental elastomer exhibited enhanced thermal/oxidative stability and possessed equivalent or superior mechanical properties. The effect of variations in prepolymer molecular weight on mechanical properties was also investigated.

Descriptors :   *POLYMERIZATION, *MOLECULAR WEIGHT, *SILOXANES, *CURING, MECHANICAL PROPERTIES, METHYL RADICALS, MODULUS OF ELASTICITY, ELASTOMERS, FAILURE, THERMAL STABILITY, STRENGTH(MECHANICS), NITROGEN, OXIDATION, ELONGATION, ISOTHERMS, VINYL RADICALS, FORMULATIONS(CHEMISTRY), TEARING, THERMOGRAVIMETRIC ANALYSIS, VULCANIZATION.

Subject Categories : Polymer Chemistry
      Inorganic Chemistry
      Organic Chemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE