Accession Number : AD0845077

Title :   Analytical Methods for Determining the Shrinkage Stresses in Polymeric Materials During Cure.

Descriptive Note : Technical rept.,

Corporate Author : ROHM AND HAAS CO HUNTSVILLE AL REDSTONE RESEARCH LABS

Personal Author(s) : Cost, Thomas L.

Report Date : DEC 1968

Pagination or Media Count : 65

Abstract : An exploratory study was performed to determine the problems associated with predicting the stresses and strains in viscoelastic materials polymerizing in geometric shapes typical of solid propellant rocket motor grains. Two approximate methods were developed for determining the stresses and strains in polymerizing bodies provided the dependence of the material properties on degree of cure can be established. One method is restricted to isothermal conditions, while the second method is restricted to steady-state thermal conditions. The methods are illustrated by application to example problems in which isothermal, uniform temperature conditions are assumed. A theory proposed by Bueche which relates the mechanical response of a fully cured polymer to its molecular structure is described in detail. To relate the mechanical properties of a polymeric material to the degree of cure, Bueche's theory is modified by making the molecular structure parameters in the theory dependent on degree of cure. Several experimental techniques for determining the relation of the mechanical properties to degree of cure are described. (Author)

Descriptors :   (*SOLID ROCKET PROPELLANTS, AGING(MATERIALS)), VISCOELASTICITY, POLYMERS, SOLID ROCKET PROPELLANT PLASTICIZERS, VOLUME, SHRINKAGE, DENSITY, DEFECTS(MATERIALS), ROCKET PROPELLANT GRAINS, MICROSTRUCTURE, RHEOLOGY, VISCOSITY, MATHEMATICAL MODELS, MOLECULAR WEIGHT, ACRYLIC RESINS.

Subject Categories : Mechanics
      Solid Rocket Propellants

Distribution Statement : APPROVED FOR PUBLIC RELEASE