Analytical Methods for Determining the Shrinkage Stresses in Polymeric Materials During Cure.
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1968
- Accession Number
- AD0845077
Entities
People
- Thomas L. Cost