Accession Number:

AD0736859

Title:

Crack Propagation Studies in Glassy Polymers

Descriptive Note:

Final rept. 16 Jun 1969-15 Oct 1970

Corporate Author:

ILLINOIS INST OF TECH CHICAGO

Report Date:

1971-09-01

Pagination or Media Count:

284.0

Abstract:

The object of this study was to determine the influence of crack velocity on the fracture surface work of glassy polymers. PMMA and polystyrene were studied and it was hypothesized that the fracture surface work as a function of crack velocity could be explained by molecular relaxation behavior. Activation energies were determined for the fracture process of various temperatures and crack velocities. The fracture surface work of rubber modified acrylics has been studied as a function of crack velocity and rubber concentration. The fracture surface work is greatly dependent upon both rubber concentration and crack velocity and more than one maximum in the curve of fracture surface work versus crack velocity can occur depending upon the rubber concentration. A METHOD OF CRYSTALLIZING THICK POLYCARBONATE SHEETS BY ACETONE VAPOR WAS DEVELOPED. The mechanical properties of these sheets were studied as a function of residual acetone content. Cold rolling of these sheets as well as amorphous thermoplastics was accomplished and the impact strength can be greatly increased by cold rolling. A MICROMECHANICS ANALYSIS USING FINITE ELEMENT METHODS WAS PERFORMED ON RUBBER MODIFIED POLYMERS AND THE INTERNAL STRESSES WERE CALCULATED AS WELL AS THE MODULUS OF ELASTICITY AND CRITICAL STRESS FOR STRESS WHITENING AS A FUNCTION OF RUBBER CONCENTRATION.

Subject Categories:

  • Laminates and Composite Materials

Distribution Statement:

APPROVED FOR PUBLIC RELEASE