Accession Number:

ADA169252

Title:

The Control of Polymer Mechanical Behavior by Surface Modification.

Descriptive Note:

Final rept. 1 May 79-4 Jul 85,

Corporate Author:

ILLINOIS INST OF TECH CHICAGO

Personal Author(s):

Report Date:

1986-05-15

Pagination or Media Count:

10.0

Abstract:

The effect of a brittle surface layer on the mechanical behavior of polymers has been studied. The brittle surface layer has been simulated by laminating a thin film to a polymer or by ultra violet irradiation of the surface. Fracture mechanics theories have been utilized to account for the phenomenon of surface embrittlement. A criterion has been established suggesting that embrittlement will only occur when the dynamic stress intensity factor in the brittle layer reaches a value greater than the arrest toughness of the ductile substrate. It has also been shown that the embrittlement phenomenon can be described in terms of a critical crack velocity or critical thickness. It is shown that brittle films less than .005 inches thick can cause brittle failure of polymers such as polycarbonate and ABS. It is also shown that cracks can attain velocities of up to 200 msec when propagating through such films. Keywords FractureMechanics.

Subject Categories:

  • Plastics
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE