The Control of Polymer Mechanical Behavior by Surface Modification.

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 m/sec when propagating through such films. Keywords: Fracture(Mechanics).

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Document Details

Document Type
Technical Report
Publication Date
May 15, 1986
Accession Number
ADA169252

Entities

People

  • Lawrence J. Broutman

Organizations

  • Illinois Institute of Technology

Tags

Communities of Interest

  • Human Systems

DTIC Thesaurus Topics

  • Coatings
  • Crack Tips
  • Cracks
  • Elongation
  • Engineering
  • Engineers
  • Films
  • Fracture (Mechanics)
  • Materials
  • Materials Engineering
  • Mechanics
  • Molecular Weight
  • Stress Concentration
  • Stress Intensity Factors
  • Stress Strain Relations
  • Stresses
  • Thin Films

Readers

  • Materials Science (Mechanical Engineering).
  • Polymer Science and Engineering.
  • Thin Film Deposition Science.