Characterization of the glass Transition Using a Microindenter.

Abstract

The microindenter described here requires a very small sample (c. 10 mg), can be used with heating rates comparable to those in DSC (ie., 10 C/ minute), and gives a large, clearly defined change at the glass transition. The essential features are a needle probe and a linear variable differential transformer (LVDT). By suitably controlling the force on the needle, the rate of heating, and the sample thickness, reproducible results can be obtained. The small sample size permits a relatively fast heating rate. Most mechanical tests (often using oscillating stress and strain) require large samples with a corresponding long time for temperature equilibration to take place (ASTM D 4065). Another indentation test, the Vicat Softening Temperature (ASTM 1525) also uses a thick (3 mm) sample. Like the Vicat test, the present procedure is best suited to amorphous polymers. The application to plasticized samples of poly(methyl methacrylate) illustrates the utility of the method.

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Document Details

Document Type
Technical Report
Publication Date
Feb 22, 1991
Accession Number
ADA232154

Entities

People

  • Ferdinand Rodriguez
  • Treva Long

Organizations

  • Cornell University School of Chemical and Biomolecular Engineering

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Alkenes
  • Chemical Engineering
  • Chemical Synthesis
  • Chemistry
  • Classification
  • Engineering
  • Ethylenes
  • Films
  • Heat Transfer
  • Materials
  • Methacrylates
  • Military Research
  • Polymeric Films
  • Polymers
  • Security
  • Thermal Conductivity
  • Transition Temperature

Fields of Study

  • Materials science

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Systems Analysis and Design
  • Thermal Physics or Thermal Science.