Thickness Effects on Material Properties in a Glass/Thermoplastic P.E.T. Injection Molding Compound,

Abstract

Rynite 545, a commercial short glass fiber/ thermoplastic polyethylene terepthalate system, was injection molded into end-gated rectangular plaques of various thicknesses. The plaques were sectioned and characterized by scanning electron microscopy and by mechanical and thermal expansion tests. The glass fibers are shown to be highly aligned in 'boundary layers' near the mold surfaces, and are distributed more randomly away from the mold surfaces. As part thickness increased, the aligned fiber boundary layers occupied a smaller proportion of the cross section, resulting in a decrease in mechanical properties. Tensile moduli are derived for boundary and center layers, which can be used to accurately predict the effective moduli at different thicknesses. In addition, the boundary layer thicknesses at the top and bottom surfaces were unequal, producing noticeable warping for thicker plaques. (MM)

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1980
Accession Number
ADA303085

Entities

People

  • R. B. Pipes
  • Robert C. Wetherhold
  • William A. Dick

Organizations

  • University of Delaware

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Asymmetry
  • Boundary Layer
  • Composite Materials
  • Electron Microscopy
  • Injection Molding
  • Materials
  • Materials Processing
  • Materials Science
  • Mechanical Properties
  • Moldings
  • Orientation (Direction)
  • Plastics
  • Reinforced Plastics
  • Scanning Electron Microscopy
  • Tensile Modulus
  • Thermal Expansion
  • Thermal Stresses

Fields of Study

  • Materials science

Readers

  • Fluid Mechanics and Fluid Dynamics.
  • Mathematics or Statistics
  • Polymer Science and Engineering.

Technology Areas

  • Microelectronics
  • Microelectronics - Graphene