DTIC AD0484094: THERMAL EXPANSION OF REINFORCED COMPOSITES pdf

DTIC AD0484094: THERMAL EXPANSION OF REINFORCED COMPOSITES

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The effects of thermal cycling and variable thermal history on the dimensional behavior of reinforced plastic composites are presented. Thermal expansion was used as the primary independent variable in studying the wide variations in composite dimensions with thermal treatment, collectively termed thermal hysteresis phenomenon. The composites studied were those currently considered in structural and ablative applications. It has been found that the thermal expansion characteristics of a given composite may vary by more than 100% in cycling between room temperature and about 400 F. The most striking phenomenona which is consistently observed is a decrease in the expansion coefficient to zero about 200 F followed by an increase at higher temperatures. Studies completed in analyzing this behavior included the following: (1) internal stress behavior of the composite as reflected in tensile and flexural modulus characteristics, (2) second order transitions of the polymeric matrix, (3) moisture absorption in the matrix, and (4) thermogravimetric analysis of the matrix and composite.

Correlations between analytical model predictions and experimental performance were made on the various composites studied. Extensions of these models in explaining and estimating the dimensional behavior of other composite materials are discussed

• Creator/s: Defense Technical Information Center
• Date: 3/1/1966
• Year: 1966
• Book Topics/Themes: DTIC Archive, Denman, G L, AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OH, *PLASTICS, *REINFORCING MATERIALS, ELASTIC PROPERTIES, GRAPHITE, MODEL TESTS, THERMAL EXPANSION, WEIGHT, MOISTURE, TEXTILES, EPOXY RESINS, SORPTION, HYSTERESIS, HUMIDITY, PHENOLIC PLASTICS, THERMOGRAVIMETRIC ANALYSIS, GLASS TEXTILES, DENSITY, COMPOSITE MATERIALS

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