Hygrothermal stability of polyimide resins and composites

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:237762

Thorp, K E.G.; Crasto, A S ^[1]

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1. Univ. of Dayton Research Inst., OH (United States)

Moisture absorption in most fiber-reinforced polymer composites is associated with a decline in the glass transition temperature (Tg) which may be attributed to plasticization of the matrix. This phenomenon is reversible, with the material showing a recovery of the original Tg on drying. High-temperature polyimide composites also display a marked drop in Tg in a hygrothermal environment; however, this decline increases with increasing hygrothermal exposure, and the Tg is not recovered on drying. A number of material factors appear to influence the magnitude of this Tg drop including composite moisture diffusivity, resin matrix chemistry and initial matrix properties, which govern the rate of moisture transport and its (chemical or physical) interaction with the matrix. The influence of each of these factors must be investigated to provide insight into the origin of this phenomenon which is required to design polyimide systems with improved resistance to hygrothermal degradation. In this study the diffusion characteristics of neat polyimide resins and composites are investigated and correlations sought with initial material properties as well as resistance to hygrothermal degradation. The resulting data provide some insight into the origin of this phenomenon and suggestions for practical limitations on the use of these materials in hygrothermal environments.

• OSTI ID: 237762
• Report Number(s): CONF-9510177--; ISBN 1-56676-376-2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
CARBON FIBERS
COMPOSITE MATERIALS
DIFFUSION
EPOXIDES
EXPERIMENTAL DATA
HYDRATION
IMIDES
KINETICS
ORGANIC POLYMERS
SAMPLE PREPARATION
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
TRANSITION TEMPERATURE
WATER
WEIGHT MEASUREMENT