Mechanical properties and environmental effects of epoxy resins in the neat state and in composites

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5567792

Yang, C M.P.

The dynamic mechanical properties of graphite fiber reinforced, epoxy matrix composite laminates subjected to loading perpendicular to the plane of lamination and of neat epoxy resin are reported. The centrosymmetric deformation (CSD) test geometry provides an accurate and convenient test mode for the study of the viscoelastic behavior of very stiff graphite-epoxy laminates. It is found that the in-phase and out-of-phase stiffness superpose to form master curves covering a frequency range of 12 decades. By a suitable scaling procedure of the master curves, it is found that the in-phase stiffness has the same shape and the out-of-phase has the same dispersion for all laminates irrespective of the stacking sequence. The dispersion characteristics of in-situ and neat resin epoxy were nearly identical, but with the neat resin having a lower glass-transition temperature. The graphite/epoxy composites and neat resin epoxy have been shown to be sensitive to hygrothermal environment. For postcured specimens the plasticization and inhomogeneous swelling effects due to the moisture absorbed are found to be reversible, in the sense that the initially dry properties of the laminate are recovered after redrying the wet specimen. On the other hand, for as cured specimens, the plasticization and inhomogeneous swelling effects are found to be irreversible under the same hygrothermal environment.

• Research Organization: Rensselaer Polytechnic Inst., Troy, NY (USA)
• OSTI ID: 5567792
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360301 -- Composite Materials-- Preparation & Fabrication-- (-1987)
360303* -- Composite Materials-- Mechanical Properties-- (-1987)
CARBON FIBERS
COMPOSITE MATERIALS
CURING
EPOXIDES
FIBERS
MATERIALS
MECHANICAL PROPERTIES
MOISTURE
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
POLYMERS
RESINS