Compressive creep of IM7/K3B composite and the effects of physical aging on viscoelastic behavior
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Abstract
An experimental study was undertaken to establish the viscoelastic behavior of IM7/K3B composite in compression at elevated temperature. Creep compliance, strain recovery and the effects of physical aging on the time dependent response was measured for uniaxial loading at several isothermal conditions below the glass transition temperature (T g ). The IM7/K3B composite is a graphitereinforced thermoplastic polyimide with aT g of approximately 240°C. In a composite, the two matrix-dominated compliance terms associated with time dependent behavior occur in the transverse and shear directions. Linear viscoelasticity was used to characterize the creep/recovery behavior, and superposition techniques were used to establish the physical aging related material constants. Creep strain was converted to compliance and measured as a function of test time and aging time. Results included creep compliance master curves, physical aging shift factors and shift rates. The description of the unique experimental techniques required for compressive testing is also given.
Keywords
Glass Transition Temperature Polyimide Creep Strain Viscoelastic Behavior Physical AgingPreview
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