AVS 47th International Symposium
    Material Characterization Thursday Sessions
       Session MC-ThM

Paper MC-ThM10
Nano-Mechanics of Polymer Surfaces

Thursday, October 5, 2000, 11:20 am, Room 207

Session: Polymer Characterization
Presenter: R.M. Winter, South Dakota School of Mines and Technology
Authors: C. Steffan, South Dakota School of Mines and Technology
H. Liu, South Dakota School of Mines and Technology
R.M. Winter, South Dakota School of Mines and Technology
Correspondent: Click to Email
We report on the nano-mechanical properties (elastic modulus and time dependent phenomena) of polymer surfaces as they relate to polymer matrix composites. This work is prompted by the desire to engineer macroscopic polymer matrix composite properties by systematic variation of nano- and micro-scopic properties of the interphase. The interfacial force microscope, a scanning probe microscope, which utilizes a non-compliant force sensor is employed to characterize the surfaces. Force-displacement curves are obtained, from which, elastic modulus is determined using contact mechanics analysis. Creep and relaxation experiments are performed to characterize the time dependent phenomena of the polymeric surfaces. The surfaces are comprised of epoxy, amine curing agent, and amine coupling agent of systematically varied epoxy-amine equivalence ratios. These ideal interphases model the interphase found in polymer matrix-inorganic reinforcement composites and are used to reveal the relationship between chemistry and nano-mechanical properties. Fourier transform infrared spectroscopy is used to analyze the model interphase chemical composition as a function of amine-epoxy equivalence ratio. The FT-IR analysis and nano-mechanical results are correlated showing how elastic modulus and time dependent properties can be controlled by varying the chemistry and reaction conditions of the system. These data are compared to previously obtained elastic modulus profiles of the interphase in fiber reinforced epoxy matrix composites where the modulus was found to vary by 100% in a ~5 micron region surrounding the reinforcing fibers.