COMPOSITE INTERPHASE CHARACTERIZATION

This paper review techniques which are used for characterization of interphase surfaces on fiber-reinforced platics composites. They include - (1) surface spectroscopies - atomic and molecular information about the reinforcement surface; (2) thermal desorption - identification and quantification of the species able to volatilize at the interphase during fabrication; (3) surface energetics - thermodynamic quantities necessary to predict the wettability of the reinforcement surface and the interaction with the matrix; (4) interfacial shear strength - mechanical response of the interphase to environment; and (5) microtomy and microscopy - determination of the locus of failure in the interphase region. Proper combination of these techniques is necessary to provide a true picture of the interphase. Two different graphite fiber-epoxy interphases are characterized to illustrate the complexity of this region and the mechanisms by which the interphase affects fiber-matrix interfacial shear strength.