Anelastic Deformation of a Thermoplastic-Matrix Fiber Composite at Elevated Temperature;Part I: Neat Resin Structure Characterization

Abstract

This is part of a series of articles on the properties of a thermoplastic polyamide matrix [PACM-12, DuPont, poly(bis-4-4'-dicyclohexylmethane) n-dodecane diamide]/graphite fiber (AS4, Hercules) composite. The structural characterization of the neat resin by differential scanning calorimetry (DSC) and X-ray diffraction as a function of processing history is described here. PACM-12, considered a representative ther moplastic matrix polymer for advanced composites, as well as an engineering plastic, is partially crystalline (ca. 20%) under normal composite processing conditions, but can be quenched to a completely amorphous state. The complex DSC results are shown to result, at least in part, from the presence of a different crystal structure in slow cooled PACM-12 than in quenched, annealed or fiber samples, to a melting-recrystallization-melting pro cess during heating and to the effect of heating rate.