Adhesion between carbon fibers and cationic matrices in electron beam processed composites

摘要

The electron beam initiated polymerization of a representative epoxy based formulation for fiber-reinforced composites has been investigated by infrared spectroscopy and thermo-mechanical analysis; and the adhesion between fibers and matrix has been measured with the microindentation test method. Many factors seem to be responsible for the lower adhesion in electron beam processed materials compared to thermally processed composites. First of all, chemical bond between carbon fiber and amine-cured epoxy resin used In conventional composites are not effective in the cationic electron beam initiated polymerization, due to a strong inhibition of the cationic curing by the primary and secondary amines. Furthermore, fast curing at low temperature is a significant advantage of electron beam processing, but it may be detrimental to the stress relaxation and to the mechanical bonding between fibers and matrix. The relationships between electron beam processing conditions (dose, dose per pass, temperature profile), the resulting matrix properties and the adhesion of the epoxy matrix to carbon fibers are examined. The adsorption of the matrix on the fibers has also been quantified. Finally, this study illuminates the relationship between matrix properties and adhesion properties in the composite material.