A reactive sizing
was designed to achieve high levels of interfacial
adhesion and improved mechanical properties with a carbon fiber–acrylate
system cured by electron beam (EB). The sizing was made of a partially
cured epoxy sizing with a high density of pendant functional groups
(acrylate functionality) to facilitate covalent bonding with the matrix.
The interlaminar shear strength improved from 61 to 81 MPa (+33%)
without postprocessing, reaching a shear strength similar to that
of the same system cured by a thermal treatment. Observation of the
fracture profiles clearly highlighted a change in the fracture mechanism
from a purely adhesive failure to a cohesive failure. To the best
of our knowledge, such improvements of the mechanical properties of
carbon fiber composites cured by EB, without any postcure, have not
been reported previously. This constitutes a breakthrough for the
industrial development of EB curing of composites.