ABSTRACT
In polymer matrix composites (PMCs), the region separating the bulk polymer from the fibrous reinforcement is of utmost importance to load transfer. This region was originally dubbed an interface, but is now most often viewed to be an interphase because of its three-dimensional, heterogeneous nature [1, 2]. This is not to say that it is a distinct phase, as the interphase does not have a clear boundary. It is more accurately viewed as a transition region that possesses neither the properties of the fiber nor those of the matrix. Consequently, the mechanical properties of the interphase are of interest. This paper discusses methods used in these analyses and a new approach to measuring the size and relative mechanical properties of the interphase.
