AbstractThe high degree of flexibility of blends containing minor amounts of partly crystalline copolymers of ethylene and vinyl acetate in paraffin wax seems to be a manifestation of some type of interaction. Low‐angle x‐ray diffraction of such blends showed a new long spacing intermediate in length between the polymer long spacing and thecaxis length of the wax unit cell. This new long spacing appears to be a consequence of isomorphism involving cocrystallization of polymeric ethylene sequences and wax molecules. A lesser type of isomorphic interaction, epitaxy, occurs in polyethylene–wax blends: wax overgrows crystals of already crystallized polyethylene in the same orientation without a change in itscaxial dime