INTRODUCTION
Substantial progress in understanding of the phenomena taking place at the interphase in composite polymeric materials has been made lately.1,2 The production industry of polymeric composite materials, i.e. polymers with dispersed mineral fillers and reinforced plastics with organic and inorganic fibers is nowadays very highly developed. Advent of the new types of reinforcing fibers—carbon, boron, high-modulus and heat-stable synthetic fibers—along with successes of chemistry in the development of new resins has made possible the solution of a number of important technical problems. However, as a rule, these solutions are not based on clearly established mechanisms of the processes taking place at the interphase between the two components, although these phenomena determine the most important physical and mechanical properties of the compositions, and although the interphase is the region whose properties in large measure control the properties of the material. Despite a great number of works in this field there still exist many unsolved problems. Discussion of some of them is the subject of the present paper.