THE STRENGTH OF NANOCOMPOSITES POLYMER / 2D-NANOFILLER WITH ULTRASMALL FILLER CONTENTS

Abstract

The theoretical model, using the notions of fractal analysis is proposed for description of strength of nanocomposites polymer/2D-nanofiller on the example of nanocomposites polyvinylalcohol/boron nitride. For correct description of strength of these two-phase nanomaterial the knowledge of initial characteristics of matrix polymer (stress of fracture), geometrical parameters of nanofiller and level of interfacial adhesion polymer matrix-nanofiller is necessary. The indicated level, characterizing by shear interfacial strength, was determined theoretically within the framework of fractal conception of adhesion. Its absolute values found high enough – they are comparable with this characteristic in systems polymer-carbon nanotubes and are higher essentially than in systems polymer-microfiber (glassy and carbon fibers). This factor defines high enough strength of the considered nanocomposites. The important factor for fracture process of nanomaterials is aggregation of initial platelets of nanofiller, which forms “packets” (tactoids) of such platelets. The relatively small aggregation degree of nanofiller gives appreciable reduction of strength of nanocomposites polymer/2D-nanofiller. The indicated reduction is connected with transition of 2D-nanofiller structure from exfoliated to intercalated one, i.e. from separate platelets to their tactoids.