The fractal approach and the effect of nanoadhesive in polymer nanocomposites

Abstract

Currently, a thermodynamic fractal model of the formation of an interphase layer in polymer nanocomposites is becoming widespread. In accordance with this model, the surface of nanoparticles with which the polymer matrix interacts is a fractal object. This means that the number of contact points depends on the dimension of the nanoparticle surface accessible for such a contact (unshielded). The dependences of the interfacial adhesion parameter on the coefficients of thermal expansion, nanoparticle size, fractal dimension of the nanoparticle surface, etc. have been obtained. In polymer nanocomposites, the level of interfacial adhesion, in comparison with microcomposites, is an order of magnitude higher. This phenomenon is called the nanoadhesion effect and it has an absolutely dimensional character, i.e. takes place when polymers are filled with nanosized particles. Currently, to assess the level of interaction between the phases “nanoparticle-polymer” use the parameter of the level of interfacial adhesion, which is calculated by the values of three quantities: the actual coefficient of linear thermal expansion of the investigated nanocomposite, the coefficients of linear thermal expansion, calculated by the rule of mixtures and by the Turner formula. Considering a nanoparticle as a fractal object, it is possible to estimate the influence of the nanoparticle size, fractal dimension of the nanoparticle surface, and the volumetric content of the filler on the level of interfacial adhesion in the nanocomposite. The article investigates the influence of the size of nanoparticles and the fractal dimension of the surface of aluminum nanoparticles on the parameter of interfacial adhesion. It has been established that filling the polymer matrix with aluminum nanoparticles with the size rn = 35nm, fractal dimension of the nanoparticle ds = 3,3 surface will provide the effect of nanoadhesion in the new nanocomposite based on the elastomer. Experimental studies have confirmed the presence of the nanoadhesion effect in the nanocomposite based on the F-40C elastomer, which manifested itself in an increase in its deformation and strength properties. The optimal composition of the nanocomposite, which provides the highest deformation and strength properties of the material, has been determined.