Multiscale modeling of polymer composite properties

Polymer composites are heterogeneous viscoelastic media. The ascertainment Of the quantitative relations between the microstructure and macromechanical properties of these materials is a very important scientific problem. Some distinctive computer technologies, which lead to multiscale computational experiments: and investigations of peculiarities of micromechanical behavior of heterogeneous composite media taking into consideration atomic-molecular formations, have been discussed. These approximations are important elements in the nanotechnological problem of construction Of new perspective materials. We consider the results of calculation by the Monte Carlo approach as a perspective method for the description of the important features of atomic and molecular texture and energetics of heterogeneous polymer media, namely, different flexible-chain molecules and nanoclusters of technical carbon chemically terminated with different substances. The representative element of this structure keeps up to 1.5 x 10(6) atoms. The parallel technologies of calculations and supercomputers have been used. Estimation of structural peculiarities and energies of interaction of systems consisted of polymeric macromolecules and nanoparticles of fillers, variation of superficial chemical properties of fillers, and evaluation of water presence inside the media, all of which are ideated as highly useful for the understanding of the macromechanics of composites. The quantum-mechanical approach is discussed as the method for solution of the foremost problems of micromechanics of reinforced polymer (rubber) composites, namely, W an investigation of the interaction of soot model particles with nonterminated and H-terminated surfaces, with segments of polymer chain with different chemical structures, and consideration of the impact of a chemical nature of the polymer and chemical nature of surface soot modification on the enthalpy of binding and the force of micromolecular shifting (friction); (ii) an investigation of the interaction of soot particles without an interface layer between them., and evaluation of the influence of chemical modification of the soot surface on the binding enthalpy and the shifting force of these particles (nonterminated and terminated by H, OH, and COO surface groups); and (iii) an investigation of the interaction of soot particles with an interparticle layer of polymer and water between soot particles, and evaluation of the chemical nature of the particles that are adsorbed at the interface of soot particles on their binding enthalpy and force Of microscopic friction (nonterminated and terminated by H soot surfaces). Calculations were done in a parallel mode using supercomputer MVC-1000M (Moscow). Optimization of the viscoelastic behavior of composite media such as rubbers leads to the procedure of identification. Validity of the effect of reinforcement on the basis of the analysis of relaxation properties of materials seems very promising.