GEOMETRIC AND ELECTRONIC-STRUCTURE OF ALKANE BENZENE, ETHYLBENZENE/BENZENE, AND ALKANE/ETHYLBENZENE COMPLEXES - TOWARDS THE CHARACTERIZATION OF POLYMER ALLOY COMPOSITES/

As a first step towards the theoretical investigation of polymer alloy composites formed by the dispersion of carbon black particles through out a polyethylene/polystyrene blend, we discuss here the results of a b initio Hartree-Fock quantum-chemical calculations, including correla tion effects via second-order Moller-Plesset perturbation theory, on s mall model systems. These are chosen to simulate the various interface s that appear in the composites: the interfaces between the polymers a nd the graphitic surface of carbon black are modeled by the complexes formed by benzene (taken as the substrate) with methane, ethane, propa ne, and ethylbenzene while the polymer/polymer interface is modeled by the propane/ethylbenzene system. The functionalization of the benzene substrate with hydroxyl, amine, carboxylic, or quinoid groups is also investigated in order to determine the influence of such moieties tha t can be present on the carbon surface. Our main goal by studying thes e model systems is to characterize the primary binding interaction sit es and to evaluate the energies involved in the bonding; our results c an also serve as a reference for molecular mechanics calculations on m ore extended systems. (C) 1998 Elsevier Science S.A. All rights reserv ed.