PCILO and CNDO calculations on the specific interaction in two model analogs of BPA‐polycarbonate and a linear aliphatic polyster

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AbstractPrevious investigations have given evidence of the existence of specific chemical interactions between poly(bisphenol‐A carbonate) (PC) and a number of linear aliphatic polyesters, with the consequent formation of compatible polymer alloys. Here we address the particular kind of specific interaction that takes place in these systems by performing a quantum‐mechanical study of the apparently most reasonable types of molecular interactions occurring in model compounds of the above polymers. Complete neglect of diffential overlap, (CNDO), in its CNDMEX version, and perturbative configuration using localized orbitals (PCILO) were the calculation schemes used on diphenyl carbonate (DPC) and dimethyl succinate (DMS), selected as models. It was found that, on a one‐to‐one basis, the DPC‐DMS system is energetically more stable than the individual separate molecules; on examination of the possible interaction sites for the two chemical species, the interaction between the ester group oxygen in one DMS molecule with one of the phenyl rings in DPC appears to be the most favorable type of molecular interrelation, even though hydrogen bond formation is also possible between the oxygen atoms in DPC and the methylene hydrogens in DMS. (The former interaction decreases the total energy of the system by 0.12 kcal/mol, more than the latter.)