High-Performance Polymeric Materials.

A variety of theoretical methods were used to elucidate the structure and properties of rigid rodlike polymer chains which are of interest as high-performance polymeric materials. Semi-empirical molecular mechanics methods were used to calculate the intramolecular and intermolecular energies pertinent to conformational flexibility and chain packing effects. Also, geometry optimized CNDO2 molecular orbital calculations were carried out to investigate the structure and conformational characteristics of the rodlike polymers, in both the unprotonated and protonated states. Electronic band gap calculations within the extended Huckel approximation were carried out to elucidate the packing and electronic properties of these chains in the crystalline state. Keywords Rodlike polymers, Aromatic heterocyclic polymers, Conformational energies, Intermolecular interactions, Polybenzobisoxazoles, Polybenzobisthiazoles, Chain flexibility, Chain packing, Electrical conductivity, Ceramic particles, Elastomer reinforcement.