Ab initio studies on modulus of elasticity of modified polycarbonates

Young’s moduli of modified polycarbonates were studied by ab initio methods. The structure of the polymer chain was modified by (1) replacing the backbone carbon atom with oxygen or sulphur atom (2) changing the substituents at the backbone carbon atom, and (3) introducing substituents at the phenyl rings. The study included nine experimentally characterized and four hypothetical polymers. Young’s modulus was increased when the backbone carbon was replaced with oxygen, and when electron donating groups were introduced at phenyl rings. The highest modulus was obtained when strongly electron donating NMe2 groups were substituted at the backbone carbon atom. The molecular modelling results were in agreement with experimental data.