Solid-state NMR investigation of the structural consequences of plastic deformation in polycarbonate. 2. Local orientational order

The effects of plastic deformation on conformation and local packing in pol ycarbonate have been quantified using polarization-transfer and double-quan tum NMR methods. To within experimental precision, the conformational distr ibution was found to be unaffected by the deformation, whereas small change s in the local packing of molecular segments could be detected. The phenyle ne ring planes exhibit a tendency of orienting parallel to one another upon deformation, and the pair correlation functions between the molecular segm ents under study increase in amplitude at short separations. The experiment al results are compared to athermal atomistic simulations, and their implic ations with respect to proposed heuristic models of the process of plastic deformation in polymer glasses are discussed.