Relaxation Studies on Glassy Polymers

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Studies are conducted on the dynamics and relaxation behavior of glassy polymers. Experimentally, the methods of modern high-resolution NMR of solids will be used in conjunction with a recently developed dilatometry technique as a probe of the molecular motions and chain-packing effects in glassy polymers. In particular, the investigator will perform so-called CPMAS NMR experiments on polycarbonates under high carbon dioxide pressure to obtain information on the effects of absorbed gas molecules on the molecular motions and chain packing. The investigator will also use multiple quantum NMR to obtain new information about the extent of correlated motion of the polymer in the glass and to correlate the NMR experiments with macroscopic properties, e.g. dynamic mechanical loss. Theoretically, the investigator will use a combination of computer simulations, phenomenological model building, and statistical mechanics to understand the relaxation processes in glassy polymers.