A comparison of the 13C nmr spectra of eight cinchona alkaloids in CDCls and in DMSO-d6 has pointed out some important chemical shift differences which should be useful in the identification of similar compounds. The 13C chemical shifts of carbons 2 and 6 of the quinuclidine ring can be used to distinguish between quinine and quinidine derivatives. Similarly, 13C chemical shifts of C-4' should provide a means of distinguishing between three and erythro compounds (quinine and 9-epiquinine derivatives). Solvent studies on these compounds show that intramolecular hydrogen bonding has a large effect on the 13C chemical shifts of the carbons 6, 7, and 4', indicating that 13C nmr will be a useful tool to study important conformational problems of these and related compounds.

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The bulk mechanical properties of a blend of elastomers are found to depend on the micro and nano scale morphology of the phases of the materials in the blend. In this study, we examine the phase morphology of blends of incompatible elastomers using Atomic Force Microscopy (AFM). Specifically, nanoindentation and Tapping Mode AFM (TMAFM) imaging techniques are used as experimental tools for mapping the composition of unfilled elastomeric blends. Depending on the composition of the blend, either co-continuous or discontinuous domain/matrix morphology is observed. To identify the different components in bromobutyl (BIIR)/natural rubber (NR) blends, nanoscale indentation measurements were made on the observed phaseseparated regions. Results from force mode AFM and mechanical measurements of bulk NR and BIIR are used to assist in the interpretation of the TMAFM results for the BIIR/NR blends. V V C 2005 Wiley Periodicals, Inc.* J Polym Sci Part B: Polym Phys 44: 492-503, 2006

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