The versatile cross-linking chemistry of poly(dimethylsiloxane) (PDMS) based materials affords a large research space in which polymers with widely varying elastomeric properties can be synthesized. Parameters such as PDMS chain length, cross-link density, cross-link functionality, filler content, and PDMS chain chemistry can all be modified to produce materials with specific physical and mechanical properties. These elastomers are generally intractable, which makes the precise characterization of these networks problematic. While advancements in analytical techniques have enabled improved insight into the network structure of model PDMS systems, substantial gaps in the fundamental understating of structure-property relationships persist. We report the application <sup>1</sup>H DQ NMR spectroscopy to determine the network topology of a series of mono-modal and bimodal, model PDMS networks. Analysis of elastomers swollen in deuterated toluene exposes complex network structure even within mono-modal samples that is not revealed through more traditional characterization techniques. This data, combined with solvent uptake and mechanical analysis, provides an in-depth description of the network level structural motifs that govern the macroscopic material properties of siloxanes.

Characterization of network structural motifs in siloxane elastomers using magnetic resonance

254th National Meeting (2017)

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