Catalytic hydrogen-deuterium exchange provides a facile method for labeling commercially available polyolefins. Labeling with deuterium creates isotopic contrast, which is needed for neutron scattering experiments. While many model polymers used for neutron scattering are monodisperse and have uniform microstructures, commercial polyolefins are often composed of a broad range of molecular weights with varying amounts of comonomer distributed heterogeneously among them. Exchange reactions performed on such complex resins may result in correspondingly nonuniform distributions of deuterium. Understanding the relative scattering contribution from different populations of chains can be essential to interpretation of neutron scattering results. Here, we describe a method that allows for semi-quantitative measurement of the concentration of deuterium across the molecular weight distribution of the sample using high temperature size exclusion chromatography with infrared detection. The method also provides qualitative information about the relative enrichment of comonomers at a particular molecular weight.

Characterization of the distribution of deuterium as a function of molecular weight in D-labeled commercial polyolefins

249th National Meeting (2015)

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