Quantification of branching in model three-arm star polyethylene

The versatility of a novel scaling approach in quantifying the structure of model well-defined 3-arm star polyethylene molecules is presented. Many commercial polyethylenes have long side branches, and the nature and quantity of these branches varies widely among the various forms. For instance, low-density polyethylene (LDPE) is typically a highly branched structure with broad distributions in branch content, branch lengths and branch generation (in hyperbranched structures). This makes it difficult to accurately quantify the structure and the inherent structure-property relationships. To overcome this drawback, model well-defined hydrogenated polybutadiene (HPB) structures have been synthesized via anionic polymerization and hydrogenation to serve as model analogues to long-chain branched polyethylene. In this article, model 3-arm star polyethylene molecules are quantified using the scaling approach. Along with the long-chain branch content in polyethylene, the approach also provides unique measurements of long-chain branch length and hyperbranch content. Such detailed description facilitates better understanding of the effect of branching on the physical properties of polyethylene. © 2012 American Chemical Society.

Ramachandran, R., Beaucage, G., Rai, D. K., Lohse, D. J., Sun, T., Tsou, A. H., … Hadjichristidis, N. (2012). Quantification of Branching in Model Three-Arm Star Polyethylene. Macromolecules, 45(2), 1056–1061. doi:10.1021/ma2021002

This work was funded by ExxonMobil Research & Engineering Co. and the University of Cincinnati Graduate School Distinguished Dissertation Completion Fellowship. This work utilized facilities supported in part by the National Science Foundation under Agreement No. DMR-0454672. We acknowledge the support of the National Institute of Standards and Technology (NIST), U.S. Department of Commerce, for providing the neutron research facilities used in this work. Research at Oak Ridge National Laboratory's High Flux Isotope Reactor was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. We thank B. Hammouda and S. Kline at NIST and Y. Melnichenko at ORNL for their valuable support during the beamtime.

American Chemical Society (ACS)



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