Deuterium-labeled polyolefins: Exchange, characterization, and applications

The polyolefins manufacturing industry has taken advantage of the broad array of physical properties available from simple combinations of hydrocarbon monomers, leading to the ubiquity of these materials in our daily lives. Properties can be tuned by the type, amount, and arrangement of monomers and comonomers, as well as through long-chain branching; each of these structural elements additionally has some distribution within and across molecular weight, making resin design a complex multi-dimensional problem. While material performance continues to improve, understanding of structure-property relationships often remains elusive due to the combination of structural complexity and chemical simplicity, which masks the role of particular components in resin performance.

Isotopic labeling is a powerful tool that is well-suited to the challenges posed by polyolefin systems. Recent work has identified facile, inexpensive hydrogen-deuterium exchange reactions for accomplishing such labeling on polyolefins. These labeling reactions enable new studies isolating particular labeled components in polyolefin systems, but also create a need for new characterization and analysis tools to identify the arrangement and distribution of deuterium on the polymer chains. Additionally, the exchange itself is surprisingly sensitive to the solvent used during reaction as well as the stereochemistry of the polymer, pointing toward mechanisms of adsorption that have analogues in other polymer systems. Here, studies relating the exchange reactions, characterization methods, and use of labeled polymers in applied systems will be reviewed.