Preparing functional polyolefins by post-polymerization functionalization accesses backbone and pendant architecture otherwise unavailable by commercial free radial polymerization (FRP), broadening the window of accessible properties. This confers an advantage inherent to polymer-to-polymer upcycling as compared to commercial FRP. This dissertation investigates the effects of chain and pendant architecture on the structure-property relationships of associating polyolefins, contributing to an emerging polymer-to-polymer upcycling strategy by dehydrogenation and functionalization of polyethylene. Functionalizing poly(cyclooctene) (PCOE), an analog for partially dehydrogenated high density polyethylene, with OH-containing pendants followed by hydrogenating the remaining unsaturation generates analogs for poly(ethylene-co-acrylic acid) (EVOH). Functionalizing with bulky thioether ethyl hydroxyl pendants disrupts crystallization, and at functionalization of more than 15 % of ethylene units the material becomes amorphous. By contrast, adding OH directly to the backbone to generate a linear EVOH (LEVOH) preserves crystallinity at all levels of functionalization. LEVOH exhibits greater crystallinity and crystallization kinetics than commercial EVOH, suggesting superior barrier properties. This difference in morphology contributed to a disparity in surface and adhesive properties between these two OH-functionalized polymers.
Attaching thioether n-methylene carboxylic acid pendants to PCOE enabled an investigation into the role of both extents of functionalization and pendant size on properties of acid-containing polyolefins. Controlled thiol-ene click chemistry attached three different pendants of three different methylene spacer lengths. Neither morphology nor thermal properties exhibit a significant pendant length dependence. However, both functionalization and pendant length influence the rubbery storage modulus, as described by the backbone equivalence model. This model effectively fits the rubbery plateau modulus to the molar mass per backbone bond, accounting for both functionalization and pendant length. Finally, functionalizing PCOE with ethyl acrylate generates a copolymer with remarkable extensibility and high toughness, even at ≤ 3 % functionalization. Dehydrogenation typically generates C=C on < 5 mol% of ethylene units. This suggests functionalizing dehydrogenated PE with ethyl acrylate produces a material with sufficient properties for application. Overall, this dissertation investigates the influence of extent of functionalization, chain architecture, and pendant size on the morphological, thermal, surface, and mechanical properties of alcohol, acid and acrylate functionalized PCOE.