Functionalization of commercial polymers via novel covalent modification strategies

The chemical functionalization and modification of existing polymers for enhancing or diversifying their physicochemical and mechanical properties remains a key objective in macromolecular science. In particular, structural tailoring of widely available commercial polymers presents unique opportunities for the development of advanced functional materials. In this doctoral study, two distinct commercially important polymers were structurally functionalized using different synthetic strategies. In the first part, poly(vinyl chloride) (PVC) was covalently modified via an organometallic Barbier-type reaction. This approach involved the in situ generation of nucleophilic alkyl-magnesium chloride species from inherent alkyl chloride groups in the polymer backbone using elemental magnesium, followed by their nucleophilic addition to various aldehyde and epoxide substrates. The developed methodology provided high functionalization efficiencies (above 84%) and allowed for control over functionality levels through simple adjustment of the magnesium-to-backbone ratio. In the second part, unsaturated styrene–isoprene–styrene (SIS) copolymer was modified through UV-induced Paternò–Büchi [2 + 2] photocycloaddition reactions using aldehyde derivatives. The reactive isoprene double bonds were covalently grafted via oxetane ring formation. Furthermore, bifunctional aldehydes were employed to achieve covalent crosslinking between polymer chains, leading to the formation of organogels with tunable crosslinking density and physical properties. In both approaches, the modification processes were thoroughly characterized by ¹H NMR, FT-IR, SEC analyses, and contact angle measurements. The results demonstrate that both PVC and SIS can be readily functionalized using these versatile methods, offering promising pathways for the design of next-generation functional polymeric materials.