Synthesis and characterization of low molar mass end-functionalized homo- and copolymers with ureidopyrimidone, UPy groups

摘要

Anionic polymerization techniques along with functional initiation and/or functional termination reactions were employed for the synthesis of end-functionalized polymers composed from polystyrene (PS), polyisoprene-1,4 (PI), and polybutadiene-1,4 (PBd) chains bearing -OH end groups. Specifically, PS-OH, HO-PS-OH homopolymers, PS-b-PI-OH and PI-b-PS-OH block copolymers, HO-PS-b-PI-b-PS-OH triblock copolymers, and PS(PBd-OH)(2) miktoarm star copolymers were prepared. The -OH functions were transformed into 2-ureido-4-pyrimidone, UPy, groups leading to the synthesis of the corresponding functionalized polymers. The UPy groups interact through the formation of strong hydrogen bonds. The aggregation behavior of selected samples was studied by a variety of techniques, such as size exclusion chromatography, dilute solution viscometry, dynamic light scattering, differential scanning calorimetry, thermogravimetric analysis, melt rheology, small angle X-ray scattering, and atomic force microscopy. It was found that in the solid state and in non-polar solvents, the UPy-terminated chains associate leading to the formation of dimers and larger aggregates. This systematic study presents a library of useful materials for potential applications and for fundamental studies linking associations, molecular structure, and macroscopic properties.