Syntheses and the Study of Strongly Hydrogen-Bonded Poly(vinylphenol-b-vinylpyridine) Diblock Copolymer through Anionic Polymerization

A series of poly(vinylphenol- b -vinylpyridine) (PVPh- b -P4VP) block copolymers were prepared through anionic polymerizations of 4- tert -butoxystyrene with 4-vinylpyridine followed by subsequent selective hydrolysis of the 4- tert -butoxystyrene protective groups. Infrared spectrum analysis suggests that this block copolymer possesses strong hydrogen-bonding interaction between the hydroxyl group of PVPh and the pyridine group of P4VP. DSC analyses indicate that these PVPh- b -P4VP copolymers always have higher glass transition temperatures than the corresponding PVPh/P4VP miscible blends obtained from DMF solution. However, the thermal behavior of PVPh- b -P4VP diblock copolymer shows a similar T g value with the PVPh/P4VP blend complex obtained from methanol solution at a 1:1 (PVPh:P4VP) molar ratio. We proposed that the polymer chain behavior of the PVPh/P4VP blend from DMF solution is separated coils. However, by increasing the hydrogen bonding for PVPh- b -P4VP diblock copolymer, a polymer complex aggregate is proposed, which is similar to the PVPh/P4VP blend complex from methanol solution. The spin−lattice relaxation time in the rotating frame ( ) based on solid-state NMR analysis is able to provide positive evidence that the polymer complex aggregate in the diblock copolymer has a shorter value than the separated coils in the miscible blend.