1 research outputs found
Thermoresponsive copolymers with pendant d-galactosyl 1,2,3-triazole groups: Synthesis, characterization and thermal behavior
A galactose containing glycomonomer has been synthesized by copper catalyzed azide\u2013alkyne cycloaddition
reaction (CuAAC) of 6-azido-6-deoxy-1,2:3,4-di-O-isopropylidene-a-D-galactopyranose with
propargyl acrylate. This monomer was subjected to homopolymerization and copolymerization with
N-isopropylacrylamide (NIPAm) at different compositions by free radical polymerization using 2,20-azobisisobutyronitrile
(AIBN) as an initiator. The composition of the copolymer was determined by 1H-NMR
spectroscopy. Upon acid hydrolysis of acetonide protected polymers, water-soluble deprotected polymers
were obtained. The polymers were characterized and confirmed by NMR, IR, GPC and thermal analytical
techniques. The protected and deprotected copolymers showed a sharp cloud-point temperature and a
linear correlation was obtained between the lower critical solution temperatures (LCST) and the
concentration of glycomonomer in the copolymers. This allows tuning the thermal response by simply
altering the copolymer composition. Water contact angle experiments showed the changes in the
hydrophilicity of copolymers with compositions that supported the LCST results. The glass transition
temperature of protected copolymers followed a regular monotonic decreasing trend with increasing
glycomonomer content, whereas Tg of deprotected copolymers increased due to H-bond interaction. The
attempts to develop thermoresponsive polymers having LCSTs at physiological temperature were successfu