New graft copolymers were synthesized by graft-ing N-vinylcaprolactam onto dextran.Their composition and structure were investigated by elemental analyses,infrared spectra and thermogravimetric analyses.By optical tra...New graft copolymers were synthesized by graft-ing N-vinylcaprolactam onto dextran.Their composition and structure were investigated by elemental analyses,infrared spectra and thermogravimetric analyses.By optical transmit-tance measurements,it was found that the aqueous solutions of these graft copolymers showed a temperature-dependent transmittance change due to the introduction of thermosensi-tive poly(N-vinylcaprolactam)graft chains.Moreover,the lower critical solution temperature(LCST)of the graft copolymer in aqueous solution was dependent on its grafting extent and concentration.The LCST value was found to increase with the increase of the grafting extent and decrease with the increase of the copolymer concentration.With these stimuli-response properties,such polysaccharide derivative may hold potential applications in biomedicine and biotechnology.展开更多
The ABA block copolymers of polyethylene glycol(PEG) as B block and poly N isopropylacrylamide(PNIPA) as A block were synthesized by means of radical polymerization with one step. The block polymers exhibit ther...The ABA block copolymers of polyethylene glycol(PEG) as B block and poly N isopropylacrylamide(PNIPA) as A block were synthesized by means of radical polymerization with one step. The block polymers exhibit thermosensitive behavior at a higher LCST temperature than homopolymer of NIPA.展开更多
基金supported by the National Natural Science Foundation of China(Grants No.20676155,No.30470476,No.20273086)Natural Science Foundation of Guangdong Province(Grants No.039184,No.06023103)+1 种基金Department of Science and Technology of Guangdong Province(Grant No.2004B33101003)Program for New Century Excellent Talents in Universities of China(NCET-04-0810).
文摘New graft copolymers were synthesized by graft-ing N-vinylcaprolactam onto dextran.Their composition and structure were investigated by elemental analyses,infrared spectra and thermogravimetric analyses.By optical transmit-tance measurements,it was found that the aqueous solutions of these graft copolymers showed a temperature-dependent transmittance change due to the introduction of thermosensi-tive poly(N-vinylcaprolactam)graft chains.Moreover,the lower critical solution temperature(LCST)of the graft copolymer in aqueous solution was dependent on its grafting extent and concentration.The LCST value was found to increase with the increase of the grafting extent and decrease with the increase of the copolymer concentration.With these stimuli-response properties,such polysaccharide derivative may hold potential applications in biomedicine and biotechnology.
文摘The ABA block copolymers of polyethylene glycol(PEG) as B block and poly N isopropylacrylamide(PNIPA) as A block were synthesized by means of radical polymerization with one step. The block polymers exhibit thermosensitive behavior at a higher LCST temperature than homopolymer of NIPA.
