Designs, Synthesis And Performances Reasearch Of Thermo-responsive Polymer

Stimuli-responsive polymers have attracted a great deal of research interest over the past severaldecades. They can convert environmental stimulus, such as temperature, pH, ironic strength, and glucoseconcentration, into the signal to trigger the change in physical properties of the polymers. So that it haschanged for the physical and chemical properties of polymers. The polymers have received more and moreconcern for special performances, especially in biological medicine and engineering material.In this paper, a series of thermo-responsive copolymers were designed and prepared via severalpolymerization methods. The parts mainly composed of this paper as following:（1） Firstly， Alkyne bromopoly（ethylene glycol）（alkyne-PEG-Br） were synthesized by a seriesof functionalization methods. Alkyne-PEO-b-PNIPAM was obtained by atom transfer radicalpolymerization （ATRP） of N-isopropylacrylamide（NIPAM） using alkyne-PEG-Br as initiator andCuBr/Me6TREN as catalyst. The composition and structure of these copolymers were characterized by gelpermeation chromatography （GPC） and¹H nuclear magnetic resonance （¹H NMR） spectroscopy.（2） The brush polymer PBAMO-g-（PEG-b-PNIPAM） and star polymer β-CD-g-（PEG-b-PNIPAM）were synthesized by “click” reaction, in which alkyne-PEO-b-PNIPAM was introduced successfully intothe backbone poly（3,3-bis（azidomethyl）oxetane）（PBAMO） and core heptakis（6-deoxy-6-azido）-b-cyclodextrin （（N₃）₇-β-CD）. The construction of polymers were characterized by¹HNMR,13CNMR, FT-IR and GPC and the thermo-responsive porformrnces were investigated by UV. It wasshown that the lower critical solution temperature （LCST） of PBAMO-g-（PEG-b-PNIPAM） is33.5oC, andthat of β-CD-g-（PEG-b-PNIPAM） is40.0oC.（3） Firstly, PAGEs were synthesized by anionic ring-opening polymerization of AGE using C2H5ONaas initiator. Secondly, a series of block copolymers PAGE-b-PCL were synthesized by ring-openingpolymerization of CL using PAGE as macroinitiator in the presence of Sn（Oct）₂. And then linearamphiphilic triblock copolymers PAGE-b-PCL-b-PEG were prepared by condensation reaction ofPEG-COOH to PAGE-b-PCL in the presence of DCC and DMAP at room temperature. Finally, the amino acid molecules were conjugated to the pendant double bonds of the copolymers PAGE-b-PCL-b-PEG viafree radical addition reaction to give the ABC triblock copolymer PAGE/cys-b-PCL-b-PEGs. The polymerswere characterized by¹HNMR and GPC. The performance of self-assembly behavior was token by DLSand TEM for preparation of micellar solution...