Study On Synthes Is And Thermo-Sensitive Property Of The Modified Poly(N-isopropylacrylamide)

This dissertation,using the methods of Atom transfer radical polymerization,through two different ways,tried to modify Poly(N-isopropylacrylamide) and to change its LCST by the modified methods,and made deep research.First,in a sealed system filled with nitrogen,N-isopropylacrylamide was polymerized using 2-chloropropionates with a series of hydrophobic aryl groups as initiators and CuCl/Me₆TREN as catalyst system in DMF/water mixed solvent at 20℃.Kinetic experiments showed that the polymerization process was controllable and found that the differences in the polymerization rates were related to the number of the aromatic rings.The bigger aromatic ring number is,the easier polymerization becomes.After modification,the performance of terminal hydrophobic was enhanced,and affected the performance of the polymer solution.Thus,LCST of PNIPAM dropped from 32℃to 23℃,and the bigger aromatic ring number is,the more the LCST dropped.But after introducing theβ-cyclodextrin, only end-functionalization of PNIPAM with(2-phenyl)-2-chlorophenyl propionate was formed withβ-cyclodextrin as complexs,and the hydrophobic interactions of this complexs chain was weakened and the LCST of the polymer rose 5.6℃again.Another modified was consisted in linking initiator groups by reaction of 2-chloroproponates with the dextran,which was partially acetylated.Poly N-isopropylacrylamide was grafting from dextran using the ATRP.And,the outcome's structure was affirmed by the methods of IR spectra and ¹HNMR.