Preparation And Study Of Environmentally Sensitive Hydrogels Based On Polyethylene Glycol Copolymer

The temperature sensitive material is a hotspot in recent research.In this paper,a series of temperature and pH sensitive polymer hydrogels were synthesized and studied.The specific work is as follows:1.In the aqueous solution,oligo(ethylene glycol)methyl ether acrylate(OEGA)(Mn=480)and ethylene glycol methyl ether acrylate(MEA)were used as comonomers,a series of temperature sensitive P(MEA-co-OEGA)polymer hydrogels were successfully prepared by free radical copolymerization.The structures were confirmed by solid-state NMR(1H/MAS),the thermo-sensitive properties were determined by UV-visible spectrophotometer spectroscopy(UV-vis)and equilibrium swelling ratio(ESR),the results show that the low critical phase transition temperature(LCST)is controllable.With the combination of high field static solid nuclear magnetic resonance'(NMR)and low field nuclear magnetic resonance(LF-NMR),the movement of hydrogels and the different states and relative contents of water in hydrogels were explored.The microscopic mechanism of the thermosensitivity of the hydrogels was obtained.2.On the basis of P(MEA-co-OEGA)copolymer hydrogel,N-N-dimethylaminoethyl methacrylate(DMAEMA)was introduced into free radical copolymerization with MEA and OEGA,P(MEA-co-OEGA-co-DMAEMA)hydrogels with temperature and pH sensitivity were obtained,and they can be used as a carbon dioxide response device,dimming material and drug control release carrier.3.Semi-interpenetrating network(semi-IPN)cellulose 'hydrogels were prepared by in-situ polymerization in aqueous solution of carboxymethyl cellulose(CMC)using poly(ethylene glycol)methyl ether methacrylate(O5EGA)(Mn=300)as monomer.The ESR test showed that the more the CMC content,the greater the swelling rate,the faster the deswelling,the addition of comonomer MEA could adjust its LCST to 35 ?,close to the body temperature.This kind of hydrogel is expected to be applied in the field of biomedicine.