Based On The Synthesis And Properties Of The Copolymer Of Dmaema And Nipam Hydrogel

In recent years,stimuli-responsive polymers or intelligent polymers and their hydrogels have attracted some researcher's attention.Some properties of these polymers can respond to the small changes of the external environment conditions such as temperature,pH,ionic strength,electric field and so on.These changes are reversible.Due to the special properties of intelligent polymers,they have been used in many areas such as drug delivery,tissue engineering,biosensors,separation and so on.A series of different composition poly((dimethylamino) ethyl methacrylate-co-N-isopropylamide) (P(DMAEMA-co-NIPAM)) random copolymers were synthesized by free radical copolymerization. The phase behavior of the random copolymers in aqueous solution and their pH sensitivities effected by poly(acrylic acid)(PAA) were studied by UV-vis transmittance measurement and fluorescence techniques.The results demonstrated that the temperature and pH-sensitivities for random copolymers in aqueous solution were mutually influenced.The addition of PAA greatly influenced the pH sensitivity of P(DMAEMA-co-NIPAM) at about pH 4.The modulation of PAA on the pH sensitivity of P(DMAEMA-co-NIPAM) may be used in design of novel sensitive gels.A novel temperature- and pH-sensitive copolymer hydrogel composed of N-isopropylacrylamide (NIPAM) and dimethylaminoethyl methacrylate(DMAEMA) was synthesized by free radical solution polymerization.The composition and surface morphology of the hydrogels were investigated by means of Flourie Infrared Spectra and scanning electron microscope.The swelling behavior,deswelling and swelling kinetics of the copolymer hydrogels in different pH mediums were investigated.The results demonstrated that the copolymer hydrogel had temperature and pH double sensitivities.Compared with conventional acrylic acid hydrogels,the pH sensitivity of synthesized copolymer hydrogel was contrary,and the copolymer hydrogels were in swollen state in acid medium.The more the DMAEMA content in copolymer hydrogel was,the bigger the network pore size of the copolymer hydrogel was in acid medium,and the higher the swelling degree of the copolymer hydrogel was.Compared with the conventional PNIPAM hydrogel,the deswelling rate of the copolymer hydrogel was faster.The swelling rate of the copolymer hydrogel was much slower than the deswelling rate.The graft hydrogels have unique structure and free mobile grafted chains,so they have faster response rate than that of normal hydrogels.A series of different composition poly((dimethylamino) ethyl methacrylate-g-N-isopropylamide)(P(DMAEMA-g-NIPAM)) graft hydrogels were synthesized by free radical copolymerization and macromonomer technique.The composition and surface morphology of hydrogels were investigated by means of Flourie Infrared Spectra and scanning electron microscope.The swelling behavior,deswelling and swelling kinetics of the graft copolymer hydrogels were investigated.The results demonstrated that the graft copolymer hydrogel had temperature and pH double sensitivities.The more the PNIPAM macromonomer content was, the faster the deswelling rate was,and the slower the swelling rate was.