Preparation And Analysis Of Thermo Sensitive Gels

The thermosensitive copolymers were synthesized by free radical aqueous solution copolymerization.Hydrophilic hydrogels were synthesized by N-isopropylacrylamide(NIPAm) and methacrylamide(MAm) with crosslinker N,N'-methylenebisacrylamide(BIS) in water,and hydrophobical gels were synthesized by N-isopropylacrylamide(NIPAm) and butyl methacrylate(BMA) with crosslinker polyethylene glycol diacrylate(PEGDA) in tetrahydrofuran(THF).The effects of the physical properties were studied by the change of monomer contents and cross-linker concentrations.The chemical structures were analysed by infrared spectra , the thermo-responsive behaviors of copolymers were investigated by differential scanning calorimetry,and the microcosmic morphology of gels were investigated by scanning electron microscope.The properties and influences of the gels were studied under different condition;The relation between capability and properties was investigated in order to synthesize better function gels.Hydrophilic P(NIPAm-co-MAm) gels and hydrophobical P(NIPAm-co-BMA) gels with different properties were sythsized,and the effect of composition ratios and cross-linker concentrations on swelling,water retention,mechanism strength,the lowest critical solution temperature(LCST) of gels was discussed.The experiment proved:with the increasing of hydrophilic monomer ratio in the gels,the swelling ratio of P(NIPAm-co-MAm) and P(NIPAm-co-BMA) increased,water retention of P(NIPAm-co-MAm) increased,water retention of P(NIPAm-co-BMA) decreased.The mechanism strength and LCST of P(NIPAm-co-MAm) increased with hydrophilic monomer ratio increased,and also the LCST of P(NIPAm-co-BMA) increased with hydrophilic monomer ratio increased. With the increasing of cross-linker concentrations,the swelling ratio of P(NIPAm-co-MAm) and P(NIPAm-co-BMA) decreased,water retention of P(NIPAm-co-MAm) increased,and cross-linker concentration is no effect on LCST of P(NIPAm-co-MAm) and P(NIPAm-co-BMA).