Enhancing Of Agar/Polyacrylamide Double Network Hydrogel And Study On Their Carbon Dots Modified Fluorescent Hydrogel

As a new type of "soft" and "wet" materials,hydrogels have broad application prospects because of their excellent water absorption and water retention capacity and good biocompatibility.However,the weak mechanical properties of traditional hydrogels greatly restrict the application scope of hydrogels.In this paper,a high-strength gar/polyacrylamide(Agar/PAAM)double network(DN)hydrogel is synthesized,and carbon quantum dots are added to prepare a functional composite hydrogel,which can be used for the detection of heavy metal ions in water,and broadens the application scope of such polymer materials.Firstly,in this paper,through the "one pot" method,agar(Agar)and acrylamide(AM)as monomers,N 'N-methylenebisacrylamide(MBA)as a cross-linking agent,2-hydroxyl-4'-(2-hydroxyethoxy)-2-methyl phenylacetone(12959)as a photoinitiator,through UV-induced free radical polymerization to form Agar/PAAM double network hydrogel.By optimizing the process conditions and changing the different ratios of materials,the conditions with the best mechanical performance results are found:The Agar concentration is 20 mg/mL,the AM concentration is 4 mol/L,and the cross-linking agent MBA is 0.05%of the AM mole fraction respectively;the corresponding maximum tensile breaking strengths is 0.92MPa.On the basis,the effects of polyvinyl alcohol(PVA)and poly-N-vinylpyrrolidone(PVP)on the mechanical enhancement of DN gel were discussed.when the amount of PVP-K90 is 1%of the AM mass fraction,the maximum tensile breaking strength is increased by 10%to 1.01 MPa;when the amount of PVA-1788 is 1%of the AM mass fraction,the maximum tensile breaking strength is increased by 16%to 1.06MPa.Besides,in thi's paper,fluorescent carbon quantum dots made of citric acid and urea are doped into DN gel by nanocomposite method to prepare fluorescent double network hydrogel,and study its detection effect of metal ions in water.The results show that the addition of fluorescent carbon quantum dots not only improves the mechanical properties of the hydrogel,but also makes the fluorescent dual network hydrogel have fluorescence quenching effect on various metal ions in water.Among them,Fe3+has the best detection effect,and has a good linear relationship in the range of Fe3+concentration of 80-160 ?mol/L,which can used to detect Fe3+in water.In summary,this paper successfully prepared Agar/PAAM DN gel with higher mechanical strength and optimized its process parameters.The carbon quantum dots with stable fluorescence phenomenon are introduced into the DN gel network structure,while improving its mechanical strength,it also gives the gel fluorescence performance.Due to its portability and visualization characteristics,it can be used for rapid detection of metal ions in water.