Study On Synthesis And Properties Of Stimulated Responsive Hydrogels By Sodium Lignosulfonate

Hydrogel is a classic soft material with high water content in 3D flexible network,with many structural and functional advantages of layered porous structure,viscoelasticity,transparency,stretchability and biocompatibility.In this paper,sodium lignosulfonate(LGSNa+),acrylamide(AAm)and N-isopropylacrylamide(NIPAAm)are used as raw materials,and N,N'-methylenebis(acrylamide)(MBA)is used as a crosslinking agent,With ammonium persulfate(APS)as the initiator and N,N,N',N'-tetramethylethylenediamine(TMEDA)as the accelerator,three kinds of sodium lignosulfonate stimulating responsive hydrogels were prepared.(1)The grafting method was used to connect the sodium lignosulfonate into the polyacrylamide hydrogel to synthesize polyacrylamide-sodium lignosulfonate hydrogel,and the ammonium molybdate was introduced into the hydrogel network through the soaking process display.UV-Vis,FT-IR and SEM respectively measured the absorbance and transparency,structure and morphology of sodium lignosulfonate-polyacrylamide hydrogel.The UV-Vis measurement results show that the hydrogel has low cost,easy preparation,and excellent performance of rapid response within 5 minutes.FT-IR measurement results indicate that sodium lignosulfonate was successfully incorporated into polyacrylamide hydrogel.SEM research results show that the hydrogel shows a dense structure after it is completely dried,which makes the hydrogel not easy to fade after photochromism.(2)Through hydrogen bonding,a stretchable and transparent flexible electrosensing hydrogel composed of polyvinyl alcohol(PVA)and interpenetrating sodium lignosulfonate-polyacrylamide(LGSNa+-PAAm)network was synthesized.The universal testing machine,UV-Vis,FT-IR,SEM and electrochemical workstation respectively sense the mechanical properties,transparency,structure,morphology and pressure of sodium lignosulfonate/polyacrylamide/polyvinyl alcohol flexible hydrogel Determination of performance.The FT-IR test results show that PVA successfully inserted into the hydrogel through hydrogen bonding.The mechanical test results show that the tensile strain of hydrogel increases from 88%to 296%,and the compressive stress of hydrogel increases from 0.195 MPa to 0.243 MPa,indicating that the addition of PVA improves the flexibility of hydrogel.UV-Vis test results show that the hydrogel film has optical transparency.The SEM research structure shows that the hydrogel surface has uniform self-patterned microstructures.The presence of wrinkled microstructures and interconnected ridges on the rough surface can increase the contact area and sensitivity of the hydrogel sensor.The measurement results of pressure sensing performance show that the strain sensor based on flexible hydrogel can detect small deformation and human voice recognition.(3)LGSNa+was connected to NIPAAm hydrogel to synthesize a LGSNa+hydrogel with temperature-sensitive response.FT-IR and SEM measured the structure and morphology of sodium lignosulfonate/poly-N-isopropylacrylamide hydrogel.FT-IR test results show that LGSNa+is successfully inserted into NIPAAm hydrogel.SEM test results show that the density and pore size of pores increase with the increase of LGSNa+ content,and then show a trend of increasing first and then decreasing.When the content of LGSNa+ is 0.5 mg/mL,the pores of the hydrogel are dense and the pore size increases.However,with the further increase of LGSNa+ content,the pores of the hydrogel were sparse,and the swelling/de-swelling behavior analysis showed that the content of LGSNa+ in the hydrogel was 0.5 mg/ML,the swelling rate increased to 13.99,and when the content of LGSNa+ further increased to 2.0 mg/mL,the swelling rate of the hydrogel is reduced to 8.294,and the large pore size is conducive to water absorption and dehydration;the drug controlled release results show that the factors controlling the release rate vary with the type of drug,and the diffusion of methylene blue(MB)is mainly It is a chemical interaction,and the diffusion of folic acid(FA)is mainly physical diffusion.