Study On Synthesis Of Poly（allyl-cellulose） Hydrogel Under NaOH/urea/H₂O Solvent System And Its Performance

Cellulose has attracted much attention because of its environmental,non-toxic,renewable,biodegradable properties,followed by that based on cellulose hydrogels have also attracted great interest from reseachers.At present,most people use cellulose or its derivatives and synthetic polymers,such as polyethylene glycol,polyacrylamide etc,to prepare a high mechanical properties of the composite hydrogel,but a single cellulose or derivative hydrogel is relatively small,so that the cellulose has not been more fully applied,and the traditional single cellulose or derivative hydrogel mechanical properties are poor and when has a large deformation,it presents a rupture,resulting in a large extent limited in practical application of hydrogels in certain fields.In this paper,the synthesis of cellulose hydrogel research provides a scientific and technical support to solve this problem.The main contents and results of this study are as follows:1.Synthesis of cellulose ether(AHP-cellulose)By Na OH/urea aqueous solution as solvent at low temperature to dissolve cellulose,and allyl glycidyl ether(AGE)as modifier,were synthesized the cellulose ether(AHP-cellulose)with a double bond.Compared with the synthesis method under heterogeneous conditions,homogeneous synthesis has many advantages,such as more uniform,easily to control,so that it can be functionalized.The structure,crystal structure and stability of the modified cellulose were proved by liquid 1HNMR,13 CNMR,FT-IR,XRD and TGA analysis.The results showed that the crystallinity of the modified cellulose decreased greatly,and it was stable.The solubility of modified cellulose in water is related to the degree of substitution.When the degree of substitution reaches to a certain amount,such as 0.29,it can be completely dissolved in water at the same time.2.Preparation of Poly(AHP-cellulose)hydrogel with oxidation reduction radical polymerization by one pot methodBy AHP-cellulose with double bond as raw materials,ammonium persulfate(APS)and N,N,N’,N’-Tetramethylethylenediamine(TEMED)as redox initiator system,has a polymerization of free radicals at room temperature to form gel.This chapter reports that the oxidation reduction of free radical polymerization has a low polymerization temperature and polymerization speedy,and prepared by one pot method to synthesis high compression performance of Poly(AHP-cellulose)hydrogel,laid the foundation to preparate double network hydrogel.Based on the principle of reaction,surface morphology and mechanical properties,the effects of the degree of substitution of cellulose,concentration of APS and TEMED on the mechanical properties were discussed.The experimental results show that the hydrogel surface is porous and fluffy structure.When the cellulose substitution degree is 0.52 and the concentration of APS and TEMED is 0.01g/g,the hydrogel has the highest compressive strain of 0.78,corresponding to stress of 0.13 MPa.3.Preparation of Poly(AHP-cellulose)double network hydrogel by two step methodIn this paper,a novel method for preparing cellulose hydrogel with high flexibility and high elasticity is proposed by combining the first network obtained by free radical polymerization with the physically cross-linked as second network.In this chapter,the redox free radical polymerization to prepare Poly(AHP-cellulose)hydrogel as the first network,then be immersed in saturated NaCl solution to obtain second crosslinking network,to form of Poly(AHP-cellulose)hydrogel.The gel mechanism,surface morphology and crystallinity of the double network hydrogels were analyzed.The effects of different conditions on mechanical properties were discussed.The experimental results show that the appearance of double network hydrogel is milky white,and can be used for various deformation.In addition,the physical crosslinking network and chemical crosslinking network of double network hydrogels are distributed evenly.When the degree of substitution of cellulose was 0.52,APS and TEMED concentration was 0.01g/g,superior double network hydrogels has a good flexibility.