The Preparation And Properties Study Of High-strength And Self-Healing Hydrogel Based On Multivalent H-bonds

Hydrogel are composed of a polymer with three-dimensional network and a large amount of solvent.Hydrogels are widely used in biomedicine,tissue engineering and other fields.The combination of high strength and self-healing properties is one of the important Works in the hydrogel research.multivalent H-bonds have the advantages of dynamic reversibility and good stability.Introducing multivalent H-bonds into the three-dimensional network of hydrogels to prepare high-strength and self-healing hydrogels has become the focus of Hydrogel researchers.However,the currently reported multivalent H-bonds hydrogels have many shortcoming,such as complex preparation processes,difficulty of purification,and low yields.These shortcoming limit it application.To solve these problems we adopts some convenient method to prepare multivalent H-bonds hydrogels.We prepared multivalent H-bonds hydrogels by controlling the number of hydrogen-bond acceptor-donor units on the polymer.The results are as follows:（1）Select low-cost polyvinyl alcohol as raw material,and use one-step method to modify it.PVA was first reacted with N,N’-carbonyldiimidazole and then reacted with glycine amide to prepare hydrogel PVA-CDI-GA containing urethane and amide groups.The results show that the higher the functionalization rate of PVA-CDI-GA,the better the mechanical properties and self-healing properties of the gel.The tensile strength of PVA-CDI-GA₁₀₀reached 0.51 MPa at a maximum strain of 4.5.Measures such as freeze/thaw cycle can improve the mechanical properties of PVA-CDI-GA gels.（2）Selecting low-cost N-methylol acrylamide as raw material,the hydrogel PNMA-CDI was prepared by prepolymer method.The results show that the mechanical properties,self-healing properties and stability in water of PNMA-CDI are improved compared to PNMA gel by modification with N,N’-carbonyldiimidazole and drying-reswelling treatment.The tensile strength of PNMA-CDI₁₀₀-D reached0.51 MPa at a maximum strain of 4.5 and it self-healing efficiency reached63%.These results suggest that increasing the number of hydrogen-bond acceptor donor units can effectively improve the mechanical properties,self-healing properties,and stability of hydrogels.（3）We synthesized MEGA,a monomer containing urea and amide units,and SCMHMA,a monomer containing urea and pyrimidinone units.The monomer MEGA is slightly soluble in water,and the monomer SCMHMA is insoluble in water.Prepar the hydrogels P（SCMHMA-co-NMA）,P（MEGA-co-NMA）,P（SCMHMA-co-MEGA）and PMEGA by homopolymerization or copolymerization using surfactant SDS or using good solvent DMSO,and completed structural characterization and performance testing.The results show that the hydrogels prepared by MEGA and SCMHMA have poor mechanical strength.