Construction And Properties Of Hydrogel System Based On Macromolecule Microsphere Crosslinking And Hydrophobic Association

Hydrogels are a soft and wet material with strong water absorption capacity,this material has a three-dimensional network structure.In that it is consisted of water and the hydrophilic polymer network,its structure has similar characteristics to biological tissues.Hydrogels have been widely used in biological fields such as biomedicine,tissue engineering,and drug loading.However,the traditional hydrogels lacks the mechanism of dissipating energy in the system,and the gel network is non-uniform,which causes the traditional hydrogels to be easily broken and have poor mechanical properties.This defect of traditional hydrogels has limited its application in certain high impact areas,such as artificial blood vessels,artificial cartilage,artificial tendons,and the like.Therefore,it is of great practical significance to try to develop hydrogels with excellent mechanical properties.In this article,we use the acrylamide as a hydrophilic monomer,hexadecyl methacrylate as a hydrophobic monomer,the different components of hydrophobic association hydrogel prepared by micellar polymerization method.The uniaxial tensile test and the Mooney-Rilvin theory were used to analyze the structural parameters of the gel network.The experimental results showed that with the increase of the content of emulsifier and hydrophobic monomer,the strength of the gel showed a tendency to rise and then decrease When the content is 4%,the gel strength is the largest,and when the hydrophobic monomer content is 0.351%,the gel strength reaches the maximum.When the content of main monomer increases,the fracture stress increases monotonously,while the elongation at break is the opposite.Then we introduced bifunctional macromolecular microspheres prepared by traditional emulsion polymerization into a hydrophobic association system to improve the mechanical properties of hydrogels.First,in the aqueous solution of sodium dodecyl sulfate,using butyl acrylate as a monomer and dicyclopentyl acrylate as an intermolecular cross-linking agent,the hydrophobic molecular microspheres(PBA-MMs)pendents double bonds on the surface were prepared.Then using PBA-MMs as the center of chemical cross-linking and hydrophobic association,the acrylamide / hexadecyl methacrylate as the polymerization monomer,macromolecular microsphere cross-linked hydrophobic association(P(AAm/HMA)-MMs)hydrogels were prepared by radical polymerization.The effects of the particle size of PBA-MMs and thetype of crosslinking agent,the content of each component in the gel system,and the order of system initiation on the mechanical properties of the gel were investigated.The experimental results of the tensile test show that the mechanical properties of the gel have been significantly improved compared to the pure hydrophobic associative hydrogel.When the crosslinking agent is DCPA,the particle size is 300 nm,the ratio of PBA-MMs weight and emulsifier weight to water quality are 0.45% and 0.3%,respectively,the ratio of hydrophobic monomer weight to AAm is 0.3%,the concentration Na Cl is 0.4mol/L,the performance of the hydrogel toughened by macromolecule microspheres is the best,its elongation at break is 2211%,the fracture stress reaches the most 1232.41 KPa,performance Equivalent to double network hydrogel.This kind of gel toughening method based on the mechanism of elastic rubber particles toughening plastics,multifunctional macromolecule microspheres toughening hydrogel is an effective way.