Study On The Preparation And Performance Of PVA-based High-strength And High-toughness Composite Hydrogel

The unique swelling properties,environmental response and cell-like matrix characteristics of hydrogels make it widely used in many fields,such as tissue engineering,wastewater treatment,drug delivery and flexible electrodes.Some application fields put forward higher requirements on the mechanical properties of the gel,but most of the hydrogels have a significant decrease in their mechanical properties after swelling in water,which makes them unable to meet the requirements for use.Therefore,the high strength and toughness of hydrogels is one of the problems that need to be solved urgently.Polyvinyl alcohol(PVA)has good water solubility and biocompatibility and is currently one of the most widely used synthetic polymer materials.The molecular chain contains a large number of hydroxyl groups,which makes it possible to achieve high strength,toughness and functionalization.In this research,PVA is used as the main matrix,through different treatment methods to make it have high strength and toughness,and on this basis,the PVA composite hydrogel with additional functional characteristics is developed to realize its application in different fields.The specific research content and main results are as follows:(1)The hydrogel is prepared with PVA as the main substrate,and high-performance hydrogels are obtained by changing different processing methods,molecular weights,mass fractions and solvents,and the influence of these factors on the mechanical properties of PVA hydrogels is studied.The results show that high reaction temperature is beneficial to improve the mechanical strength of PVA hydrogel,freeze-thaw treatment can effectively improve the toughness of hydrogel,and annealing treatment can further improve the mechanical properties of PVA hydrogel.Combining room temperature reaction and freeze-thaw treatment can achieve the best comprehensive mechanical effect.Secondly,the mechanical properties of PVA hydrogels increase first and then decrease with the increase of molecular weight or mass fraction.By changing the reaction solvent,the mechanical and other functional properties of the PVA hydrogel can be effectively adjusted.As a result,the influence of various factors on the mechanical properties of PVA hydrogels was obtained,and high-strength PVA hydrogels were successfully prepared.(2)Using high-strength PVA as a matrix,adding polyhydroxyethyl methacrylate(PHEMA)components to construct a double-network composite hydrogel,and further adding fumed silica to etch holes to obtain a PVA/PHEMA dual-network hydrogel filter membrane.The results show that the hydrogel filter membrane has good mechanical properties and filtration characteristics,and it can achieve high-efficiency interception of the dye ions in the printing and dyeing wastewater,thereby being applied in the field of wastewater treatment.(3)The PVA/PHEMA composite hydrogel with microsphere structure was prepared by adjusting the content of crosslinking agent and initiator.The results show that the drug-loaded gel has excellent drug loading performance while maintaining good mechanical properties.The drugloaded microsphere gel has excellent antibacterial effect on Staphylococcus aureus,and it has great application potential in the field of drug release.