Preparation And Properties Of Tannic Acid And Polyvinyl Alcohol Based Medical Adhesives

The good adhesion of marine mussels in humid environment is due to a mussel adhesion protein with strong adhesion ability secreted by mussels.Dopa in mussel adhesion protein plays a key role in the adhesion process,and the catechol group in its structure can connect with amine-containing molecules through Schiff base/Michael addition reaction after being oxidized to quinone group.It can also connect with mercaptan molecules through the Michael addition reaction to improve the adhesion property,so it still shows strong adhesion to the wet surface.However,dopamine is easily oxidized and difficult to graft onto other polymer segments.In this paper,tannic acid(TA)with the same high density phenolic hydroxyl structure is used to prepare TA-PVA medical adhesive,and the influence of different proportions on its properties is explored.In order to further improve the bond strength and antibacterial properties of the adhesive,TA-PVA-Ag~+adhesive and TA-PVA-CQAS adhesive are prepared by introducing silver ion(Ag~+)and chitosan quaternary ammonium salt(CQAS)respectively.The microstructure and crosslinking mechanism are studied by infrared spectroscopy(FTIR),~1H-nuclear magnetic resonance spectroscopy(~1H-NMR),scanning electron microscopy(SEM)and other methods,The influence of composition on the properties of adhesives are investigated and the internal mechanism are revealed.The hydrogen bonds are formed between TA and PVA in the TA-PVA medical adhesive.When TA:PVA mass ratio is 3:1,the adhesive strength is the highest,The bond strength is 179.2k Pa when bonding glass and the adhesive strength is 18.8 k Pa when bonding pig skin.TA-PVA adhesive has self-healing properties and good antibacterial properties.When TA:PVA mass ratio is 3:1,the antibacterial ratio of S.aureus and E.coli are 86.0%and 81.3%,respectively.And the clearance ratio is 94.8%at 18.3μg/m L TAVA3 concentration.In TA-PVA-Ag~+medical adhesive,the hydrogen bonds are formed between TA and PVA,in addition,the coordination bonds between phenol hydroxyl group of TA and Ag~+are formed.Therefore,TA-PVA-Ag~+medical adhesive has a double-layer network structure.When the mass ratio of Ag~+:TA is 0.03:3,the tensile strength and bond strength of TA-PVA-Ag~+medical adhesive are the highest.The bond strength of TA-PVA-Ag~+medical adhesive is 25.2 k Pa when bonding pig skin,which is 34.0%higher than that without Ag~+.The gel content,swelling ratio,initial water content and degradation ratio of TA-PVA-Ag~+medical adhesive slightly increase comparing with TA-PVA.TA-PVA-Ag~+medical adhesive has self-healing properties and good antibacterial and antioxidant properties.TA-PVA and TA-CQAS of constitute double hydrogen bond network structure in TA-PVA-CQAS medical adhesive.CQAS content has a great influence on the mechanical properties of TA-PVA-CQAS adhesives.With the increase of the CQAS content,the tensile strength and bonding strength of TA-PVA-CQAS adhesives increase first and then decrease.When the mass ratio of PVA:CQAS is 1:0.09,the tensile strength and bond strength of the adhesive reach the maximum.The bond strengths of bonding glass and pig skin are 310.0 k Pa and 23.6 k Pa,which are 73.0%and 25.5%higher than that of TA-PVA,respectively.Adding CQAS increases the gel content and swelling ratio of adhesives slightly,while decreases the degradation ratio.The addition of CQAS improves the antibacterial properties of the adhesive.When the mass ratio of PVA:CQAS is 1:0.09,the antibacterial ratios of S.aureus and E.coli are 91.1%and 90.3%.