Preparation And Properties Of Polyvinyl-pyrrolidone And Its Composite Hydrogel

Polyvinyl pyrrolidone is a polymer compound formed by the polymerization of monomer vinyl,which has many excellent properties such as high solubility,biocompatibility,low cytotoxicity,etc.PVP and different substances are physically or chemically reacted to produce hydrogels.Most of the composite hydrogels have excellent properties and can be applied in a variety of fields.However,both physical and chemical crosslinking methods have their own defects,and PVP is mostly introduced as an adjuvant,which limits the scope of application of PVP to a certain extent.By studying the structure of PVP itself,this paper prepared simple,green and pollution-free PVP hydrogels and PVP based composite hydrogels without introducing any crosslinking agent and organic solvent.The main content is divided into the following two aspects:Part one: Using deionized water as solvent,the lactam bond was heated in the presence of sodium hydroxide to break two active sites,and then the intermolecular crosslinking occurred to produce macromolecular hydrogels.The influence of reaction temperature and alkali concentration on hydrogel performance was discussed in the preparation process.By comparing the infrared spectrum,it was found that the absorption peak at 1660cm-1 shifted to the left,and the reduction of the absorption peak intensity indicated that the lactam ring was severed and recombined to confirm the crosslinking of PVP.The research showed that when the reaction temperature was 70 ℃ and the concentration of sodium hydroxide was 2M,The PVP hydrogel has the best performance,and the tensile property of the hydrogel is the best.The elongation at break is 246.05%,the fracture stress is 24.70 k Pa and the elastic modulus is 1.6932 k Pa.Bovine serum protein(BSA)was used as the drug model to explore the drug loading capacity of hydrogel.Through the analysis of experimental data,the optimal drug loading capacity(DL)was24.77%,the encapsulation rate(EN)was 8.15%,and the drug release rate was up to64.71%.Part two: On the basis of this reaction,polyethylene glycol(PEG)and dextran(DEX)were introduced to prepare a PVP based complex hydrogel.The hydroxyl groups contained in polyethylene glycol and dextran could form hydrogen bonds with the carbonyl group generated by the fracture of the PVP lactam ring to construct a complex hydrogel network.The introduction of PEG and DEX was confirmed by infrared.The tensile test of hydrogel showed that PVP/PEG was superior to PVP/DEX in mechanical properties.In this case,the fracture stress was 12.30 k Pa,the elongation at break was 200.50%,and the elastic modulus was 1.7628 k Pa.However,on the contrary,the composite hydrogel PVP/DEX showed good drug release performance,with the maximum drug loading capacity of 39.89%,the encapsulation rate of 12%,and the maximum drug release capacity of 75.45%.To sum up,in this paper,PVP hydrogels and PVP based composite hydrogels were prepared in a simple,fast,green and pollution-free way without introducing any crosslinking agent and organic solvent,and their properties were tested.It was found that the hydrogels have a wide range of applications in the field of biomedicine.