Study On Toughning PVA-based Hydrogels With SiO₂ Particles

Hydrogels have been used as an alternative to articular cartilage due to their high water content,high toughness,and excellent mechanical properties.Cartilage and cartilage can lead to osteoarthritis due to injury or other causes.Osteoarthritis can cause damage to the entire joint if left untreated.Given the limited ability of articular cartilage to repair itself,cartilage replacement has become one of the most popular methods for treating cartilage injuries.To date,PVA hydrogels have been considered as an ideal candidate because of their excellent biocompatibility,flexibility,low coefficient of friction,and superhydrophilicity.Moreover,the porous structure inside PVA hydrogel is similar to articular cartilage.However,the mechanical properties of PVA hydrogels do not satisfy the bio-load bearing material.Thus,we need to improve the mechanical properties of PVA hydrogels urgently.In this dissertation,Si02 particles and PVA are the main lines.Firstly,SiO2 particles with different particle sizes were used to toughen PVA hydrogels in situ using sol-gel method.Secondly,through the sol-gel method,vinyl silica particles with different particle sizes were prepared.By adding the nano-filled material into the interpenetrating network hydrogel,the mechanical properties of the hydrogel were enhanced in various degrees.The main work is as follows:1:SiO2 particles with different particle diameters were generated in situ by sol-gel method.SiO2/PVA composite tough hydrogel with excellent comprehensive performance was successfully prepared by freeze-thaw technique.Through IR,ATR-IR and SEM,we analyzed the internal structure of the hydrogel and the crosslinking mechanism.Since MTMS and water are mutually soluble in any proportion,by adjusting the content of MTMS in the hydrogel,the hydrogel's mechanical properties can be changed to adapt to different needs.Through the analysis of the performance of Si02/PVA composite hydrogel,it is proved that compared with pure PVA hydrogel,the mechanical properties are greatly improved.The tensile strength of the composite hydrogel is 1.2MPa while the compressive strength is 38.2MPa.Also,the obtained hydrogel has low-swelling properties,which can meet the application requirements in the physiological environment.2:Using the sol-gel method,different particle sizes of vinyl hybrid silica particles were prepared.The PVA/AAm/vinyl Si02 hydrogels were prepared by combining free radical polymerization and freeze-thaw technology.By TEM,IR,it was confirmed that the synthesized vinyl silica particles are monodispersed and have a large number of c=c on the surface.Through the analysis of mechanical properties,it is proved that the hydrogel has good mechanical properties.The Tensile and compression strength can reach MPa level.The mechanical properties of the hydrogel can be improved and controlled by controlling the particle size and concentration of the added vinyl hybrid silica particles,such as:tensile modulus,tensile strength,elongation at break,etc.