Preparation And Characterization Of UV-curable Poly(Ethylene Glycol) Diacrylate Based Hydrogels

Hydrogels as soft and wet materials consisting of three-dimensional(3D) cross-linked networks and a large amount of water have been applied widely in industry, agriculture and biomedical engineering. Hydrogels can be fabricated by virtue of many methods, including radiating, thermal annealing, freeze thawing(FT), and chemical crosslinking based on agents to generate the physically or chemically cross-linked hydrophilic polymer networks. Among these methods, UV radiation is widely used because of the reduction of solvent consumption and emissions. The raw materials for the formation of hydrogels by UV radiation are mainly acrylic amide(AM), acrylic acid(AA) and their derivatives, but the small molecule residues in the process of reaction have limited their application in biology. Hydrophilic poly(ethylene glycol) diacrylate(PEGDA) macromers, which possess ―C=C― bonds at their chain ends, form hydrogels by photo-crosslink, and they have a better biocompatibility. However, PEGDA hydrogels prepared by UV radiation have a poor mechanical strength. In this paper, PEGDA hydrogels were firstly prepared, and were subsequently adding different component to fabricate composite hydrogels with high mechanical strength and better adhesive properties.Detailed contents are listed as follows:1. PEGDA-based hydrogels were prepared in the presence of polyvinyl alcohol(PVA) as a second component to enhance the mechanical properties of hydrogels, and the effects of various methods[e. g., UV radiation(UV ra.), high energy electron beam irradiation(Irra.) and freeze-thawing(FT)] on the swelling ability and mechanical properties of PEGDA based hydrogels were investigated. It shows that adding PVA into the PEGDA-based hydrogels is helpful to improving the tensile properties. The high energy electron beam irradiation can increase the crosslinking density and tensile strength of the hydrogels. The hydrogel prepared by means of UV radiation plus high energy electron beam irradiation followed by freeze thawing has a tighter network structure and a larger tensile strength compared with those prepared by the other methods.2. We prepare the hydrogels using PEGDA, PVA and polyvinylpyrrolidone(PVP) by means of UV radiation, polyethylene glycol(PEG) or glycerol as the plasticizers. The effects of different plasticizers on the mechanical properties and adhesion properties of hydrogels were investigated. The results show that the gel fraction decreases by incorporating PEG or glycerol, which acts not only as plasticizer but also to modify the gel fraction. PEGDA-based hydrogels have also shown good elongation at break markedly modified by glycerol followed by PEG. Plasticizer inclusion caused a reduction in tensile strength, an increase in its strain at failure and a significant increment in peeling force.3. We study the effects of different radiation intensity and UV radiation time on the compression properties and adhesion properties of PEGDA/PVA/ws-CTS hydrogels. The final selection of the radiation intensity is 55%, the radiation time is 20 minutes to prepare hydrogels have a relatively better compression strength and adhesion.