Characterization of UV-curable Poly（ethylene glycol） Diacrylate Based Hydrogels

Poly（ethylene glycol） diacrylate/polyvinyl alcohoI（PEGDA/PVA） hydrogels were prepared from PEGDA and PVA as precurors by means of single UV radiation（UV ra.）, UV radiation followed by high energy electron beam irradiation（Irra.）, UV radiation followed by freeze-thawing（FT） or UV ra. and Irra. followed by FT, respectively. 2-Hydroxy-l-[4-（hydroxyethoxy）phenyl]-2-methyl-l-propanone（Irgacure 2959） was used as a photoinitiator. The effects of the various methods on the swelling and mechanical properties of the hydrogels were investigated. The results show that hydrogels made by UV ra. plus high energy electron beam irradiation followed by FT showed a higher crosslinking density and a larger tensile strength than those made by the other methods.

Mechanical and Adhesive Properties of Ploy（ethylene glycerol） Diacrylate Based Hydrogels Plasticized with PEG and Glycerol

Using polyethylene glycol（PEG） or glycerol as the plasticizer, we synthesized the hydrogels from poly（ethylene glycol） diacrylate（PEGDA）, polyvinylpyrrolidone（PVP） and poly（vinyl alcohol）（PVA） under UV radiation. The effects of different plasticizers on the mechanical properties and adhesion properties of the hydrogels were investigated. The results show that the plasticizer can improve the elongation and peeling force. The most pronotmced changes in the tensile property of the hydrogels are due to the addition of glycerol followed by PEG, the lower the plasticizer＇s molecular weight, the greater its effect. The maximum peeling force is 0.317 or 0.257 N with PEG or glycerol as plasticizer, respectively, and their adhesion properties are due to the formation of hydrogen bonds.