Hydrogel の二, 三の性質の温度依存性に関する研究

抄録

The temperature dependence of physical properties was investigated for two different types of cross-linked hydrogel membranes, prepared from 2-hydroxyethyl methacrylate (HEMA) /methyl methacylate (MMA) copolymer system and from N-vinyl pyrrolidone (N-VP) /MMA copolymer system. The water content for the N-VP/MMA copolymer decreased in a temperature range from 0°C to 90°C, but for the HEMA/MMA copolymer it first decreased to approximately 55°C and then increased at higher temperatures. The change in oxygen permeability with rising temperature showed the same behavior as water content of hydrogels, because of permeation being due to water transport through swollen hydrogels. The retractive force of the N-VP/MMA copolymer on small strain below Λ=1.50 increased with rising temperature, on larger strain a retractive force minimum was found at approximately 70°C, where Λ=L/Lo; with L being the stretched gel strip length and Lo being the unstretched length. Under conditions of osmotic equilibrium, Warren and Prins observed a tensile load maximum at 55°C for a specimen held at constant length on HEMA gels. The results obtained in this study were contrary to their observation : a plot of the retractive force against temperature was found to show a minimum at approximately 55°C.
Hydrogels of varying water content were prepared to investigate the relationships between water content and oxygen permeability, between water content and tensile load and between water content and refractive index. Poly (HEMA), HEMA/MMA copolymer and N-VP/MMA copolymer were formulated to give hydrogels with water content from approxi-mately 23% to 82%.