Thermal aging behavior of high performance poly(vinyl alcohol) hydrogel

The thermal aging behavior of poly(vinyl alcohol) (PVA) hydrogel was studied at four different temperatures of 40.℃, 50.℃, 60.℃ and 70.℃ in one year. The samples of PVA hydrogel were closely covered by plastic film. The changes of their chemical structures and physical properties during aging were measured through different measurable techniques including tensile testing, gel permeation chromatography (GPC), viscosity analysis, and Fourier transform infrared (FTIR) spectrum. The results showed that the molecular weight of PVA in hydrogel changed little with time and temperature. FTIR spectra of PVA in all the samples were similar to those of the original samples. The tensile strength of PVA hydrogel didn’t change until the 330^th days.