The pH-sensitive copolymer hydrogels were prepared with the monomers of acrylic acid and N-vinyl-2-pyrrolidone based on gamma radiation technique. The morphology of the hydrogels was monitored by using scanning electron microscope. The influence of absorbed dose, monomer composition and concentration on the swelling ratio (SR) of the hydrogels were investigated in detail. The effect of pH and temperature of the swelling medium on the swelling behavior of the hydrogels were also examined. The results show that the SR of the copolymer hydrogels decreases with the monomer concentration and absorbed dose increasing. The copolymer hydrogels show a better pH-sensitive behavior. In alkaline solution, the SR of the hydrogels is much higher than in acid solution.
In this study,hydrogels of P(NIPA-co-NVP)/clay were synthesized byγ-ray radiation.Different thermo-sensitive hydrogels were made under different experimental conditions such as dose,monomer ratio,and con- tent of clay.X-ray diffraction shows that the layer distance between Na-clays is changed from 1.6 to 2.7 nm because Na-clay pieces can be intercalated or exfoliated by HTMAB,and that between P(NIPA-co-NVP)/clay pieces is 3.4 nm. The swelling property tests show that the LCST of P(NIPA-co-NVP) is higher than PNIPA.With the increase of NVP content,LCST is higher.As the ratio of NIPA/NVP is 95/5,hydrogel shows the best swelling property and LCST is 37℃.LCST of P(NIPA-co-NVP)/clay hydrogel is not changed,but the strength and swelling properties are better.
SONG HongyanYANG MingchengZHU ChengshenHE SuqinGAO Ya
The pH-sensitive P(AA-co-NVP)/clay hydrogels were prepared with the monomers of acrylic acid(AA)and N-vinyl-2-pyrrolidone(NVP)based onγ-ray irradiation technique.The influence of pH values of buffer solutions and contents of clay and NVP on the equilibrium swelling ratio(SR)and compressive properties of the hydrogels was investigated in detail.The results of swelling property tests showed that,with the increase of clay content,the SR of hydrogels increases in the same buffer solution,and the SR of hydrog...
The pH-sensitive polyacrylic acid (PAA) hydrogels were synthesized by gamma-ray irradiation at an am- bient temperature. The influences of dose, monomer concentration, cross-linking agent content, pH, and ionic strength on the swelling ratio (SR) of the PAA hydrogels were investigated in detail. The results show that the SR of the hy- drogel decreases with an increase in the dose, monomer concentration, and cross-linking agent content. In alkaline so- lution, the SR of the hydrogels is much higher than that in acid solution. Also, the ionic strength can influence the SR of the hydrogels. The more the concentration, the lower the
