A New Sorbent Chemically Cross-linked Highly Swollen Copolymeric Hydrogels for Dye Uptake

Water uptake and the sorption properties of polyelectrolyte hydrogels made by the polymerization of acrylamide (AAm) with maleic acid (MA) were investigated as a function of composition to find materials with swelling and dye sorption properties. Highly swollen acrylamide/maleic acid (AAm/MA) hydrogels were prepared by free radical solution polymerization in aqueous solutions of AAm with MA as comonomer and two multifunctional cross-linkers such as trimethylolpropane triacrylate (TMPTA) and 1,4-butanediol dimethacrylate (BDMA). Swelling experiments were performed in water at 25°C, gravimetrically. Chemically cross-linked AAm/MA hydrogels were used in experiments on sorption of water-soluble monovalent cationic dyes such as “Nil blue” (NB) and “Methyl violet (MV)”. Weight-swelling ratio values of AAm/MA hydrogels were calculated range 8.88–61.46. Some swelling kinetic parameters were found. Diffusion behavior of water and water sorption rate constant were investigated. Water diffusion into hydrogels was found to be non-Fickian in character. For sorption of cationic dyes, NB and MV into AAm/MA hydrogels were studied by batch sorption technique at 25°C. AAm/MA hydrogels in the dye solutions showed coloration. However, the AAm hydrogel did not show sorption of any dye from solution. The amount of the dye sorbed per unit mass of AAm/MA hydrogels was investigated.     

Equilibrium Swelling Characterization and Dye Uptake Studies of Acrylamide-co-Methylenesuccinic Acid Hydrogels and Semi-IPNs with PEG

A novel semi-interpenetrating network hydrogel, composed of acrylamide with methylenesuccinic acid as comonomer, with poly (ethylene glycol) and trimethylolpropane triacrylate was prepared. Highly swollen hydrogels were synthesized by free radical polymerization. Swelling experiments were performed in water and dye solutions at 25°C. The hydrogels were used in experiments on sorption of Basic Blue 12. Water and Basic Blue 12 diffusion into hydrogels was found to be non-Fickian in character. For sorption of BB 12 into the hydrogels was studied by batch sorption technique at 25°C. The adsorption capacity, removal effiency and partition coefficient of the hydrogels was investigated.     

Swelling Characterization and Adsorptive Features of Acrylamide/Itaconic Acid Hydrogels and Semi-IPNs for Uranyl Ions

A novel semi-interpenetrating network (semi-IPNs) hydrogel, composed of acrylamide (AAm) with itaconic acid (ITA) as co-monomer, with poly (ethylene glycol)(PEG) and trimethylolpropane triacrylate (TMPTA) was prepared. Hydrogels and semi-IPNs were synthesized by free radical solution polymerization. Swelling experiments were performed in water and aqueous solutions of uranyl acetate. Diffusion behavior was investigated and their diffusion into hydrogels was found to be non-Fickian in character. Sorption of uranyl ion onto the polymeric system was studied by a batch sorption technique at 25°C. The sorption capacity, removal effiency and partition coefficient of the hydrogels were investigated.     

分光光度法测定丙烯酸丁酯中4-甲氧基酚含量

以亚硝酸钠为显色剂,测定丙烯酸丁酯中4-甲氧基酚含量。考察了测定条件:在酸性介质中,最大波长位于420 nm,4-甲氧基酚浓度在0~800μg范围内符合比耳定律,线性关系较好。实验结果显示,该方法适用于丙烯酸丁酯中4—甲氧基酚含量的测定,结果满意。     

Superabsorbent polymeric materials X: Effect of degree of neutralization on swelling behavior of crosslinked poly(sodium acrylate) in aqueous salt solutions

A series of xerogels based on different degrees of neutralizations (DN) of acrylic acid (AA) and N,N-methylene-bis-acrylamide (NMBA) were prepared by inverse suspension polymerization. The influence of the DN values of AA on water absorbency and swelling behavior for these highly absorbent polymers in deionized water and various saline solutions were investigated. Results indicate that the equilibrium-water absorbency (Q_eq) increases with an increase in the DN of AA until the DN value reaches 95% and then decreases at 100% of the DN value. However, the initial absorption rate for these gels decreases with an increase in the DN value of AA in both deionized water and 0.9 wt% NaCl solution. The adsorption of copper ions by these gels was also investigated.     

Solubility of Sodium Phenytoin in Ethanol + Water Mixtures at Various Temperatures

The solubility of sodium phenytoin in binary mixtures of ethanol + water at 298.2, 303.2, 308.2, and 313.2 K was measured. The solubility was increased by addition of ethanol, reached a maximum value at 0.50 mass fraction of ethanol, and then decreased with further increase of ethanol. At all temperatures, the solubility of the solute in neat water was greater than that of neat ethanol. The Jouyban–Acree model and its combined version with the van't Hoff equation were used to predict the reported solubilities, resulting in a mean relative deviation of 12.7 and 13.7%, respectively.     

反相悬浮法合成耐盐性超强吸水剂

以甲氧基聚氧乙烯单甲基丙烯酸酯大单体(PEO-MA),丙烯酸和丙烯酰胺为原料,十八烷基磷酸单酯为分散剂,环己烷为分散介质,经反相悬浮聚合合成了甲氧基聚氧乙烯单甲基丙烯酸酯-丙烯酸-丙烯酰胺类超强吸水性树脂。最佳工艺条件为反应温度75℃,单体水溶液浓度为23%,引发剂用量为0.23%(占AA、AM的总质量),交联剂用量为0.37‰(占AA、AM的总质量),大单体用量占单体总质量的39%。制得的树脂吸去离子水可达930ml/g,吸0.9%的NaCl溶液为94ml/g。最佳工艺条件下得到的树脂8min内即可吸水460倍。其吸水前3min为CaseⅡ扩散,3～50min为Fickian扩散。