scholarly journals Synthesis and rheology of thermoreversible polyurethane hydrogels

2012 ◽  
Vol 10 (6) ◽  
pp. 1859-1866 ◽  
Author(s):  
Luiza Gradinaru ◽  
Constantin Ciobanu ◽  
Stelian Vlad ◽  
Maria Bercea ◽  
Marcel Popa
Keyword(s):  
Ethylene Oxide ◽  
Sol Gel ◽  
Gelation Point ◽  
Wetting Properties ◽  
Weight Concentration ◽  
Poly Ethylene Oxide ◽  
Ft Ir ◽  
Poly Ethylene ◽  
Poly Propylene ◽  
Self Aggregation

AbstractPolyurethanes based on poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer, succinic or citric acid, and ethyl ester L-lysine diisocyanate were synthesized and characterized by FT-IR and GPC. Wetting properties were evaluated by contact angle determinations. The critical micelle concentration was determined from surface tension measurements. Their abillity to undergo self-aggregation and temperature induced gelation was investigated through dynamic oscillatory measurements. The gelation point, sol-gel transitions, and gel structure are influenced by polymer structure, composition, molecular weight, concentration, and heating rate.

Adsorption of Zn(II) from Aqueous Solutions by Thiol-Functionalized MCM-48

2011 ◽  
Vol 413 ◽  
pp. 148-153 ◽  
Author(s):  
Xue Na Hu ◽  
Ya Han ◽  
Jia Yan Li ◽  
Jun Yan Wu ◽  
Jian Rong Chen ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Pluronic P123 ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Poly Ethylene Oxide ◽  
Ft Ir ◽  
Poly Ethylene ◽  
Poly Propylene

Thiol-functionalized MCM-48 (SH-MCM-48) was synthesized by co-condensation method, with co-templates of cetyltrimethylammonium bromide (CTAB) and nonionic poly (ethylene oxide)–poly (propylene oxide)–poly (ethylene oxide) triblock copolymer (Pluronic P123). The resulting material was characterized by XRD and FT-IR spectrum. The potential of SH-MCM-48 for adsorption Zn (II) from aqueous solution was examined. Batch adsorption studies were carried out to investigate the effect of experimental parameters including pH, metal ions concentration and adsorption time. The maximum adsorption capacities of Zn (II) onto SH-MCM-48 were 30.12, 34.01 and 38.02 mg g-1 at the temperature of 303, 313 and 323K, respectively. The adsorption kinetics data were found to follow the pseudo-second-order kinetic model, and adsorption isotherms were fitted well with Langmuir and Freundlich models. Moreover, the adsorption thermodynamic parameters (△G0, △H0 and △S0) were measured, and indicated that the adsorption was an exothermic and spontaneous process.

Effect of Al Ions on Adsorption Efficiency of Mesoporous Organosilica for Water Treatment

2011 ◽  
Vol 415-417 ◽  
pp. 2024-2031
Author(s):  
Hanafi Ani Mohd ◽  
Maziati Akmal Mohd Hatta ◽  
Raihan Othman
Keyword(s):  
Water Treatment ◽  
Ethylene Oxide ◽  
Adsorption Capacity ◽  
Sol Gel ◽  
Adsorption Efficiency ◽  
Water Treatment Process ◽  
Mesoporous Organosilica ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Poly Propylene

Porous organosilica is a promising material to be applied in water treatment due to high adsorption capacity of contaminants. Sol-gel method was used to fabricate mesoporous organosilioca from triblock copolymers, poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) as the template and tetraethylorthosilicate as silicate source. The organosilica is doped with Al powder and Al2SO3 in order to evaluate the effect of ions on their adsorption capacity. It was demonstrated that the adsorption capacity is proportional to Al concentration, and inversely proportional to porosity. Metallic compound doped in organosilica enhances the remediation process and optimize the water treatment process. Moreover, impregnation the samples into cellulosic sponge improves the adsorption efficiency by 25%.

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