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semi-IPN Hydrogels (semi-ipn + hydrogel)
Selected AbstractsCarrageenan- g -poly(acrylamide)/poly(vinylsulfonic acid, sodium salt) as a novel semi-IPN hydrogel: Synthesis, characterization, and swelling behaviorPOLYMER ENGINEERING & SCIENCE, Issue 9 2007Ali Pourjavadi A semi-interpenetrating polymer network (semi-IPN) hydrogel based on kappa-carrageenan (,C) and poly (vinylsulfonic acid, sodium salt) (PVSA) was prepared by graft copolymerization of acrylamide (AAm) using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. FTIR spectroscopy was used for confirming the structure of the final product. It was found that the chemical composition of the Semi-IPN hydrogel is equal to the initial homopolymers and monomer feed compositions. The swelling capacity of the hydrogel was shown to be affected by the MBA, APS, and AAm concentration as well as ,C/PVSA weight ratio. The swelling behavior of the hydrogel was also investigated in various pHs and salt solutions. Since the highly swelling biopolymer-based hydrogel exhibits low salt-sensitivity, it may be referred to as an anti-salt superabsorbent hydrogel. The swelling kinetics of the superabsorbent hydrogels was studied as well. POLYM. ENG. SCI., 47:1388,1395, 2007. © 2007 Society of Plastics Engineers [source] The controlled release behavior and pH- and thermo-sensitivity of alginate/poly(vinyl alcohol) blended hydrogelsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2009Win-Chun Jao Abstract Poly(vinyl alcohol) (PVA) was blended with sodium alginate (Alg) in various ratios and crosslinked with calcium chloride and made into hydrogel membranes. The dependence of the swelling behavior of these Alg-Ca/PVA hydrogels on pH was investigated. The temperature-dependent swelling behavior of the semi-interpenetrating network (semi-IPN) hydrogels was examined at temperatures from 2 to 45°C and the enthalpy of mixing (,Hmix) was determined at various temperatures. The molecular structure of the hydrogels was studied by infrared spectroscopy and their water structure in the semi-IPN hydrogels was measured by differential scanning calorimetry (DSC). The influence of Ca2+ content on the network structure of Alg-Ca/PVA hydrogels was investigated in terms of the compressive elastic modulus, effective crosslinking density, and the polymer,solvent interaction parameter based on the Flory theory. The loading of alizarin red S (ARS) followed the Langmuir isotherm mechanism and the release kinetics of ARS from the Alg-Ca/PVA hydrogels followed the Fickian diffusion mechanism. Copyright © 2008 John Wiley & Sons, Ltd. [source] Synthesis and characterization of ,-carrageenan/poly(N,N -diethylacrylamide) semi-interpenetrating polymer network hydrogels with rapid response to temperaturePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11 2008Jun Chen Abstract In this study, a novel classical thermo- and salt-sensitive semi-interpenetrating polymer network (semi-IPN) hydrogel composed of poly(N,N -diethylacrylamide) (PDEAm) and ,-carrageenan (KC) was synthesized by free radical polymerization. The structure of the hydrogels was studied by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR and SEM revealed that the semi-IPN hydrogels possessed the structure of H-bonds and larger number of pores in the network. Compared to the PDEAm hydrogel, the prepared semi-IPN hydrogels exhibited a much faster response rate to temperature changes and had larger equilibrium swelling ratios at temperatures below the lower critical solution temperature (LCST). The salt-sensitive behavior of the semi-IPN hydrogels was dependent on the content of KC. In addition, during the reswelling process, semi-IPN hydrogels showed a non-sigmoidal swelling pattern. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||