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nanotechnology, Hydrogel carriers in wastewater treatment , Progress in Colloid and Polymer Science , Vol. 135 , 2008 , pp. 209 – 217 . [15] Sándor D

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Journal of Thermal Analysis and Calorimetry
Authors: Taís Vanessa Gabbay Alves, Eraldo José Madureira Tavares, Fauze Ahmad Aouada, Charles Alberto Brito Negrão, Marcos Enê Chaves Oliveira, Anivaldo Pereira Duarte Júnior, Carlos Emmerson Ferreira da Costa, José Otávio Carréra Silva Júnior, and Roseane Maria Ribeiro Costa

Introduction Hydrogels are gels that can absorb large quantities of water. They are not deformed and are constituted by polymeric material networks that form three-dimensional structures which are rich in polar groups. Because

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Hoffman A. Hydrogels for biomedical applications, Advanced Drug Delivery Reviews , Vol. 43, 2002, pp. 3–12. Hoffman A. Hydrogels for

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Journal of Thermal Analysis and Calorimetry
Authors: A. Kyritsis, A. Spanoudaki, C. Pandis, L. Hartmann, R. Pelster, N. Shinyashiki, J. C. Rodríguez Hernández, J. L. Gómez Ribelles, M. Monleón Pradas, and P. Pissis

Introduction Polymer hydrogels absorb large amounts of water, owing to the presence of hydrophilic groups in their structure, and preserve at the same time their integrity, because of being cross-linked. Good biocompatibility

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Interventional Medicine and Applied Science
Authors: Krisztina Nagy, Orsolya Láng, Júlia Láng, Katalin Perczel-Kovách, Szabolcs Gyulai-Gaál, Kristóf Kádár, László Kőhidai, and Gábor Varga

]. Intensive research to find structures for biomedical application found that hydrogels are the most promising scaffolds [ 4 – 6 ]. Hydrogels are cross-linked, three-dimensional hydrophilic polymer networks that are insoluble in water but can absorb large

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Water evaporation from gel beads

A calorimetric approach to hydrogel matrix release properties

Journal of Thermal Analysis and Calorimetry
Authors: Barbara Bellich, Massimiliano Borgogna, Michela Cok, and Attilio Cesàro

Introduction Hydrogels are characterized by particular properties which make them ideal candidates for applications in several fields, such as drug delivery, biomedicine, and functional foods. The common property underlying the

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Abstract  

We studied the effect of variations in the composition of the 3D polymer matrix on the water adsorption properties of poly(N-isopropylacrylamide-co-acrylamide) [abbreviated as poly(NIPAAm-co-AAm)]-based gels containing fillers of diverse hydrophilicities (Na-montmorillonite and hydrophobized montmorillonite). The hydrophilicity of the polymer matrix was modified by varying the ratio of the initial monomers, since acrylamide (AAm) is hydrophilic, whereas N-isopropylacrylamide (NIPAAm) is relatively hydrophobic. Filler content was varied in the range of 1–25 wt%. The water content of polymers, fillers and composites, a parameter determined by their different hydrophilicities was characterized by gravimetry and/or thermoanalytical methods (TG, DSC). The water content of the samples was found to be controllable by varying the hydrophilicity of the polymer matrix and/or the amount and hydrophilicity of the fillers added. Swelling of the relatively hydrophobic poly(NIPAAm) can be increased by the addition of hydrophobic fillers, whereas that of the hydrophilic poly(AAm) can be enhanced by the addition of hydrophilic fillers. The effect of changes in composition on the desorption enthalpies of the samples was determined. The water content of the copolymer increases with increasing the ratio of the hydrophilic monomer, which is due to an increase in the so-called free water content. In the case of the hydrophobic poly(NIPAAm) it is primarily hydrophobic association interactions that dominate the interaction between the polymer matrix and the lamellae of the filler, whereas in the case of the hydrophilic poly(AAm) hydrophilic interactions are dominant.

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Journal of Thermal Analysis and Calorimetry
Authors: Mayté Paredes Zaldivar, Norma Galego Fernández, Cristina Gastón Peña, Manuel Rapado Paneque, and Sonia Altanés Valentín

]. The semi-IPNs represent a system in which only one of the polymer networks is covalently crosslinked (s-IPNs) [ 2 , 4 – 6 ]. Some of these IPNs have hydrogels properties. They may have the same applications as conventional hydrogels but with the

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Journal of Thermal Analysis and Calorimetry
Authors: Mohammad Fares, Adeeb El-faqeeh, Hasan Ghanem, Mohammad Osman, and Elfatih Hassan

Introduction The hydrogels of modified natural polymers is finding an increasingly interest due to its noticeable applications such as thermoresponsive polymers [ 1 , 2 ]. Furthermore, its applicability is finding wide

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Abstract  

Application of thermomechanometry to the measurement of hydrogels containing a large amount of water was carried out by static and dynamic methods. A thermomechanical analyzer (TMA) equipped with a quartz compression probe immersed in water was used. Polysaccharide hydrogels containing ca 98% water were measured. Creep of hydrogels in water was analyzed in a stress range from 1.04⋅103 to 5.2⋅103 Pa and loading rate from 0.3⋅103 to 3.0⋅103 Pa min−1.Stress relaxation was measured in compressed ratio range from 0.02 to 0.45 m m−1 and in compressing rate was 0.09 to 0.15 m m−1 min−1. Dynamic viscoelasticity was measured by TMA when dynamic Young’s modulus which was larger than 1⋅104 Pa in frequencies ranging from 0.02~0.2 Hz.

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