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
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
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
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
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
Authors:Barbara Bellich, Massimiliano Borgogna, Michela Cok, and Attilio Cesàro
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
Authors:László Janovák, János Varga, Lajos Kemény, and Imre Dékány
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.
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
Authors:Mohammad Fares, Adeeb El-faqeeh, Hasan Ghanem, Mohammad Osman, and Elfatih Hassan
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
Authors:M. Iijima, T. Hatakeyama, M. Takahashi, and H. Hatakeyama
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.