Modified chitosan 4. Superabsorbent hydrogels from poly(acrylic acid-co-acrylamide) grafted chitosan with salt- and pH-responsiveness properties

Mahdavinia, Gholam Reza; Pourjavadi, Ali; Hosseinzadeh, Hossein; Zohuriaan, M.J

doi:10.1016/j.eurpolymj.2004.01.039

Cited by 502 publications

(254 citation statements)

References 20 publications

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“…The very intense characteristic band at 1560 cm −1 is due to the C(O asymmetric stretching of the carboxylate anion from poly(AA) grafted onto M3 and M4 chitosan membranes. This is reconfirmed by other sharp peak at 1405 cm −1 , which is related to the symmetric stretching mode of the carboxylate anion (Hu et al, 2002;Mahdavinia et al, 2004). The salt form of the free carboxylic group is expected since the membranes were neutralized with sodium hydroxide solution to remove them from the plates.…”

Section: Resultsmentioning

confidence: 70%

Synthesis and characterization of membranes obtained by graft copolymerization of 2-hydroxyethyl methacrylate and acrylic acid onto chitosan

Santos

Coelho

Ferreira

et al. 2006

International Journal of Pharmaceutics

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Chitosan based membranes to be applied on wound healing as topical drug delivery systems were developed by graft copolymerization of acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) onto chitosan using cerium ammonium nitrate as chemical initiator. Evidence for graft copolymerization of the vinyl monomers onto chitosan was obtained by FTIR and DMTA. Swelling degree, cytotoxicity, thrombogenicity and haemolytic activity of these membranes were evaluated. Chitosan-graft-AA-graft-HEMA showed to be the best matrix for drug delivery systems than chitosan-graft-AA because it retains good swelling properties, but the content in HEMA has improved cytocompatibility, hemocompatibility and thrombogenic character.

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Section: Resultsmentioning

confidence: 70%

Synthesis and characterization of membranes obtained by graft copolymerization of 2-hydroxyethyl methacrylate and acrylic acid onto chitosan

Santos

Coelho

Ferreira

et al. 2006

International Journal of Pharmaceutics

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“…Recently, attention has been focused on employing gelatin substrate to produce hydrogels with a specific response to a biological environment [17][18][19][20][21]. Therefore, following a continuous research on synthesis of natural-based superabsorbent hydrogels [22][23][24][25], in this paper we attempted the synthesis of a novel gelatin-based superabsorbing polymer. The swelling behavior in distilled water and various saline and pH solutions was investigated as well.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and absorbency of gelatin-graft-poly(sodium acrylate-co-acrylamide) superabsorbent hydrogel with saltand pH-responsiveness properties

Pourjavadi¹,

Sadeghi²,

Hashemi³

et al. 2006

E-Polymers

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Abstract:In this article, we synthesize a novel gelatin-based superabsorbent hydrogel via graft copolymerization of mixtures of acrylic acid (AA) and acrylamide (AAm) onto gelatin backbones. The polymerization reaction was carried out in an aqueous medium and in the presence of ammonium persulfate (APS) as an initiator and N,N'-methylene bisacrylamide (MBA) as a crosslinker. The hydrogel structures were confirmed by FTIR spectroscopy. The effect of grafting variables, i.e. concentration of MBA and APS, AA/AAm weight ratio, and reaction time and temperature, was systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The swelling behavior of these absorbent polymers was also investigated in various salt solutions. Results indicated that the swelling capacity decreased with an increase in the ionic strength of the swelling medium. Furthermore, the swelling of superabsorbing hydrogels was examined in solutions with pH values ranging between 1.0 and 13.0. It showed a reversible pH-responsive behavior at pHs 2.0 and 7.0. This on-off switching behavior makes the synthesized hydrogels an excellent candidate for controlled delivery of bioactive agents. Finally, the swelling kinetics of the synthesized hydrogels with various particle sizes was preliminarily investigated.

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“…Their highly crosslinked structure resulted in a marked decrease in the swelling ratio due to the reduction in the free volume within the hydrogel network. 36,37 Interestingly, the equilibrium swelling values did not seem to depend on the type of crosslinker used. Thus, the experimental data on equilibrium swelling exponentially decayed as the percentage of crosslinker increased in the experimental range in both cases.…”

Section: Resultsmentioning

confidence: 94%

Swelling control in thermo-responsive hydrogels based on 2-(2-methoxyethoxy)ethyl methacrylate by crosslinking and copolymerization with N-isopropylacrylamide

García-García

Liras

Quijada‐Garrido

et al. 2011

Polym J

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Two different strategies were used to modulate the swelling capacity of thermo-responsive hydrogels based on 2-(2-methoxyethoxy)ethyl methacrylate (MEO 2 MA) in water. In the first approach, several poly(MEO 2 MA) hydrogels were synthesized using different proportions of a conventional crosslinker, as tetra(ethylene glycol) dimethacrylate and a non-conventional inorganic crosslinker, as polyhedral oligomeric silsesquioxane (POSS) functionalized with eight methacrylic groups (POSS-meth 8 ). The experiments showed that the equilibrium swelling and the volume transition temperature (VTT) could be tuned by varying the crosslinker degree, regardless of the type of crosslinker. In the second approach, several poly (MEO 2 MA-co-N-iPAAm) hydrogels were prepared for the very first time, because N-isopropylacrylamide (N-iPAAm) is also a thermo-responsive component that increases the swelling capacity of the hydrogel in water. In addition, the VTT and the glass transition temperature of these new copolymer hydrogels could also be tuned by varying the monomeric composition. Polymer Journal (2011) 43, 887-892; doi:10.1038/pj.2011.83; published online 31 August 2011Keywords: 2-(2-methoxyethoxy)ethyl methacrylate; N-isopropylacrylamide; polyhedral oligomeric silsesquioxane; tetra(ethylene glycol) dimethacrylate; thermo-responsive hydrogels; volume transition temperature INTRODUCTION Thermo-responsive hydrogels undergo relatively large and abrupt volume changes in response to temperature. 1-3 Among these materials, N-isopropylacrylamide-based (N-iPAAm) hydrogels are the most studied 4,5 because poly(N-iPAAm) shows a well-defined lower critical solution temperature in water at around 31-34 1C, 6-8 which is close to body temperature. Thus, such stimuli-sensitive hydrogels have been intensively studied with respect to drug delivery 9,10 and other biomedical applications. [11][12][13][14][15][16][17] Recently, hydrogels based on oligo(ethylene glycol) side chains methacrylic monomers, 18-22 such as 2-(2-methoxyethoxy)ethyl methacrylate (MEO 2 MA), were highlighted as a successful alternative to poly(N-iPAAm)-based hydrogels because of the advantages of a controllable lower critical solution temperature, 23,24 high biocompatibility/ low cytotoxicity 25,26 and facile polymerization by both the free radical and the anionic polymerization mechanisms. 27 The previous investigations on MEO 2 MA-based hydrogels were mainly focused on controlling the thermo-responsive behavior for biomedical applications. For instance, they have been synthesized by controlled radical polymerization techniques, such as atom transfer radical polymerization, to create more homogeneous networks. 28 In other cases, they have been copolymerized with ionic monomers to obtain additional pH responsiveness. 20,22

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Modified chitosan 4. Superabsorbent hydrogels from poly(acrylic acid-co-acrylamide) grafted chitosan with salt- and pH-responsiveness properties

Cited by 502 publications

References 20 publications

Synthesis and characterization of membranes obtained by graft copolymerization of 2-hydroxyethyl methacrylate and acrylic acid onto chitosan

Synthesis and characterization of membranes obtained by graft copolymerization of 2-hydroxyethyl methacrylate and acrylic acid onto chitosan

Synthesis and absorbency of gelatin-graft-poly(sodium acrylate-co-acrylamide) superabsorbent hydrogel with saltand pH-responsiveness properties

Swelling control in thermo-responsive hydrogels based on 2-(2-methoxyethoxy)ethyl methacrylate by crosslinking and copolymerization with N-isopropylacrylamide

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