Hydrogels based on modified chitosan, 1. Synthesis and swelling behavior of poly(acrylic acid) grafted chitosan

Yazdani‐Pedram, Mehrdad; Retuert, Jaime; Quijada, Raúl

doi:10.1002/1521-3935(20000601)201:9<923::aid-macp923>3.0.co;2-w

Cited by 124 publications

(60 citation statements)

References 30 publications

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“…Recently, broad interests have been raised on the chemical modification via grafting synthetic polymers onto chitosan, [7][8][9][10][11][12][13] because chitosan could show much improved bioactivities such as antibacterial and antioxidant activities. But not all grafting copolymers have ideal properties, for instant solubility.…”

supporting

confidence: 85%

Synthesis, Characterization and Drug Release Behavior of pH‐Responsive O‐carboxymethyl Chitosan‐graft‐poly(N‐vinylpyrrolidone) Hydrogel Beads

Liu

et al. 2009

Adv Eng Mater

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In this work, the carboxymethyl chitosan (CMCTS) grafted poly(N‐vinylpyrrolidone) (PVP) copolymers were synthesized. The hydrogel beads containing VB2 were prepared from the copolymers by an ionic crosslinked. The experimental results shown that VB2 drug release rate from those beads decreased with the increasing grafting percentage, crosslinker concentration and pH value of the medium. Besides, the beads have the better control ability for releasing of model drug than CMCTS does.

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supporting

confidence: 85%

Synthesis, Characterization and Drug Release Behavior of pH‐Responsive O‐carboxymethyl Chitosan‐graft‐poly(N‐vinylpyrrolidone) Hydrogel Beads

Liu

et al. 2009

Adv Eng Mater

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“…The optimum reaction conditions to obtain maximum water absorbency (275 g/g) were found to be: MBA 0.043 mol/L, AA 0.49 mol/L, AAm 0.13 mol/L, APS 0.02 mol/L, reaction temperature 60 o C, and reaction time 180 min. The superabsorbent hydrogels exhibited high sensitivity to pH, so that, several swelling changes of the hydrogel were observed in pH variations of a wide range (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). Ionic repulsion between charged groups incorporated in the gel matrix by an external pH modulation could be assumed as the main driving force responsible for such abrupt swelling changes.…”

Section: Discussionmentioning

confidence: 99%

“…Natural-based SAPs have attracted much attention in medical and pharmaceutical fields because of their non-toxicity, biocompatibility and biodegradability. Free radical vinyl graft copolymerization onto natural polymers is a well-known method for synthesis of natural-based superabsorbent hydrogels [12][13][14][15]. The first industrial superabsorbent hydrogel, hydrolyzed starch-graft-polyacrylonitrile was synthesized using this method [16].…”

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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“…Potassium persulfate (KPS) has been used to graft poly(N-vinylpyrrolidone) [14] and poly(2-acrylamido-2-methylpropanesulfonic acid) [15] on the chitosan backbone. Acrylic acid (AA) was recently grafted onto chitosan using the KPS/ferrous ammonium sulfate initiator system [16]. Most recently, another redox initiator system, named thiocarbonation-KBrO 3 , was used for grafting hydroxyethyl methacrylate onto chitosan [17].…”

Section: Introductionmentioning

confidence: 99%

Modified chitosan, 7 Graft copolymerization of methacrylonitrile onto chitosan using ammonium persulfate initiator

2004

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Graft copolymerization of methacrylonitrile (MAN) onto chitosan using ammonium persulfate (APS) as an initiator was studied. The reactions were carried out under argon atmosphere in a homogenous aqueous phase containing a small portion of acetic acid (AcOH). Evidence of graft copolymerization was obtained by FTIR spectroscopy, e.g., the appearance of nitrile in the spectrum of chitosan-graftpolymethacrylonitrile. The synthetic conditions were systematically optimized through studying the influential factors including temperature, as well as concentrations of initiator, MAN, AcOH, sodium dodecyl sulfate surfactant (SDS) and chitosan. The effects of individual factors were investigated by calculating and monitoring the variation of the grafting parameters, i.e., grafting ratio, grafting efficiency, add-on value, homopolymer content, and total conversion. The optimum condition was achieved at APS 0.0108 mol/L, MAN 0.201 mol/L, 80°C, SDS 0.0016 mol/L, chitosan 0.5 g, AcOH 0.0086 mol/L. The overall activation energy for the graft copolymerization was determined to be 7.3 kJ/mol.

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Hydrogels based on modified chitosan, 1. Synthesis and swelling behavior of poly(acrylic acid) grafted chitosan

Cited by 124 publications

References 30 publications

Synthesis, Characterization and Drug Release Behavior of pH‐Responsive O‐carboxymethyl Chitosan‐graft‐poly(N‐vinylpyrrolidone) Hydrogel Beads

Synthesis, Characterization and Drug Release Behavior of pH‐Responsive O‐carboxymethyl Chitosan‐graft‐poly(N‐vinylpyrrolidone) Hydrogel Beads

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

Modified chitosan, 7 Graft copolymerization of methacrylonitrile onto chitosan using ammonium persulfate initiator

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