Novel synthesis of thermosensitive porous hydrogels

Gotoh, Takehiko; Nakatani, Yuko; Sakohara, Shuji

doi:10.1002/(sici)1097-4628(19980801)69:5<895::aid-app8>3.0.co;2-h

Cited by 135 publications

(95 citation statements)

References 9 publications

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“…4,5 Therefore, creation of porosity in hydrogels has been considered as an important process in many ways. [6][7][8] According to our prior works, 9,10 neutralization of the grafted polymer after gel formation or gas releasing during hydrolyzation create a hydrogel with porous structure.…”

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Salt- and pH-Resisting Collagen-based Highly Porous Hydrogel

Pourjavadi

Kurdtabar

Ghasemzadeh

2007

Polym J

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A novel approach was developed to prepare a highly porous hydrogel with superior salt-and pH-resisting properties. According to this method, synthetic comonomers, i.e. acrylic acid (AA) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS), were polymerized and crosslinked in the presence of hydrolyzed collagen as a natural backbone. The characterizations of hydrogels were investigated by swelling experiment, Fourier transform infrared (FT-IR) spectroscopy, acid-base titration and thermogravimetric analysis (TGA). Morphology of the samples was examined by scanning electron microscopy (SEM). Experimental results indicate that the hydrogel has an absorbency of 360 and 73-82 g/g for distilled water and saline solutions, respectively. Water absorbency slightly changes from pH 3 to 8 and interestingly is more than of that in distilled water ($ 500 g/g). The hydrogel thus prepared was showing a better salt-and pH-resistance compared to collagen-g-PAA hydrogel due to the introduction of the AMPS segment and therefore is a suitable candidate for horticulture and tissue engineering applications.KEY WORDS: Hydrolyzed Collagen / Hydrogel / Porous / Salt-resisting / pH-Resisting / Hydrogels are an important class of materials have been attracting in many industrial applications because of their response to changing environment conditions such as temperature, 1 pH 2 and solvent composition. 3 Although their attraction in medical and mechanical engineering fields, the technological success of these applications is today limited by their low efficiency and slow rate of response to external stimuli. These are related to the degree of porosity which plays the multiple role of enhancing the total water sorption capability and the rate of response by reducing the transport resistance.4,5 Therefore, creation of porosity in hydrogels has been considered as an important process in many ways.6-8 According to our prior works, 9,10 neutralization of the grafted polymer after gel formation or gas releasing during hydrolyzation create a hydrogel with porous structure.It is desired to develop hydrogels having enhanced absorbency in saline solutions, in various values of pH and good strength of the swollen gel (high absorbency under load), since the requirements of such applications as long-term water holding in horticulture and hygienic products, and the like. So that there have already several studies focusing on improving some hydrogel properties, and further more some modification method seemed effective.11-14 On the basis of our former researches, 9,15 we have been interested in preparing a hydrogel which possess relatively high water absorbency under certain load and at atmosphere pressure in salt solution.Natural-based hydrogels have attracted in medical and pharmaceutical interests since their non-toxicity, biocompatibility and biodegradability. This paper describes the preparation and characterization of a partially neutralized collagen-gpoly(AA-co-AMPS) porous hydrogel, as a new natural-based polymer, which shows salt-and pH-resist...

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confidence: 99%

Salt- and pH-Resisting Collagen-based Highly Porous Hydrogel

Pourjavadi

Kurdtabar

Ghasemzadeh

2007

Polym J

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“…One approach to improve swelling-deswelling rates was to synthesize porous PNIPA gels. Porous PNIPA gels have been prepared by several methods such as the incorporation of surfactants 5 or silica particles 6 during hydrogel preparation and their subsequent extraction, hydrogel preparation above its LCST, [7][8][9][10] and preparation using freezedrying. 11 Recently, Gotoh et al…”

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Synthesis of Porous Poly(N-isopropylacrylamide) Gel Beads by Sedimentation Polymerization

Iizawa

Ninomiya

Gotoh

et al. 2004

Polym J

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“…29,30 Therefore, creation of porosity in hydrogels has been considered as an important process in many ways. The phase-separation technique, 31 the water-soluble porogens 32 and the foaming technique 33,34 are three different methods for preparing porous hydrogel structures. In this paper, as mentioned above, however, the pores were simply produced from NH 3 gas resulting from alkaline hydrolysis.…”

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confidence: 99%

Synthesis and Properties of Partially Hydrolyzed Acrylonitrile-co-Acrylamide Superabsorbent Hydrogel

Pourjavadi¹,

Hosseinzadeh²

2010

Bulletin of the Korean Chemical Society

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In this work, a novel method to synthesis of an acrylic superabsorbent hydrogel was reported. In the two stage hydrogel synthesis, first copolymerization reaction of acrylonitrile (AN) and acrylamide (AM) monomers using ammonium persulfate (APS) as a free radical initiator was performed. In the second stage, the resulted copolymer was hydrolyzed to produce carboxamide and carboxylate groups followed by in situ crosslinking of the polyacrylonitrile chains. The results from FTIR spectroscopy and the dark red-yellow color change show that the copolymerization, alkaline hydrolysis and crosslinking reactions have been do take place. Scanning electron microscopy (SEM) verifies that the synthesized hydrogels have a porous structure. The results of Brunauer-Emmett-Teller (BET) analysis showed that the average pore diameter of the synthesized hydrogel was 13.9 nm. The synthetic parameters affecting on swelling capacity of the hydrogel, such as AM/AN weight ratio and hydrolysis time and temperature, were systematically optimized to achieve maximum swelling capacity (330 g/g). The swollen gel strength of the synthesized hydrogels was evaluated via viscoelastic measurements. The results indicated that superabsorbent polymers with high water absorbency were accompanied by low gel strength. The swelling of superabsorbent hydrogels was also measured in various solutions with pH values ranging from 1 to 13. Also, the pH reversibility and on-off switching behavior makes the hydrogel as a good candidate for controlled delivery of bioactive agents. Finally, the swelling of synthesized hydrogels with various particle sizes obey second order kinetics.

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Novel synthesis of thermosensitive porous hydrogels

Cited by 135 publications

References 9 publications

Salt- and pH-Resisting Collagen-based Highly Porous Hydrogel

Salt- and pH-Resisting Collagen-based Highly Porous Hydrogel

Synthesis of Porous Poly(N-isopropylacrylamide) Gel Beads by Sedimentation Polymerization

Synthesis and Properties of Partially Hydrolyzed Acrylonitrile-co-Acrylamide Superabsorbent Hydrogel

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