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1
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STRUCTURAL AND SWELLING PROPERTIES OF HYDROGEL MEMBRANES BASED ON CHITOSAN CROSSLINKED WITH GLUTARALDEHYDE AND SODIUM TRIPOLYPHOSPHATE

100%
Gierszewska-Drużyńska M., Ostrowska-Czubenko J.
Progress on Chemistry and Application of Chitin and its Derivatives
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2015
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vol. 20
43-53
EN
Chemically and physically crosslinked chitosan hydrogel membranes were obtained by treatment of chitosan (Ch) with glutaraldehyde (GA) and with GA and subsequently with sodium tripolyphosphate (TPP). The formation of covalent and ionic crosslinks between Ch, GA and ionic TPP was confirmed by FTIR spectroscopy. The studies of dynamic swelling behaviour of synthesized membranes in buffer solutions of different pH (1.0, 7.4, 9.0) indicated that the swelling process obeyed a second-order kinetics. Values of an apparent swelling rate constant for Ch/GA and Ch/GA/TPP membranes were of the same order for acidic and neutral swelling media but they increased for alkaline solutions.
2
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APPLICATION OF CHITOSAN IONICALLY CROSSLINKED WITH SODIUM EDETATE FOR REACTIVE DYES REMOVAL FROM AQUEOUS SOLUTIONS

100%
Jóźwiak T., Filipkowska U., Szymczyk P., Kuczajowska-Zadrożna M., Mielcarek A.
Progress on Chemistry and Application of Chitin and its Derivatives
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2015
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vol. 20
82-96
EN
In this study, we investigated the effect of chitosan crosslinking with sodium edetate (SE) on its sorption capacity of Reactive Black 5 and Reactive Yellow 84 dyes. The first stage of the study allowed establishing conditions of chitosan crosslinking. The process of ionic crosslinking was effective only at pH 4 and at the optimal dose of sodium edetate ranging from 0.046 to 0.462 g/g CHs. Process temperature in the range of 20-60oC had no significant effect on the stability of crosslinked chitosan. Contrary to the non-crosslinked chitosan (CHs), chitosan crosslinked with sodium edetate (CHs-SE) was capable of dyes sorption at pH 3. Sorption of reactive onto both CHs and CHs-SE was the most effective at pH 4. Chitosan crosslinking with SE had a positive effect on the effectiveness of RB5 and RY84 sorption. This effect was especially tangible within the first ten or so hours of sorption. After 24 h of the process, the sorption capacity of CHs-SE against RB5 and RY84 reached 1296.69 mg/g and 1883.62 mg/g, respectively. In the case of CHs, sorption capacity achieved after the same time was lower and accounted for 1025.55 mg RB5/g and 1539.67 mg RY84/g.
3
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EQUILIBRIUM SWELLING STUDY OF CROSSLINKED CHITOSAN MEMBRANES IN WATER, BUFFER AND SALT SOLUTIONS

100%
Gierszewska M., Ostrowska-Czubenko J.
Progress on Chemistry and Application of Chitin and its Derivatives
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2016
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vol. 21
55-62
EN
Physically crosslinked membranes were prepared by treating chitosan (Ch) with pentasodium tripolyphosphate (TPP) at different reaction conditions. The equilibrium swelling ratio, Seq, of Ch/TPP membranes in water, buffer and salt solutions at 37 C were determined. The experimental data indicated, that Seq depended on pH of buffer solution and type and concentration of salt solution. Swelling capacity in water depended on the content of TPP ions in the membrane and crosslinking density
4
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MODIFICATION OF RELEASE RATE OF SALICYLIC ACID FROM CHITOSAN MEMBRANE

88%
Mucha M., Michalak I.
Progress on Chemistry and Application of Chitin and its Derivatives
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2012
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vol. 17
21 - 28
EN
Due to continued interest in biodegradable polymers, chitosan is one of the most commonly used polymers in the field of control release of active substances. Currently as carriers of drugs, among tablets, or micro spheres transdermal systems, called films, are used. The presented results apply to study a drug release in buffer of pH = 7.2 from chitosan film. To study the kinetics of controlled release salicylic acid was used as a model substance. Obtained films were cross-linked in TPP solution and were also modified by applying outsider layer to slow down the release process. Received transdermal systems were tested with swelling kinetics and the release kinetics of salicylic acid. The obtained systems were tested in relation to different temperature of cross-linking solution of chitosan, different thickness of studied matrices, the influence of outside layer and varying initial amount of salicylic acid.
5
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PERVAPORATIVE INVESTIGATION OF ETHYL ALCOHOL DEHYDRATION

88%
Gnus M., Dudek G., Turczyn R., Tórz A., Łącka D., Konieczny K., Łapkowski M.
Progress on Chemistry and Application of Chitin and its Derivatives
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2015
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vol. 20
54-63
EN
Pervaporative separation properties of crosslinked chitosan and alginate membrane on ethanol-water mixture at room temperature was studied. The influence of crosslinking agents on the separation properties were discussed. Selected crosslinking agents were affected differently on used polymer matrices. The better separation properties were obtained for membranes crosslinked by phosphoric (V) acid. The highest pervaporation separation index (309.6 kg/m2·h) and separation factor (52.6) were obtained for phosphoric (V) acid crosslinked alginate membranes, however, the greatest total flux (12.4 kg/m2·h) obtained for phosphoric acid crosslinked chitosan membranes
6
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INFLUENCE OF CROSSLINKING PROCESS CONDITIONS ON MOLECULAR AND SUPERMOLECULAR STRUCTURE OF CHITOSAN HYDROGEL MEMBRANE

88%
Gierszewska-Drużyńska M., Ostrowska-Czubenko J.
Progress on Chemistry and Application of Chitin and its Derivatives
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2011
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vol. 16
15 - 22
EN
Unmodified (Ch) and ionically crosslinked with sodium tripolyphosphate (Ch/TPP) chitosan membranes were prepared. Various crosslinking conditions (pH, crosslinking time) were applied. Differences in membrane molecular structure was examined using FTIR spectroscopy. Scanning electron microscopy (SEM) coupled with Energy Dispersive X-Ray (EDX) Spectrometer as well as atomic force microscopy (AFM) were used for estimation of an effect of crosslinking conditions on supermolecular structure of chitosan membrane. Strong effect of pH of crosslinking TPP solution on crosslinking agent distribution inside the membranes and roughness of membrane surface was found. Differences in membrane morphology prior and after crosslinking results from differences in crosslinking density.
7
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THE EFFECT OF IONIC CROSSLINKING ON THERMAL PROPERTIES OF HYDROGEL CHITOSAN MEMBRANES

75%
Gierszewska-Drużyńska M., Ostrowska-Czubenko J.
Progress on Chemistry and Application of Chitin and its Derivatives
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2010
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vol. 15
25 - 32
EN
Ionically crosslinked one‑component chitosan (Ch), two‑component chitosan/sodium alginate (Ch/NaAlg) and chitosan/pentasodium tripolyphosphate (Ch/TPP) membranes as well as three‑component chitosan/sodium alginate/pentasodium tripolyphosphate (Ch/NaAlg/TPP) membranes were prepared. Formation of ionic interactions between Ch and NaAlg and/or TPP was confirmed by FTIR analysis. An effect of a crosslinking process on thermal properties of hydrogel membranes was examined using TG/DTG/DTA and DSC methods. Changes in the number of thermal degradation steps of the studied hydrogel membranes were observed. Considering the temperature at which thermal degradation starts as a criterion of the thermal stability, it was concluded that the thermal stability increases according to the series: Ch/NaAlg ≈ Ch/NaAlg/TPP ≈ Ch/TPP
8
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STATE OF WATER IN NONCROSSLINKED AND CROSSLINKED HYDROGEL CHITOSAN MEMBRANES – DSC STUDIES

75%
Ostrowska-Czubenko J., Pieróg M., Gierszewska-Drużyńska M.
Progress on Chemistry and Application of Chitin and its Derivatives
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2011
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vol. 16
147 - 156
EN
Modified chitosan hydrogel membranes were prepared using glutaraldehyde (GA) and sodium citrate (NaCIT) as crosslinking agents. Molecular and supermolecular structure analyses of unmodified and modified chitosan membranes have been conducted by FTIR and X-ray spectroscopy. FTIR results showed covalent and ionic crosslinks formation between chitosan (Ch) and GA or simultaneously Ch, GA and NaCIT. The state of water in noncrosslinked and crosslinked chitosan membranes were analysed by differential scanning spectroscopy (DSC). Three types of water in hydrogel membranes were found: non-freezing bound water, freezing bound water and freezing free water, while there were variations in the amount of non-freezing bound water in these polymers. The effect of ionic crosslinking on water state, mainly on the nonfreezing water content, was discussed.
9
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On the inverse miniemulsion copolymerization and terpolymerization of acrylamide, N, N′-methylenebis(acrylamide) and methacrylic acid

75%
Capek I.
Open Chemistry
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2003
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vol. 1
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issue 3
291-304
EN
The kinetics of free-radical copolymerization and terpolymerization of acrylamide (AAm), N, N′-methylenebis(acrylamide) (MBA) and methacrylic acid (MA) in the inverse water/monomer/cyclohexane/Tween 85 miniemulsion was investigated. Polymerizable sterically-stable miniemulsions were formulated in cyclohexane as a continuous medium. Polymerizations are very fast and reach the final conversion within several minutes. The dependence of the polymerization rate vs. conversion is described by a curve with two nonstationary rate intervals. The maximum rate of polymerization slightly increases with increasing concentration of crosslinking monomer (MBA) and strongly decreases by the addition of MA. The rate of polymerization is inversely proportional to the 0.9th and 1.8th power of the particle concentration without and with MA, respectively. The number of polymer particles is inversely proportional to the 0.18th and 0.13th power of MBA concentration. The kinetic and colloidal parameters of the miniemulsion polymerization are discussed in terms of microemulsion polymerization model.
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