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1

Equilibrium swelling behavior of crosslinked chitosan hydrogels

Ostrowska-Czubenko J., Pieróg M., Gierszewska-Drużyńska M.

Polish Journal of Applied Chemistry

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2011

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Vol. 55, nr 2

49-56

EN

Chemically and physically crosslinked chitosan hydrogels were obtained by treating chitosan (Ch) with glutaraldehyde (GA) and sodium tripolyphosphate or GA and sodium citrate, GA and sulfuric acid and GA and sulfosuccinic acid, respectively. The formation of covalent and ionic crosslinks between Ch, GA and low molecular ionic compounds was confirmed by FTIR spectroscopy. There was examined the equilibrium degree of swelling of membranes formed from uncrosslinked and crosslinked chitosan hydrogels in buffer solutions of different pH. It was observed that the swelling of all studied membranes was highly dependent on pH.

2

Efect of ionic crosslinking on chitosan membrane swelling in extracellular hanks' buffer

Gierszewska-Drużyńska M., Ostrowska-Czubenko J.

Polish Journal of Applied Chemistry

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2011

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Vol. 55, nr 1

1-9

EN

Two- and three-component chitosan membranes (Ch) crosslinked with sodium tripolyphosphate (TPP) and/or sodium alginate (NaAlg) were prepared. Formation of ionic crosslinks between Ch and high-molecular compound - NaAlg and/or low-molecular - TPP was confirmed by FTIR spectroscopy. The effcct of crosslinking agents on membrane swelling in extracellular Hanks' buffer was estimated. The obtained results allow to state, that ionic crosslinking of chitosan results in increase of membrane stability in extracellular media. However, only TPP crosslinkcd chitosan membranes are not soluble in Hanks' buffer.

3

Application of pervaporation and osmotic membrane distillation to the regeneration of spent solutions from the osmotic food dehydration

Kujawski W., Gierszewska-Drużyńska M., Warczok J., Güell C.

Polish Journal of Chemical Technology

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2009

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Vol. 11, nr 2

41-45

EN

Results of pervaporation (PV) of sucrose and calcium chloride spent solutions were presented. Additionally, osmotic membrane distillation (OMD) of sucrose solutions was investigated. It was found that the regeneration of spent sucrose solution for the reuse is possible by using PV or OMD processes. However, OMD process produces another spent stream i.e. CaCl2. Pervaporation membranes showed fluxes in the range of 0.5 - 0.9 kg m^-2 h^-1 in contact with 40° Brix sucrose solution, whereas OMD water permeate fluxes were in the range of 4 - 5 kg m^-2 h^-1 for the same feed concentration. Two different hybrid processes were suggested: i) pretreatment followed by OMD reconcentration of spent sucrose solution and independently PV for CaCl2 regeneration; ii) membrane pretreatment (MP) followed by PV of sucrose solution. Based on the experimental results, the membrane areas for both systems were calculated and compared. MP-PV system seems to be a better solution for the spent mixtures management.

4

State of water in chitosan /tripolyphosphate polyelektrolyte complex membranes for pervaportation

Gierszewska-Drużyńska M., Ostrowska-Czubenko J.

Polish Journal of Applied Chemistry

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2009

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Vol. 53, nr 1

15-21

EN

Polyelectrolyte complexes (PECs) are known as new interesting membrane materials applicable in industry, medicine and pharmacy. In this work PEC membranes from chitosan (Ch) and pentasodium tripolyphosphate (TPP) designed for pervaporation w'ere prepared by dipping Ch membranes in TPP solution. The PEC formation between Ch and TPP was confirmed by FTIR spectroscopy. Various amounts of w'ater were added into the dry ChATPP hydrogels to cause them to swell, and the amounts of water in various states were determined by the DSC ice-melting technique. Three types of water in hydrogel membranes w'ere identified: non-freezing bound water, freezing bound water, and freezing free w'ater. States of water in Ch/TPP and Ch membranes were compared and the effect of ionic crosslinking on the non-freezing water content was discussed.

5

Synteza i właściwości membran hydrożelowych na podstawie chitozanu oraz alginianu sodu

Gierszewska-Drużyńska M., Ostrowska-Czubenko J.

Polimery

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2007

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T. 52, nr 7-8

517-523

PL

Badaniom poddano membrany hydrożelowe formowane z kompleksów polielektrolitowych (PEC) otrzymanych w wyniku reakcji chitozanu z alginianem sodu. Tworzenie kompleksów potwierdzono techniką FTIR. Tak zwany stan wody (state of water) w membranach o różnej całkowitej zawartości wody (Wc) scharakteryzowano z zastosowaniem metody skaningowej kalorymetrii różnicowej (DSC). Wyróżniono trzy różne typy wody w membranach hydrożelowych: wodę wolną, wodę związaną z polimerem ulegającą wymrożeniu i wodę związaną z polimerem nieulegającą wymrożeniu. Określono zawartość wody ulegającej wymrożeniu (Wf) i nieulegającej wymrożeniu (Wnf) w membranach o różnej wartości Wc oraz ciepło topnienia wody ulegającej wymrożeniu (?Hm). Na podstawie przebiegu krzywych DSC wyciągnięto wnioski dotyczące mikroheterogenicznej struktury membran formowanych z badanych PEC. Ustalono, że ciężar cząsteczkowy chitozanu wywiera niewielki tylko wpływ na stan wody w badanych membranach.

EN

Hydrogel membranes formed from polyelectrolyte complexes (PEC) obtained in the reactions of chitosan with sodium alginate (Scheme A) were investigated. The formation of complexes has been confirmed by FTIR method (Fig. 1). So called state of water in the membranes of different total water content (Wc) was characterized by differential scanning calorimetry (DSC) (Fig. 2 and 3). Three various types of water in the membranes were distinguished: free water, freezing water and non-freezing water. The contents of freezing (Wf) and non-freezing water (Wnf) in the membranes of various Wc (Fig. 5 and 6) as well as heat of fusion of freezing bound water (?Hm) (Fig. 4) were determined. The courses of DSC curves let come to the conclusions concerning microheterogenic structures of membranes formed from PEC investigated. It was found that molecular weight of chitosan very slightly influenced the state of water in the membranes tested.