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Wyszukujesz frazę "crosslinking" wg kryterium: Temat


Tytuł:
Structural and swelling properties of hydrogel membranes based on chitosan crosslinked with glutaraldehyde and sodium tripolyphosphate
Autorzy:
Gierszewska-Drużyńska, Magdalena
Ostrowska-Czubenko, Jadwiga
Powiązania:
https://bibliotekanauki.pl/articles/1035178.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
chitosan
crosslinking
membranes
swelling kinetics
Opis:
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.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2015, 20; 43-53
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrogels based on ionically and covalently crosslinked alginates
Autorzy:
Walczak, J.
Marchewka, J.
Laska, J.
Powiązania:
https://bibliotekanauki.pl/articles/284594.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
hydrogels
alginate beads
crosslinking
cellulose
Opis:
In the presented research sodium alginate modified by ionic and covalent crosslinking in the form of hydrogel beads was examined. In the first step, sodium alginate was ionically crosslinked by treatment with calcium chloride. Different forms of crosslinked alginate were obtained depending on the calcium chloride concentration. The forms varied from shapeless gel to dense agglomerated spheres. The optimal structure were spherical beads separated from each other. Ionically crosslinked alginates were then subjected to covalent crosslinking with epichlorohydrin. For additional reinforcement the crosslinked beads of alginate were modified with cellulose nanofibers. The products were compared in terms of water absorption in the dry samples, their morphology was observed by scanning electron microscopy. Calcium ions distribution in the composites was evaluated by energy dispersive spectroscopy analysis. In vitro biodegradation of the crosslinked alginates was also investigated.
Źródło:
Engineering of Biomaterials; 2014, 17, no. 128-129; 109-110
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Equilibrium swelling study of crosslinked chitosan membranes in water, buffer and salt solutions
Autorzy:
Gierszewska, Magdalena
Ostrowska-Czubenko, Jadwiga
Powiązania:
https://bibliotekanauki.pl/articles/1034640.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
chitosan
crosslinking
equilibrium swelling
membranes
Opis:
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
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2016, 21; 55-62
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pervaporative investigation of ethyl alcohol dehydration
Autorzy:
Gnus, Małgorzata
Dudek, Gabriela
Turczyn, Roman
Tórz, Artur
Łącka, Dorota
Konieczny, Krystyna
Łapkowski, Mieczysław
Powiązania:
https://bibliotekanauki.pl/articles/1035004.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
alginate
chitosan
crosslinking
dehydration
pervaporation
Opis:
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
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2015, 20; 54-63
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coated NPK Fertilizer Based on Citric Acid-Crosslinked Chitosan/Alginate Encapsulant
Autorzy:
Mesias, Vince St. D.
Agu, Anne Bernadette S.
Benablo, Precious Japheth L.
Chen, Chun-Hu
Penaloza Jr., David P.
Powiązania:
https://bibliotekanauki.pl/articles/124714.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
controlled release
crosslinking
encapsulation
NPK fertilizer
Opis:
A coated nitrogen-phosphorus-potassium (NPK) fertilizer was prepared via crosslinking chitosan and alginate using citric acid. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), particle size analysis, and zeta potential measurement showed the successful crosslinking, appropriate size, and colloidal stability of the coated NPK fertilizer. The encapsulation capability of the crosslinked chitosan/alginate (Chi/Alg) was studied using fluorescence spectroscopy and NPK analysis. The release behavior studies under various pH conditions showed that Chi/Alg NPK conformed to the standards of controlled release fertilizer with a maximum release rate of 40% for 30 days. The investigation of the release mechanism using Korsemeyer-Peppas mathematical model showed that the release of nutrients is governed by both coating material relaxation and diffusion process.
Źródło:
Journal of Ecological Engineering; 2019, 20, 11; 1-12
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vapour permeation study of water and ethanol through crosslinked chitosan and alginate membranes
Autorzy:
Turczyn, Roman
Gnus, Małgorzata
Dudek, Gabriela
Tórz, Artur
Łącka, Dorota
Strzelewicz, Anna
Łapkowski, Mieczysław
Powiązania:
https://bibliotekanauki.pl/articles/1034919.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
alginate
chitosan
crosslinking agents
vapour permeation
Opis:
A vapour permeation of water and ethanol through homogenous chitosan and alginate membranes was investigated. The influence of the polymer matrix and crosslinking agents, and measurement protocol on the transport properties were discussed. The conducted experiments showed the greater separation factor, better stability and resistant to solvents for chemically crosslinked membranes. On the other hand, stronger association of the matrix, than the physical, caused decrease of vapour fluxes.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2015, 20; 281-288
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of crosslinking process conditions on molecular and supermolecular structure of chitosan hydrogel membrane
Autorzy:
Gierszewska-Drużyńska, Magdalena
Ostrowska-Czubenko, Jadwiga
Powiązania:
https://bibliotekanauki.pl/articles/1035415.pdf
Data publikacji:
2011
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
chitosan
crosslinking
membrane
morphology
supermolecular stucture
Opis:
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.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2011, 16; 15-22
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis of chitosan and carboxymethyl chitosan hydrogels by electron beam irradiation
Autorzy:
Czechowska-Biskup, Renata
Wach, Radosław
Stojek, Piotr
Kamińska, Martyna
Rosiak, Janusz M.
Ulański, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/1034681.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
PEGDA
carboxymethyl chitosan
chitosan
hydrogel
radiation crosslinking
Opis:
Solutions of chitosan (CS) and carboxymethyl chitosan (CMCS) were subjected to irradiation by electron beam in presence of a crosslinking agent (poly(ethylene glycol) diacrylate - PEGDA) in order to produce carboxymethyl chitosan- and chitosan-based hydrogels. PEGDA macromonomer itself undergoes simultaneous polymerization and crosslinking either in neutral water or in acidic medium. Acidic solutions of chitosan of 0.5, 1 and 2% can be effectively crosslinked with PEGDA to form a gel. Although CMCS undergoes radiation-initiated crosslinking only at high concentration in water (over 10%), the presence of PEGDA in solution facilitated hydrogel formation even at lower concentration of CMCS. Formation of CS and CMCS hydrogels required irradiation doses lower than those needed for sterilization, i.e. 25 kGy, in some cases even as low as 200 Gy. Sol-gel analysis revealed relatively high gel fraction of obtained hydrogels, up to 80%, and good swelling ability. Both parameters can be easily controlled by composition of the initial solution and irradiation dose. Possible mechanisms of crosslinking reactions were proposed, involving addition of the polysaccharide macroradicals to a terminal double bond of PEGDA.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2016, 21; 27-45
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modification of release rate of salicylic acid from chitosan membrane
Autorzy:
Mucha, Maria
Michalak, Iwona
Powiązania:
https://bibliotekanauki.pl/articles/1035374.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
chitosan
crosslinking
release
salicylic acid
transdermal systems
Opis:
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.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2012, 17; 21-28
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis impact fracturing fluid acidity on structural strength of crosslinked gel complex
Autorzy:
Krzeczek, P.
Karasek, P.
Wojnarowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/299086.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
hydraulic fracturing
fracturing fluid
linear gel
crosslinking
Opis:
Nowadays hydraulic fracturing is the most commonly used technique to stimulate the productivity of a well. The selection of a proper fracturing fluid is all about choices which strongly influence on effectiveness of the treatment. It should be carefully prepared, supported by lab analysis in order to match fluid to reservoir condition. This article concerns impact of fracturing fluid additives on fluid properties. In the paper crosslinking process has been shown and its importance on conventional reservoir rocks fracturing treatment. Provided lab examination shows fluid pH impact during creation crosslinked gel complex including influence to crosslinking time in the surface condition. The lower linear gel pH caused lower crosslinking time of fracturing fluid.
Źródło:
AGH Drilling, Oil, Gas; 2017, 34, 2; 385-395
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł

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