Temat: crosslinking - Katalog OPAC zbiorów

Skocz do pozycji: 1.

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

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Skocz do pozycji: 2.

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

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Skocz do pozycji: 3.

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

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Skocz do pozycji: 4.

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

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Skocz do pozycji: 5.

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

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Skocz do pozycji: 6.

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

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Skocz do pozycji: 7.

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

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Skocz do pozycji: 8.

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

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Skocz do pozycji: 9.

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

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Skocz do pozycji: 10.

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

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Skocz do pozycji: 11.

Tytuł:: Application of chitosan ionically crosslinked with sodium edetate for reactive dyes removal from aqueous solutions
Autorzy:: Jóźwiak, Tomasz
Filipkowska, Urszula
Szymczyk, Paula
Kuczajowska-Zadrożna, Małgorzata
Mielcarek, Artur
Powiązania:: https://bibliotekanauki.pl/articles/1034883.pdf
Data publikacji:: 2015
Wydawca:: Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:: chitosan beads
crosslinking
dyes sorption
sodium edetate
Opis:: 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.
Źródło:: Progress on Chemistry and Application of Chitin and its Derivatives; 2015, 20; 82-96
1896-5644
Pojawia się w:: Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Synthesis and potential cytotoxicity evaluation of carboxymethyl chitosan hydrogels
Autorzy:: Kłosiński, Karol K.
Girek, Małgorzata K.
Wach, Radosław A.
Czechowska-Biskup, Renata
Arkuszewski, Piotr T.
Szymański, Paweł B
Pasieka, Zbigniew
Powiązania:: https://bibliotekanauki.pl/articles/1034588.pdf
Data publikacji:: 2017
Wydawca:: Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:: PEGDA
XTT
carboxymethyl chitosan
cytotoxicity
hydrogel
radiation crosslinking
Opis:: The aim of the research was to employ radiation to produce flexible carboxymethyl chitosan (CMCS) based hydrogels of uniform structure to characterise their swelling properties and cytocompatibility for potential applications as hydrogel wound dressings. CMCS in aqueous solution was irradiated with an electron beam in the presence of a poly(ethylene glycol) diacrylate (PEGDA) macromonomer as a crosslinker, at 12 different compositions, i.e. 3–20% CMCS, 3 and 5% PEGDA. The obtained hydrogels were subjected to sol–gel analysis. The amount of insoluble fraction (up to 100%) rose with an increase in the PEGDA/polysaccharide ratio. Moreover, the equilibrium degree of swelling, ca. 15 to 200 g of water per g of gel, which was higher for lower content of crosslinker, decreased with the delivered dose, which was associated with an increase in crosslinking density. The in vitro XTT cell viability assay (murine fibroblasts, L929 cell line) showed no significant cytotoxicity of CMCS gels.
Źródło:: Progress on Chemistry and Application of Chitin and its Derivatives; 2017, 22; 82-96
1896-5644
Pojawia się w:: Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: Effect of cross-linking with glutaraldehyde on adsorption capacity of chitosan beads
Autorzy:: Jóźwiak, Tomasz
Filipkowska, Urszula
Rodziewicz, Joanna
Nowosad, Ewa
Powiązania:: https://bibliotekanauki.pl/articles/1035335.pdf
Data publikacji:: 2013
Wydawca:: Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:: adsorption
chitosan beads
crosslinking chitosan beads
dyes
glutaraldehyde
Opis:: The study was undertaken to analyze the effect of chitosan cross-linking with glutaraldehyde on the adsorption capacity of chitosan beads during adsorption of Reactive Black (RB5) and Basic Green (BG4) dyes. Analyses were conducted at three pH values: pH 3.0; 5.0 and 9.0. Results obtained were evaluated with the use of four models of adsorption isotherms Freundlich, Langmuir, Double Langmuir and Redlic-Petreson. The cross-linking of beads with glutaraldehyde turned out to be beneficial for the anionic dye RB5. Compared to the non-cross-linked beads, a comparable adsorption capacity (over 500 mg/g d.m.) was obtained at pH 3.0 and pH 5.0. In the case of the cationic dye, chitosan cross-linking reduced the quantity of adsorbed dye, irrespective of the pH value of the adsorption process.
Źródło:: Progress on Chemistry and Application of Chitin and its Derivatives; 2013, 18, 18; 35-47
1896-5644
Pojawia się w:: Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: The effect of ionic crosslinking on thermal properties of hydrogel chitosan membranes
Autorzy:: Gierszewska-Drużyńska, Magdalena
Ostrowska-Czubenko, Jadwiga
Powiązania:: https://bibliotekanauki.pl/articles/1035522.pdf
Data publikacji:: 2010
Wydawca:: Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:: DSC
TG/DTG
chitosan
crosslinking
hydrogel
thermal stability
Opis:: 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
Źródło:: Progress on Chemistry and Application of Chitin and its Derivatives; 2010, 15; 25-32
1896-5644
Pojawia się w:: Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 15.

Tytuł:: Wpływ środowiska zasadowego na wydajność reakcji Hecka stosowanej do sieciowania kauczuku chloroprenowego
The influence of basic environment on the efficiency of Heck reaction applied for crosslinking chloroprene rubber
Autorzy:: Dziemidkiewicz, Anna
Maciejewska, Magdalena
Powiązania:: https://bibliotekanauki.pl/articles/272864.pdf
Data publikacji:: 2019
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Inżynierii Materiałów Polimerowych i Barwników
Tematy:: reakcja Hecka
trietanoloamina
sieciowanie
kauczuk chloroprenowy
układ sieciujący przyjazny dla środowiska
Heck reaction
triethanolamine
crosslinking
chloroprene rubber
environmentally friendly crosslinking system
Opis:: Celem przeprowadzonych badań było określenie wpływu trietanoloaminy (TEOA) na wydajność reakcji Hecka stosowanej do sieciowania kauczuku chloroprenowego (CR). Zaproponowany układ sieciujący jest nowym przykładem zastosowania, doskonale znanej w syntezie organicznej, reakcji Hecka [1]. Reakcja ta jest jedną z głównych metod tworzenia wiązań podwójnych węgiel–węgiel (C=C) w syntezie organicznej. Nie odnotowano jak dotąd żadnego wykorzystania reakcji Hecka w technologii elastomerów. Sporządzono mieszanki kauczukowe zawierające acetyloacetonian żelaza(II) (Fe(acac)2) jako nowy środek sieciujący z różną zawartością TEOA (1–5 cz. mas.). Dodatkowo mieszanki napełniono krzemionką (SiO2) pirogeniczną Aerosil 380 lub sadzą (CB) N550. Uzyskane wyniki wykazały, że zarówno ilość TEOA, jak i rodzaj napełniacza miały istotny wpływ na właściwości otrzymanych elastomerów. W przypadku kompozytów napełnionych CB aktywność Fe(acac)2 w procesie sieciowania wzrastała wraz z ilością TEOA. Potwierdziły to wysokie wartości przyrostu momentu obrotowego i stopnia usieciowania CR oraz krótsze czasy wulkanizacji. W przypadku mieszanek napełnionych SiO2 wpływ ilości TEOA na wydajność procesu sieciowania nie był tak jednoznaczny. Jednak biorąc pod uwagę przyrost momentu obrotowego, stopień usieciowania oraz optymalny czas wulkanizacji można stwierdzić, że użycie 3 cz. mas. TEOA skutkowało największą aktywnością Fe(acac)2.
The aim of the study was to determine the effect of triethanolamine (TEOA) on the efficiency of Heck’s reaction used for the crosslinking of chloroprene rubber (CR). The proposed crosslinking system is a new example of the application of the Heck reaction, well known in organic synthesis [1]. This reaction is one of the main methods of creating carbon‑carbon double bonds (C=C) in organic synthesis. So far, no use of Heck’s reaction in elastomer technology has been reported. Rubber blends containing iron(II) acetylacetonate (Fe(acac)2) as a new crosslinking agent with different TEOA content (1–5 phr) were prepared. Additionally, the blends were filled with pyrogenic silica (SiO2) Aerosil 380 or carbon black (CB) N 550. The obtained results showed that both the amount of TEOA and the type of filler had a significant effect on the properties of the elastomers obtained. In case of composites filled with CB, the activity of Fe(acac)2 in the crosslinking process increased with the amount of TEOA. This was confirmed by high values of torque increment and degree of crosslinking of CR and shorter vulcanization times. In case of rubber compounds filled with SiO2, the effect of TEOA on the efficiency of crosslinking process was not so unambiguous. However, considering the increase in torque, the degree of crosslinking and the optimum vulcanization time, it can be stated that the use of 3 phr. TEOA resulted in the highest Fe(acac)2 activity.
Źródło:: Elastomery; 2019, 23, 3; 163-174
1427-3519
Pojawia się w:: Elastomery
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 16.

Tytuł:: Manufacturing of solvent-free acrylic pressure-sensitive adhesives in form of self-adhesive layers
Autorzy:: Czech, Z.
Sowa, D.
Ragańska, P.
Powiązania:: https://bibliotekanauki.pl/articles/412416.pdf
Data publikacji:: 2013
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:: pressure-sensitive
acrylics
adhesive
polymerization
solvent-free
UV-crosslinking
Opis:: The present publication is related to a process for producing the non-solvent acrylic pressure-sensitive adhesive (PSA). New applications and technical specifications stimulate the continuous development of new methods of polymerization of solvent-free acrylate. New synthesis of solvent-free acrylics includes polymerization in the reactor with removal of the solvent and polymerization of the carrier. The polymerization process is connected with UV-crosslinking.
Źródło:: International Letters of Chemistry, Physics and Astronomy; 2013, 8, 2; 147-159
2299-3843
Pojawia się w:: International Letters of Chemistry, Physics and Astronomy
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 17.

Tytuł:: The effect of crosslinking conditions on the dynamic viscosity of organosilicon polymers
Autorzy:: Nowacka, Agnieszka
Klepka, Tomasz
Powiązania:: https://bibliotekanauki.pl/articles/109560.pdf
Data publikacji:: 2019
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: abrasive flow machining
organosilicon polymers
abrasive medium
crosslinking conditions
Opis:: This study presents research concerning the development of an organosilicon polymer medium (polymethylhydroborosiloxane), that allows for the optimal selection of viscosity in the medium, for use as an admixture abrasive paste for abrasive flow machining. Based on the results of actual dynamic viscosity medium measurements, the influence of changes in temperature (25 °C, 50 °C and 75 °C) and in the concentration of the crosslinking solution (anhydrite boric acid – 2 wt.%, 4 wt.% and 6 wt.%) were studied. A number of crosslinking medium experiments were carried out, in which the characteristics of storage modulus G' and loss modulus G" of the medium containing different concentrations of crosslinking solutions at different temperature were determined. Due to the results obtained, it was possible to select the parameters of the crosslinking solution optimally both in terms of the temperature (50 °C) as well as its concentration (4 wt.%).
Źródło:: Physicochemical Problems of Mineral Processing; 2019, 55, 6; 1557-1567
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 18.

Tytuł:: Effect of ionic crosslinking on density of hydrogel chitosan membranes
Autorzy:: Gierszewska-Drużyńska, Magdalena
Ostrowska-Czubenki, Jadwiga
Kwiatkowska, Anita
Powiązania:: https://bibliotekanauki.pl/articles/1035221.pdf
Data publikacji:: 2013
Wydawca:: Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:: chitosan membranes
density
ionic crosslinking
n-heptane
pycnometer method
Opis:: Ionically crosslinked chitosan membranes were prepared and their density was determined using modified pycnometer method. High molecular compound: sodium alginate (NaAlg) and low molecular compounds: pentasodium tripolyphosphate (TPP) and trisodium citrate (CIT) were used as ionic crosslinkers of chitosan. As a reference liquid n-heptane solution was chosen. It was found out that density of modified chitosan membranes is strongly affected by the type of ionic crosslinker and membrane preparation conditions
Źródło:: Progress on Chemistry and Application of Chitin and its Derivatives; 2013, 18, 18; 49-57
1896-5644
Pojawia się w:: Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 19.

Tytuł:: The formation of hydrogels based on chitosan and its water-soluble derivatives
Autorzy:: Il’ina, Alla V.
Shagdarova, Balzhima Ts.
Lunkov, Alexey P.
Varlamov, Valery P.
Powiązania:: https://bibliotekanauki.pl/articles/1034059.pdf
Data publikacji:: 2020
Wydawca:: Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:: chitosan
crosslinking agent
gelation
hydrogels
quaternized chitosan
succinyl chitosan
Opis:: This review considers articles on the formation of hydrogels based on chitosan as well as succinylated and quaternized chitosan derivatives. They are synthesized using low toxicity reagents, under ordinary conditions (low production costs). Chitosan derivatives are soluble in an extended range of pH values and characterized by mucoadhesiveness, bioavailability and biodegradability, which extends the potential of their medical applications. One of the most important properties of chitosan and its derivatives is the ability to form hydrogels. Depending on the nature of the bonds that occur during formation, hydrogels are divided into chemically or physically crosslinked, or a mixture of the two. Chemically crosslinked gels have covalent bonds, while physically crosslinked gels are formed by noncovalent interactions, for example, ionic. Mixed hydrogels have both types of crosslinking.
Źródło:: Progress on Chemistry and Application of Chitin and its Derivatives; 2020, 25; 5-15
1896-5644
Pojawia się w:: Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 20.

Tytuł:: Morphological, Mechanical and Physio-chemical Performance of ortho-Cresol Epoxy Novolac Based Vinyl Ester Resin
Autorzy:: Jaswal, S.
Gaur, B.
Powiązania:: https://bibliotekanauki.pl/articles/779370.pdf
Data publikacji:: 2015
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:: thermosetting resins
crosslinking reactions
thermal behavior
mechanical properties
chemical resistance
Opis:: Vinyl ester resin (VEOCN) was prepared from o-cresol epoxy resin (EOCN) and methacrylic acid in the presence of triphenyl phosphine as catalyst and hydroquinone as inhibitor with acid value of ~ 7 mg of KOH per gram of solid. O-cresol based novolac resin (OCN), OCN based epoxy resin (EOCN) and VEOCN were characterized by Fourier transform infra red spectroscopy (FT-IR), 1H-NMR and 13C-NMR. The thermal and mechanical behavior of the samples prepared at 30°C from VEOCN using styrene and methyl-methacrylate respectively as reactive diluents, in the presence of benzoyl peroxide (2 phr) as initiator was studied using Differential Scanning Calorimetry (DSC), Thermogravimetric analysis (TGA) and Universal Testing Machine (UTM). Chemical resistance of above VER samples was also evaluated as a function of % weight loss and with the help of Scanning Electron Microscopy (SEM), upon immersing the VEOCN samples in different solutions for 90 days.
Źródło:: Polish Journal of Chemical Technology; 2015, 17, 3; 1-7
1509-8117
1899-4741
Pojawia się w:: Polish Journal of Chemical Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 21.

Tytuł:: Hydrożele alginianowe sieciowane jonowo i kowalencyjnie
Hydrogels based on ionically and covalently crosslinked alginates
Autorzy:: Walczak, J.
Marchewka, J.
Laska, J.
Powiązania:: https://bibliotekanauki.pl/articles/284020.pdf
Data publikacji:: 2015
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:: hydrożele
mikrosfery alginianowe
sieciowanie
celuloza
hydrogels
alginate beads
crosslinking
cellulose
Opis:: W niniejszej pracy zaprezentowano metodę otrzymywania mikrosfer hydrożelowych o podwyższonej wytrzymałości mechanicznej. Alginian sodu w formie mikrosfer hydrożelowych poddano sieciowaniu jonowemu i kowalencyjnemu. Sieciowanie przeprowadzono dwuetapowo. W pierwszym etapie alginian sodu usieciowano jonowo poprzez wymianę jednowartościowych kationów sodu na dwuwartościowe kationy wapnia. W zależności od stężenia chlorku wapnia otrzymano różne formy hydrożelu, od bezkształtnego żelu do gęstych aglomeratów mikrosfer. By uzyskać wyższą wytrzymałość mechaniczną jonowo usieciowanego hydrożelu, dodatkowo poddawano go reakcji z epichlorohydryną. Reakcja ta pozwoliła wprowadzić pomiędzy łańcuchy alginianu mostki kowalencyjne. Otrzymano również usieciowane mikrosfery alginianowe zmodyfikowane włóknami celulozy, które stanowiły dodatkowe wzmocnienie mechaniczne. Zbadano wpływ stopnia usieciowania na absorpcję wody przez suche próbki. Morfologię otrzymanych mikrosfer obserwowano za pomocą skaningowej mikroskopii elektronowej. Rozkład jonów wapnia w próbkach oceniono przy użyciu spektroskopii z dyspersją energii. Zbadano także degradację mikrosfer in vitro w płynie PBS.
In this work a method of formation of hydrogel beads with increased mechanical durability is presented. Sodium alginate in the form of hydrogel beads was modified by ionic and covalent crosslinking. The crosslinking was achieved in two steps. In the first step, sodium alginate was ionically crosslinked by the ionic exchange of monovalent sodium cations with bivalent calcium cations. Different forms of the crosslinked alginate were obtained depending on the calcium chloride concentration. The forms varied from shapeless gel to hard agglomerated spheres. To increase mechanical durability of the ionically crosslinked alginate it was subjected to the reaction with epichlorohydrin. The reaction allowed to introduce covalent bridges between alginate chains. For additional reinforcement the crosslinked beads of alginate were modified with cellulose nanofibers. Dependence of water absorption in the dry samples on the crosslinking level was observed. Morphology of the beads was observed with the use of scanning electron microscopy. Calcium ions distribution in the samples was evaluated by energy dispersive spectroscopy analysis. In vitro degradation of the crosslinked alginates was also investigated.
Źródło:: Engineering of Biomaterials; 2015, 18, 132; 17-23
1429-7248
Pojawia się w:: Engineering of Biomaterials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 22.

Tytuł:: State of water in noncrosslinked and crosslinked hydrogel chitosan membranes – dsc studies
Autorzy:: Ostrowska-Czubenko, Jadwiga
Pieróg, Milena
Gierszewska-Drużyńska, Magdalena
Powiązania:: https://bibliotekanauki.pl/articles/1035477.pdf
Data publikacji:: 2011
Wydawca:: Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:: DSC
chitosan membranes
crosslinking
glutaraldehyde
states of water
trisodium citrate.
Opis:: 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.
Źródło:: Progress on Chemistry and Application of Chitin and its Derivatives; 2011, 16; 147-156
1896-5644
Pojawia się w:: Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 23.

Tytuł:: Radioisotopic investigation of crosslinking density in bovine pericardium used as a biomaterial
Autorzy:: Turek, A.
Cwalina, B.
Kobielarz, M.
Powiązania:: https://bibliotekanauki.pl/articles/147957.pdf
Data publikacji:: 2013
Wydawca:: Instytut Chemii i Techniki Jądrowej
Tematy:: bioprostheses
bovine pericardium (BP)
crosslinking
methylene blue (MB)
photooxidation
radioisotopic investigations
Opis:: Stabilized bovine pericardium (BP) belongs to tissues routinely applied in production of heart valves. Commercial products are manufactured from tissues crosslinked by glutaraldehyde (GA). Dye-mediated photooxidation was also proposed as an alternative method, which allows for the elimination of clinical failures of GA-treated tissues. The aim of the study was to investigate the density of BP stabilized by GA and the methylene blue-mediated photooxidation, as compared with a native tissue. Crosslinking density was evaluated based on their ability to accumulate radioactive cobalt ions (60Co2+) and the permeability to these ions. Radioactivity was examined using a γ-spectrophotometer (Packard). The results showed the changes in the crosslinking density between the native tissues and photooxidized or GA-crosslinked tissues. Significant decreases in radioactivity were detected only in the thinnest tissues after photooxidation and in filtrates penetrating the same samples. Photooxidized pericardium of a larger thickness did not reveal any significant changes. Weight-dependence for the permeability was observed in the case of filtrates penetrating the GA-treated tissues. However, 60Co2+-accumulation in these samples remained at the same level. Photooxidation may lead to obtaining biomaterials with advantageous properties, i.e. a decreased calcium-binding capacity. Photooxidation efficiencies were dependent both on compactness and thickness of tissues and on process duration. It should be emphasized that the tissues’ structure after photooxidation was characterized by lower density. This may point to the presence of crosslinks of a smaller compactness in comparison with GA treatment. It has been shown that the factor indeed influencing the result of crosslinking is tissue thickness.
Źródło:: Nukleonika; 2013, 58, 4; 511-517
0029-5922
1508-5791
Pojawia się w:: Nukleonika
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 24.

Tytuł:: The effect of the heat treatment on the crosslinking of epoxy resin for aviation applications
Wpływ wygrzewania na sieciowanie żywicy epoksydowej przeznaczonej do zastosowań w lotnictwie
Autorzy:: Mucha, Mateusz
Sterzyński, Tomasz
Krzyżak, Aneta
Powiązania:: https://bibliotekanauki.pl/articles/947419.pdf
Data publikacji:: 2020
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:: epoxy resin
heat treatment
crosslinking
aviation
żywica epoksydowa
wygrzewanie
sieciowanie
lotnictwo
Opis:: We have investigated the MGS L285 epoxy laminating resin system, used in aviation applications. A number of tests were carried out, namely Dynamic Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC), tensile testing, three-point bending flexural testing, Charpy impact testing, Shore D hardness, density measurements and Fourier-Transform Infrared spectroscopy (FT-IR). Moreover, the tensile toughness UTT, the brittleness B and the linear isobaric thermal expansivity αL were calculated. The samples were subjected to heat treatment in the temperatures of 50, 60 and 80°C for 15 hours or were stored in room temperature. Glass transition temperature, hardness, density as well as other properties were observed to rise along with the increasing heat treatment temperature, suggesting the validity of applications of Voronoi-Delaunay structural analysis to polymer science. On the other hand, properties such as brittleness, toughness and impact strength exhibited a non-linear course of changes as a function of the heating temperature.
Badano laminującą żywicę epoksydową MGS L285 przeznaczoną do zastosowań w lotnictwie. Przeprowadzono dynamiczną analizę mechaniczną (DMA), skaningową kalorymetrię różnicową (DSC), statyczną próbę rozciągania, zginanie trójpunktowe, badanie młotem Charpy’ego, pomiary twardości metodą Shore’a D, pomiary gęstości, zarejestrowano także widma metodą skaningowej spektroskopii transformatorowej Fouriera (FT-IR). Obliczono wartości wiązkości UTT, kruchości B i izobarycznej rozszerzalności termicznej αL. Próbki wygrzewano w temperaturze 50, 60 lub 80 stopni Celsjusza przez 15 h lub przechowywano w temperaturze pokojowej. W odniesieniu do dużej części badanych właściwości zaobserwowano ich poprawę wraz z rosnącą temperaturą wygrzewania. Korelacja temperatury zeszklenia, twardości i gęstości polimerów wskazuje na słuszność zastosowania w badaniu wolnych objętości analizy strukturalnej opartej na triangulacji Delone i diagramach Woronoja. W wypadku właściwości, takich jak: kruchość, wiązkość i udarność stwierdzono nieliniowy przebieg zmian w funkcji temperatury wygrzewania.
Źródło:: Polimery; 2020, 65, 11-12; 776-783
0032-2725
Pojawia się w:: Polimery
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 25.

Tytuł:: Fotoreaktwne poliakrylanowe kleje samoprzylepne
Photoreactive acrylics pressure-sensitive adhesives
Autorzy:: Kowalska, J.
Czech, Z.
Powiązania:: https://bibliotekanauki.pl/articles/171714.pdf
Data publikacji:: 2016
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: kleje samoprzylepne
kleje fotoreaktywne
sieciowanie
pressure-sensitive adhesives
photoreactive adhesives
crosslinking
Opis:: Pressure-sensitive adhesives (PSAs) are non-metallic materials used to bond other materials, mainly on their surfaces through adhesion and cohesion. Adhesion and cohesion are phenomena, which may be described thermodynamically and chemically, but actually they cannot be measured precisely. It was shown that the most important bonding processes are bonding by adhesion and bonding with pressure- -sensitive adhesives. The difference between pressure-sensitive adhesives and other adhesives, such as contact adhesives, is in the permanent surface stickiness of the pressure-sensitive adhesives before, or after, the application. The fastest developing polymers departments are: initiating UV photopolymerization and photocrosslinking. Ultraviolet radiation (UV) part of the electromagnetic radiation having a wavelength of 100 to 400 nm, the practical use has an area of 200 to 400 nm. UV radiation does not cause visual impressions results in a strongly fluorescence, photoelectric, photochemical reactions and has a high biological activity. It is particularly important industrial use of UV crosslinking which is used in the manufacture of a wide range of self-adhesives, such as assembly lines, labels, decorative films, protective films, patches and biomedical electrode. Especially important critical point during UV-curing is the balance between adhesion and cohesion of the crosslinked pressure-sensitive adhesive layer. An important element is finding the appropriate beneficial relationship between tack, adhesion and cohesion of the crosslinked pressure-sensitive adhesives that offer assurance to their respective industrial applications. Ultraviolet radiation crosslinking is carried out at room temperature and does not require high temperatures, an important disadvantage pressure-sensitive adhesives crosslinked by heat. Compared to systems crosslinked thermally, the use of UV crosslinking process provides greater speed and effective a crosslinking process, and also does not damage the materials with low thermal resistance.
Źródło:: Wiadomości Chemiczne; 2016, 70, 7-8; 541-551
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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