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    Wyświetlanie 1-12 z 12
    Tytuł:
    Thermogravimetry of chitosan with nanofillers
    Autorzy:
    Puchalska, Anna
    Mucha, Maria
    Powiązania:
    https://bibliotekanauki.pl/articles/1035418.pdf
    Data publikacji:
    2011
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    activation energy
    biopolymers
    chitosan
    thermogravimetry
    Opis:
    In the present paper the degradation of chitosan and its blends with hydroxyapatite, nanoclay and nanosilver as well as the impact of those nanofillers added to chitosan on its decomposition at high temperatures are studied. The applied films of thickness 50 μm were obtained by casting the acidic solutions: chitosan and its blends with hydroxyapatite, nanoclay and nanosilver. To mix solutions with nanofillers ultrasounds were applied. To study the thermal degradation we applied thermogravimetry in dynamic and static conditions, which is a method of thermal analysis involving the continuous recording of weight loss Based on experimental data activation energies of thermal decomposition close to a maximum rate loss were calculated using different methods for chitosan and its blends with hydroxyapatite, nanoclay and nanosilver. The addition of three nanofillers mentioned above result in a visual increase of activation energy of thermal degradation process of chitosan due to slower evolution of decomposed gases from chitosan matrix reflected by a slower rate of weight loss.
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2011, 16; 31-42
    1896-5644
    Pojawia się w:
    Progress on Chemistry and Application of Chitin and its Derivatives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Porous chitosan structures for medical applications
    Autorzy:
    Tylman, Michał
    Mucha, Maria
    Powiązania:
    https://bibliotekanauki.pl/articles/1035545.pdf
    Data publikacji:
    2010
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    chitosan scaffolds
    lyophilization
    tissue engineering
    Opis:
    The aim of the study was to develop preparation methods of porous chitosan structures and to investigate their morphological properties as well as the kinetics of model substance release (salicylic acid). Chitosan scaffolds were generated using the liophylisation method and the systems obtained were saturated with hydroxyapatite and salicylic acid. Microscopic investigations (optical and electron microscopy) were carried out to examine the morphology of structures and water vapour sorption isotherms were determined to define the influence of hydroxyapatite on the system sorption ability. Additionally, the kinetic curve for the model substance release process (the process of the 1st order) was determined.
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2010, 15; 97-106
    1896-5644
    Pojawia się w:
    Progress on Chemistry and Application of Chitin and its Derivatives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of nanosilver on thermal stability of chitosan
    Autorzy:
    Białas, Sylwia
    Mucha, Maria
    Powiązania:
    https://bibliotekanauki.pl/articles/1035214.pdf
    Data publikacji:
    2013
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    chitosan
    nanosilver
    thermal degradation
    Opis:
    Nanoadditives for polymers have many valuable features: e.g. the ability to change the properties of polymers: mechanical strength, stability and heat resistance and resistance to radiation. These properties make them an interest in recent years. Studies of polymer composites with nanoadditives leads to discovering more, unique types of nanoadditive interactions on a structure and properties of the polymer. One of the most widely used nanoadditive is nanosilver, which have antibacterial and antifungal properties. An important aspect is thus to investigate the effect of this additive on thermal stability of the polymer composite. The aim of this study was to investigate the effect of nanosilver on the thermal stability and properties of chitosan. Chitosan composites with nanosilver in the form of films with a thickness of 10-30um and the content of silver 0.5 and 1% was obtained by casting. In order to study the thermal stability samples were subjected to a temperature of 120°C (time 0-90h). Studies on influence of nanosilver on the thermal stability of the polymer was performed using infrared spectroscopy (FTIR). This allows to observe changes in the chemical structure of polymer. The changes in the major functional groups was observed: 1420cm-1(bending vibration of -C-H group), 1577cm-1 (bending vibrations of the amine group-NH2), 1655cm-1 (vibrations of C=O in amide group). Mechanical strength test of chitosan composites subjected to high temperature was also performed. Tensile tests (using the Instron 5325 apparatus) were conducted to determine changes in values of Young's modulus, maximum stress and elongation at break. The study showed an effect of the presence of nanosilver on the structural and mechanical properties of chitosan. Nanosilver improves the thermal stability of studied functional groups of chitosan.
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2013, 18, 18; 85-92
    1896-5644
    Pojawia się w:
    Progress on Chemistry and Application of Chitin and its Derivatives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Electrolytic method for obtaining porous chitosan structures with hydroxyapatit
    Autorzy:
    Tylman, Michał
    Mucha, Maria
    Powiązania:
    https://bibliotekanauki.pl/articles/1035430.pdf
    Data publikacji:
    2011
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    HAp
    chitosan
    electrolysis
    electrolytic conductivity
    Opis:
    The aim of this study was to develop a preparation method of porous chitosan structures, in the electrolysis of the chitosan solution in acetic acid. Chitosan in aqueous acetic acid is a polyelectrolyte. During the constant flow of electric current through this system, pure chitosan begins to accumulate on an anode, in the form of porous hydrogel layers. The addition of hydroxyapatite (HAp) to the electrolyte enhances the process and allows for obtaining spatially arranged complex structures of chitosan.
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2011, 16; 5-14
    1896-5644
    Pojawia się w:
    Progress on Chemistry and Application of Chitin and its Derivatives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Chitosan applied for gypsum modification
    Autorzy:
    Mucha, Maria
    Mróz, Patrycja
    Wrona, Dominika
    Powiązania:
    https://bibliotekanauki.pl/articles/1034560.pdf
    Data publikacji:
    2017
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    chitosan/PVA
    gypsum
    mechanical properties
    morphology
    setting time
    Opis:
    In order to improve the properties of gypsum materials, including workability, mechanical strength and ability to retain water, various admixtures (also polymers), known as plasticisers, have been applied. These polymers can be soluble in water, such as cellulose and starch ethers, or unsoluble applied in a form of dispersion up to 5% of weight fraction. The admixtures are added into initial water and mixed with hemihydrate calcium sulphate in a proper ratio. In the hydration process of the hemihydrate into dehydrate, a crystallisation process leading to gypsum setting occurs. In the present work, a chitosan sample of DD=85% in two forms was applied: dissolved in 1% acetic acid and as a water dispersion in the weight fraction up to 1% of the gypsum matrix. The water to gypsum ratios of 0.6 or 0.74 was applied. The influence of chitosan on the rate of setting and kinetics of crystallisation of gypsum was investigated and discussed. The morphological structure of the resulting gypsum sample was examined using SEM microscopy. In the presented results, chitosan in the form of a 1% dispersion was a setting retardant and it changed the morphological structure of gypsum. However, mechanical tests showed a decrease of bending strength. When chitosan was applied as a biomaterial, the chitosan content in the composite was equal to 10%, and thus a compressing strength increased. The presence of PVA (polyvinyl alcohol) in the gypsum matrix caused a small effect on gypsum setting in contrast to PVAc (polyvinyl acetate), which is a good admixture for both cement and gypsum [2,3].
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2017, 22; 166-175
    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:
    Modified dibutyrylchitin films as matrices for controlled ibuprofen release
    Autorzy:
    Mucha, Maria
    Michalak, Iwona
    Draczyński, Zbigniew
    Powiązania:
    https://bibliotekanauki.pl/articles/1035223.pdf
    Data publikacji:
    2013
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    controlled release
    dibutyrylchitin
    ibuprofen
    nanoclay
    transdermal systems
    Opis:
    In view of ongoing interest in biodegradable polymers, dibutyrylchitin was used as a matrix for controlled release of a model substance. Transdermal systems (films) are presently more commonly used as an alternative to standard forms of drug delivery. The presented results are concerned with the release of ibuprofen from dibutyrylchitin film. The obtained transdermal films were modified by applying a control layer to slow down the release process. The matrices were also modified by adding nanoclay (Nanofil 2). Dibutyrylchitin matrices were tested for swelling and release kinetics using UV-Vis spectrophotometer. The drug kinetics release was studied in phosphorus buffer of pH=5.5 at the temperature of 35˚C. Structural investigations of the obtained matrices were carried out by optical microscopy and FTIR spectrophotometry. An appropriate mathematical model was also fitted to the obtained experimental data
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2013, 18, 18; 139-147
    1896-5644
    Pojawia się w:
    Progress on Chemistry and Application of Chitin and its Derivatives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Chitosan/poly(vinyl alcohol) hydrogels as controlled drug delivery systems
    Autorzy:
    Kocemba, Aleksandra
    Mucha, Maria
    Powiązania:
    https://bibliotekanauki.pl/articles/1034608.pdf
    Data publikacji:
    2017
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    chitosan/PVA hydrogel
    gentamicin
    glutaraldehyde
    release kinetics
    swelling
    Opis:
    In order to achieve hydrogel and drug release profiles, a comprehensive knowledge of the types, properties and syntheses of hydrogel polymer networks are needed. For this reason, a natural biopolymer hydrogel based on chitosan was described. Chitosan has many advantages, which meet the requirements necessary for the preparation of medical materials; for example, wound dressings. This article focused on the biomedical use of a chitosan hydrogel: chitosan–poly(vinyl alcohol) (PVA). The method of preparation of hydrogels containing a drug as an active wound dressing was described. To obtain a hydrogel dressing to be applied in patients with burns or difficult curative wounds, gentamicin (an aminoglycoside antibiotic) was used as a medicament. The effect of the PVA concentration in hydrogels on the release rate of the antibiotic was examined. For this, the crosslinking agent of the hydrogel, glutaraldehyde, was used. The release process of gentamicin was described by using an equation of first order kinetics.
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2017, 22; 97-105
    1896-5644
    Pojawia się w:
    Progress on Chemistry and Application of Chitin and its Derivatives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of model drug release kinetics from complex matrices of polylactide-chitosan
    Autorzy:
    Balcerzak, Jacek
    Mucha, Maria
    Powiązania:
    https://bibliotekanauki.pl/articles/1035492.pdf
    Data publikacji:
    2010
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    chitosan
    kinetics
    polylactide
    polymer composite
    prolonged release
    Opis:
    In the present paper the Authors analyse the experimental results of a model drug (ibuprofen) release approximated with three commonly used semi-empirical models: Korsmeyer-Peppas, first order kinetics and Gallagher-Corrigan equation. Drug carriers in the form of films composed of chitosan matrix and polylactide microparticles were produced by ultrasonic emulsification with solvent evaporation followed by film casting technique. Additionally, polylactide shield layers (5μm thick) were attached to both sides of obtained films by means of spray-coating process. A microscopic analysis confirmed the uniform distribution of polylactide microparticles (diameter: 1-2 μm) within chitosan films. Based on the of microscopic study, molecular drug dispersion within composite matrices was found. Fraction of ibuprofen released into medium of pH equal to 1.4 or 7.2 (GI tract) was measured by means of UV-VIS spectrophotometry. The finest approximation was obtained by fitting two-stage release model derived by K. M. Gallagher and O. I. Corrigan to the release data. Analysis of model parameters led to the conclusion that the increase of composite films thickness as well as weight fraction of PLA microparticles within films prolong drug release.
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2010, 15; 117-126
    1896-5644
    Pojawia się w:
    Progress on Chemistry and Application of Chitin and its Derivatives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Kinetics of active substance release from flat biopolymer multilayer films
    Autorzy:
    Michalak, Iwona
    Traczyk, Dariusz
    Mucha, Maria
    Powiązania:
    https://bibliotekanauki.pl/articles/1035524.pdf
    Data publikacji:
    2010
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    chitosan
    drug release
    polylactid
    polymer films
    swelling kinetics
    Opis:
    Abstract. Polymer films were made of different biodegradable materials. Solid support of model active substance (salicylic acid) was unmodified and modified (crosslinked with glutaraldehyde) chitosan and outside layers were polylactid acid (PLA). The aim of the study was to obtain the controlled release kinetics of active substance, in medium of pH 5.6 which is similar to conditions occurring on the human skin surface. The chitosan films were investigated with swelling kinetics while multilayer films were studied with release kinetics of active substance (salicylic acid). The amount of salicylic acid released from film was measured using a UV-VIS spectrophotometer. The appropriate mathematical model was also adjusted to the experimental points. The results prove that the swelling process follows the first order kinetics but the results of release process are fitted with Peppas model.
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2010, 15; 107-116
    1896-5644
    Pojawia się w:
    Progress on Chemistry and Application of Chitin and its Derivatives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermal stability of chitosan nanocomposites containing tio2 and organo-modified montmorillonite
    Autorzy:
    Książek, Sylwia
    Mucha, Maria
    Powiązania:
    https://bibliotekanauki.pl/articles/1034832.pdf
    Data publikacji:
    2015
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    chitosan
    organo-modified montmorillonite
    thermal degradation
    titanium dioxide nanoparticles
    Opis:
    The aim of this work was to investigate the effect of different nanoparticles (TiO2 and organically modified montmorillonite MMT) on thermal stability of chitosan thin films (obtained by casting) and to compare with previously studied- CuO and Ag effect. Thermal degradation was carried out in air atmosphere at 140°C up to 100 hours. Various functional groups of chitosan have a different susceptibility to degradation. The influence of nanoparticles amount on degradation of selected structural groups of chitosan was calculated. It was proved, that elongation at break of chitosan sample and its nanocomposites with TiO2 and organically modified montmorillonite decrease rapidly after 20h of thermal degradation. Moreover, as is clear from FTIR studies, that TiO2 nanoparticles enhance the resistant of the -C-O-C- bond responsible for chain scission of chitosan due to thermal degradation. An opposite effect is observed in a case of MMT, where the chain scission of -C-O-C- bond is higher than for pure chitosan. Another effect of nanoparticles are observed in destruction of unstable amine group (-NH3 band at 1560 cm-1) and formation of the amide group (band at 1650 cm-1). In this case both nanoadditives accelerate the decomposition of amine group and the formation of amide group in higher extent in comparison to pure chitosan.
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2015, 20; 122-129
    1896-5644
    Pojawia się w:
    Progress on Chemistry and Application of Chitin and its Derivatives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Salicylic acid release from chitosan pellets coated with polylactide
    Autorzy:
    Mucha, Maria
    Balcerzak, Jacek
    Filipiak, Adam
    Powiązania:
    https://bibliotekanauki.pl/articles/1035411.pdf
    Data publikacji:
    2011
    Wydawca:
    Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
    Tematy:
    chitosan
    first order kinetics
    polylactide
    prolonged drug release
    salicylic acid
    Opis:
    The aim of the study was to prepare a bi-polymer drug carrier composed of chitosan pellets (CS) coated with polylactide shell (PLA) providing prolonged model drug – salicylic acid (SA) release into phosphate buffer of pH = 7.2. Pellets were obtained through a coacervation followed by a freeze-drying process. In a terms of model drug loading, porous pellets were impregnated with a SA solution under vacuum. Afterwards, loaded and dried beads were coated with PLA films through their dipping in a PLA organic solution. FTIR spectroscopy was implemented to analyse the efectiveness of SA loading process. The UV-Vis spectrophotometry kinetic studies of a model drug release from PLA coated and non-coated pellets into phosphate buffer were conducted. Increasing time of CS pellets impregnation with SA solution resulted in decrease of salicylic acid release rate.This tendency was more evident for the SA release from pellets coated with an additional layer of PLA. Model drug release kinetic points were well approximated with first order kinetics model.
    Źródło:
    Progress on Chemistry and Application of Chitin and its Derivatives; 2011, 16; 79-88
    1896-5644
    Pojawia się w:
    Progress on Chemistry and Application of Chitin and its Derivatives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-12 z 12

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