This paper presents a simple method of obtaining a bacterial cellulose (BC) composite with the ad... more This paper presents a simple method of obtaining a bacterial cellulose (BC) composite with the addition of graphene oxide (GO) using an in situ method and studies the influence of GO nanoparticles on the structure and properties of the obtained membranes. Microorganisms obtained from Golden Delicious apple vinegar were used to obtain the BC. During the biosynthesis, GO was introduced in the amounts of 3.7, 5.4 and 7.1% w/w. The resulting BC/GO composite was characterized by high water content (~400%), a thickness of about 1.1 mm (in wet form) and a cellulose nanofiber diameter of ~100 nm. The possibility of using the resulting composite membranes as potential active dressings with the sustained-release analgesic medicine—paracetamol—was investigated. The BC/GO composite membranes were characterized by a medicine sorption of 60 mg/g of BC, a slow desorption time, a constant medicine concentration over time and an 80% paracetamol release rate after 24 h. The morphology of membrane sur...
Graphene and its derivatives, such as graphene oxide (GO) or reduced graphene oxide (rGO), due to... more Graphene and its derivatives, such as graphene oxide (GO) or reduced graphene oxide (rGO), due to their properties, have been enjoying great interest for over two decades, particularly in the context of additive manufacturing (AM) applications in recent years. High-impact polystyrene (HIPS) is a polymer used in 3D printing technology due to its high dimensional stability, low cost, and ease of processing. However, the ongoing development of AM creates the need to produce modern feedstock materials with better properties and functionality. This can be achieved by introducing reduced graphene oxide into the polymer matrix. In this study, printable composite filaments were prepared and characterized in terms of morphology and thermal and mechanical properties. Among the obtained HIPS/rGO composites, the filament containing 0.5 wt% of reduced graphene oxide had the best mechanical properties. Its tensile strength increased from 19.84 to 22.45 MPa, for pure HIPS and HIPS-0.5, respectivel...
Polish Journal of Materials and Environmental Engineering, 2021
As part of the research, chitin materials were obtained using the electrospinning method. For thi... more As part of the research, chitin materials were obtained using the electrospinning method. For this purpose, chitin solutions were prepared in phosphoric acid and lithium chloride in an amide solvent. The coagulation of chitin materials was performed in alkaline water baths and in distilled water. As a result of the method, microspheres and microfibers of chitin were obtained. The morphological structure of the obtained materials was analyzed using a scanning electron microscope (SEM) and an optical microscope. The obtained microspheres were characterized by a similar diameter value, amounting to 195 μm. In contrast, chitin microfibers from 90 to 150 μm. The obtained materials were subjected to mid-infrared and Raman spectrophotometric tests in order to determine the influence of the solvents used on the chemical structure of native and regenerated chitin. Infrared spectroscopy studies confirmed no changes in the chemical structure of regenerated chitin. Raman spectroscopy studies confirmed no degradation of regenerated chitin. In the spectra obtained, differences were observed in the form of changes in the shape of the bands for oscillators be associated in intermolecular interactions, which is caused by changes in the supermolecular structure.
This paper presents the results of studies on the preparation of cellulosic membranes, from a sol... more This paper presents the results of studies on the preparation of cellulosic membranes, from a solution in 1-ethyl-3- methylimidazolium acetate (EMIMAc), using the phase inversion method. Initially, the membranes were obtained by coagulation of the polymer film in water and primary alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol), 1-hexanol, 1-octanol) resulting in membranes with significantly differing morphologies. Subsequently, composite membranes were produced, with the support layer being a membrane with the largest pores, and the skin layer a membrane with smaller pores. The resulting membranes were tested for physicochemical and transport properties. The morphology of the membrane surfaces and their cross-sections were investigated by using a scanning electron microscope (SEM). The structure of the membranes, on the other hand, was investigated by FTIR spectroscopy and WAXS structural analysis.
In the previous paper [1], some results of studies on microcrystalline chitosan (MCCh) biodegrada... more In the previous paper [1], some results of studies on microcrystalline chitosan (MCCh) biodegradation in an aqueous medium were presented. Two forms of MCCh samples were analysed, films and lyophilizates. The dependence of biodegradation rate on the temperature ranging from 20°C to 50°C was examined. It transpired from the above studies that total degradation of MCCh (both in the form of a film and of a lyophilizate) takes Studies on the Biodegradation of Chitosan in an Aqueous Medium Maria Ratajska, Grażyna Strobin, Maria Wiśniewska-Wrona, Danuta Ciechańska, Henryk Struszczyk, Stefan Boryniec*, Dorota Biniaś*, Włodzimierz Biniaś*
The aim of this interdisciplinary study was to answer the question of whether active antioxidants... more The aim of this interdisciplinary study was to answer the question of whether active antioxidants as graphene oxide (GO), sodium ascorbate, and L-ascorbic acid modify at a molecular and supramolecular level the tissue of pathological amnion and the necrotic eschar degraded in thermal burn. We propose new solutions of modifiers based on GO that will become innovative ingredients to be used in transplants (amnion) and enhance regeneration of epidermis degraded in thermal burn. Methods: A Nicolet 6700 spectrophotometer with Omnic software and the EasiDiff diffusion accessory were used in FTIR spectroscopic analysis. A Nicolet Magna-IR 860 spectrometer with an FT Raman accessory was used to record the Raman spectra of the samples. The surface of the samples was examined using a Phenom ProX scanning electron microscope with an energy-dispersive X-ray spectroscopy detector to diagnose and illustrate morphological effects on skin and amnion samples. SAXS measurements were carried out with a compact Kratky camera equipped with the SWAXS optical system. Results: Characterisation of amide I-III regions, important for molecular structure, on both FTIR and FTR spectra revealed distinct shifts, testifying to organization of protein structure after GO modification. A wide lipid band associated with ester-group vibrations in phospholipids of cell membranes and vibrations of the carbonyl group of GO in the 1,790-1,720 cm -1 band were observed in the spectra of thermally degraded and GO-modified epidermis and pathological amnion. SAXS studies revealed that GO caused a significant change in the structure of the burnt skin, but its influence on the structure of the amnion was weak. Conclusion: Modification of burn-damaged epidermis and pathological amnion by means of GO results in stabilization and regeneration of tissue at the level of molecular (FTIR, FTR) and supramolecular (SAXS) interactions.
The existence of the third, transition component, apart from the crystalline and amorphous phases... more The existence of the third, transition component, apart from the crystalline and amorphous phases, in polyethylenes has already been proved in several papers. In this work, the WAXS patterns of polyethylenes with various branch contents were analysed, aiming at the best method of accounting for the third phase in the procedure of decomposition of the patterns into crystalline peaks and amorphous scattering. It appeared that the best result was obtained when we assumed that the intermediate phase is represented by two peaks located close to the crystalline reflections (110) and (200), on the left sides of these reflections. The calculations performed have shown that both the density and the mass fraction of this intermediate third phase decrease continuously with increasing 1-octene content. A comparison of the mass fractions of the three phases has shown that the total mass fractions of the crystalline and transition phases determined with the WAXS and Raman methods coincide very we...
A method of measuring fibre humidity, which allows for investigation of very small masses of samp... more A method of measuring fibre humidity, which allows for investigation of very small masses of samples (in the milligram range) using typical FTIR spectrophotometers has been developed. The method is based on measuring, the proportion of bands coming from water in a liquid state and those from the fibre substance with near-infra-red spectra. The quantitative proportionality of the peak area in relation to the water content permits to find a simple relationship which describes the humidity of the samples to be established.
University of Bielsko-Biala, Faculty of Textile Engineering and Environmental Protection, Institu... more University of Bielsko-Biala, Faculty of Textile Engineering and Environmental Protection, Institute of Textile Engineering and Polymer Materials ul. Willowa 2, 43-309 Bielsko-Biala, Poland; e-mail: [email protected] Abstract This work describes a method of formation of microfibres from cellulose acetate butyrate solution in acetone by electrospinning. The method used a specially designed electrospinning reactor with an arrangement generating low-temperature plasma incorporated in the spinning zone. In this study the low-temperature plasma treatment was used to modify the surface of cellulose acetate butyrate fibres. The chemical nature of the microfibres’ surfaces was examined by UV-Vis spectroscopy with the use of an integration sphere and reflectance FTIR spectroscopy. Scanning electron microscopy (SEM) was used to determine the morphology and size of the electrospun fibres modified in low-temperature plasma and to compare them with the unmodified fibres.
University of Bielsko-Biala, Faculty of Materials and Environment Science, Institute of Textile E... more University of Bielsko-Biala, Faculty of Materials and Environment Science, Institute of Textile Engineering and Polymer Materials, ul. Willowa 2, 43-309 Bielsko-Biala, Poland E-mail: [email protected] Abstract A spectroscopic method of determining cellulose content in cotton blends has been described. It is part of a wider project to develop spectroscopic methods of analysing textile blends. The method does not require using hazardous high-quality chemicals or time-consuming preparatory work and it reduces the time needed to determine the content to barely a few minutes.
Low-temperature plasma (LTP) is produced almost exclusively in glow discharges in a gaseous envir... more Low-temperature plasma (LTP) is produced almost exclusively in glow discharges in a gaseous environment. A key property of this type of plasma is the lack of equilibrium between the temperature of the electrons and the energy of the un-ionised gas particles. This allows the creation of conditions in which the temperature of the plasma gas remains close to that of the environment, while the energy of the electrons is sufficient to break intermolecular and covalent bonds. This property of LTP makes it useful for initiating modifications in polymers which are not resistant to high temperatures, that is, of almost all fibre-forming polymers [1-3].
The paper describes a method of modifying a commercial viscose nonwoven fabric and its use as a m... more The paper describes a method of modifying a commercial viscose nonwoven fabric and its use as a modern mulching material in agriculture. The conducted research confirmed that the proposed modification of the viscose nonwoven fabric could be successfully used as a multipurpose and, above all, completely biodegradable nonwoven crop cover, which will eliminate the problem of disposal after the harvest period. Modified cellulose nonwoven fabric was obtained by staining with NB—BT helion brown, then padding with potassium nitrate (KNO3) solution (used as a fertilizer) and finally coating with polylactide (PLA) solution. The characterisation of the nonwoven fabric included structural analysis, physicochemical properties and mechanical tests. The modified cellulose nonwovens were used in the tunnel cultivation of tomatoes as a heat-retardant, water-absorbing, antiweed mulching material that prevents soil infestation and slowly releases fertilizers.
Reduced graphene oxide (rGO) was used to obtain Polystyrene (PS)/rGO nanocomposites via in-situ s... more Reduced graphene oxide (rGO) was used to obtain Polystyrene (PS)/rGO nanocomposites via in-situ suspension polymerization. The main goal of the article was to determine how rGO influences the morphology and thermal properties of PS beads. The obtained samples were studied by means of a scanning electron microscope (SEM), and calorimetric and thermogravimetric analysis (DCS, TGA). It was proven that the addition of rGO, due to the presence of polar functional groups, causes significant changes in bead sizes and size distribution, and in their morphology (on the surface and in cross-section). The increasing amount of rGO in the polymer matrix increased the size of beads from 0.36 to 3.17 mm for pure PS and PS with 0.2 wt% rGO content, respectively. PS/rGO nanocomposites are characterized by distinctly improved thermostability, which is primarily expressed in the increase in their decomposition temperature. For a sample containing 0.3 wt% rGO, the difference is more than 12 °C in compa...
ABSTRACT The paper presents the structural studies of mineralized chitosan hydrogels. Hydrogels p... more ABSTRACT The paper presents the structural studies of mineralized chitosan hydrogels. Hydrogels produced by using sodium beta-glycerophosphate (Na-β-GP) as a neutralizing agent. Mineralization was performed method “post loading”, which consisted in sorption to the gels structure Ca ions. In order to obtain – in the structure of gels – compounds similar to the hydroxyapatites present naturally in bone tissue, gels after sorption were modified in: pH 7 buffer and sodium hydrogen phosphate. In order to determine the structural properties of the gels, the following methods were used: infrared spectroscopy with Fourier transformation, FTIR, X-ray diffractometry, XRD, scanning electron microscopy, SEM.
Changes in structure of dibutyrylchitin fibres in the process of chitin regeneration Summary -Dib... more Changes in structure of dibutyrylchitin fibres in the process of chitin regeneration Summary -Dibutyrylchitin (DBCH) fibres were formed from the solution of the polymer in and anhydrous ethyl alcohol. The fibres obtained were then treated with a 5 % aq. potassium hydroxide solution at temperatures ranging from 20 o C to 90 o C. The process of chitin regeneration was carried out gradually and its rate depended on the temperature. High temperature alkaline treatment causes that the transformation of DBCH fibres into fibres of regenerated chitin becomes more effective. Molecular and supermolecular structural changes of fibres were examined by wide angle X-ray diffraction (WAXS), FT-IR spectroscopy and Raman spectroscopy. The obtained diffractograms were analyzed using Hindeleh and Johnson method and the computer programme "Optifit" in which Rosenbrock method was applied. The analysis of WAXS diffraction patterns showed that the curve obtained for regenerated chitin is similar to the curve obtained for the native krill chitin. The analysis of FT-IR spectra proved that as a result of hydrolysis of DBCH fibres the transformation of DBCH into chitin took place and chemical structure of the obtained chitin was almost the same as the structure of the initial native chitin.
Progress on Chemistry and Application of Chitin and its Derivatives, Sep 30, 2017
In this study, a solution of dibutyrylchitin (DBC)/polylactide (PLA) blend micro and nanofibres w... more In this study, a solution of dibutyrylchitin (DBC)/polylactide (PLA) blend micro and nanofibres were successfully fabricated using blends of 2,2,2-trifluoroethanol (TFE) as solvents. Fibres were produced from the solutions by electrospinning. The DBC/PLA blend solutions in various ratios were studied for electrospinning into micro/nanofibres. The morphology of the micro and nanofibres was observed by scanning electron microscope (SEM). The biggest diameters of DBC/PLA fibres were obtained for the blended microfibres in ratios of 10/90 and 25/75. The smallest diameter was observed for pure polymers. The antibacterial properties were examined for materials obtained by electrospinning. In the experiments, materials with antibacterial properties were made. It is likely that the electrospun micro and nanofibres will be used in the native extracellular matrix for tissue engineering.
The article presents a new fabrication method for bioactive fibres with a microporous structure o... more The article presents a new fabrication method for bioactive fibres with a microporous structure of ethylene–vinyl alcohol copolymers (EVOH)/ethylene−propylene copolymer (EPC) blends. The experimental work carried out resulted in obtaining EVOH/EPC polymer blends fibres with the addition of glycerol and sodium stearate. Different concentrations of glycerol (38%, 32%) and sodium stearate (2%, 8%) were used to prepare the fibres. The purpose of using different concentrations of stearate and glycerol was to evaluate the effect of additives on the structure and properties of the fibres. A significant influence of the additives used on the morphological structure of the fibres was found. The resulting fibres were modified with an AgNO3 solution and reduced to silver nanoparticles (AgNPs), to give the fibres bioactive properties. The fibres obtained with the addition of 8% stearate have a more developed surface, which may influence the amount of adsorbed silver particles inside the fibre. ...
This paper presents a simple method of obtaining a bacterial cellulose (BC) composite with the ad... more This paper presents a simple method of obtaining a bacterial cellulose (BC) composite with the addition of graphene oxide (GO) using an in situ method and studies the influence of GO nanoparticles on the structure and properties of the obtained membranes. Microorganisms obtained from Golden Delicious apple vinegar were used to obtain the BC. During the biosynthesis, GO was introduced in the amounts of 3.7, 5.4 and 7.1% w/w. The resulting BC/GO composite was characterized by high water content (~400%), a thickness of about 1.1 mm (in wet form) and a cellulose nanofiber diameter of ~100 nm. The possibility of using the resulting composite membranes as potential active dressings with the sustained-release analgesic medicine—paracetamol—was investigated. The BC/GO composite membranes were characterized by a medicine sorption of 60 mg/g of BC, a slow desorption time, a constant medicine concentration over time and an 80% paracetamol release rate after 24 h. The morphology of membrane sur...
Graphene and its derivatives, such as graphene oxide (GO) or reduced graphene oxide (rGO), due to... more Graphene and its derivatives, such as graphene oxide (GO) or reduced graphene oxide (rGO), due to their properties, have been enjoying great interest for over two decades, particularly in the context of additive manufacturing (AM) applications in recent years. High-impact polystyrene (HIPS) is a polymer used in 3D printing technology due to its high dimensional stability, low cost, and ease of processing. However, the ongoing development of AM creates the need to produce modern feedstock materials with better properties and functionality. This can be achieved by introducing reduced graphene oxide into the polymer matrix. In this study, printable composite filaments were prepared and characterized in terms of morphology and thermal and mechanical properties. Among the obtained HIPS/rGO composites, the filament containing 0.5 wt% of reduced graphene oxide had the best mechanical properties. Its tensile strength increased from 19.84 to 22.45 MPa, for pure HIPS and HIPS-0.5, respectivel...
Polish Journal of Materials and Environmental Engineering, 2021
As part of the research, chitin materials were obtained using the electrospinning method. For thi... more As part of the research, chitin materials were obtained using the electrospinning method. For this purpose, chitin solutions were prepared in phosphoric acid and lithium chloride in an amide solvent. The coagulation of chitin materials was performed in alkaline water baths and in distilled water. As a result of the method, microspheres and microfibers of chitin were obtained. The morphological structure of the obtained materials was analyzed using a scanning electron microscope (SEM) and an optical microscope. The obtained microspheres were characterized by a similar diameter value, amounting to 195 μm. In contrast, chitin microfibers from 90 to 150 μm. The obtained materials were subjected to mid-infrared and Raman spectrophotometric tests in order to determine the influence of the solvents used on the chemical structure of native and regenerated chitin. Infrared spectroscopy studies confirmed no changes in the chemical structure of regenerated chitin. Raman spectroscopy studies confirmed no degradation of regenerated chitin. In the spectra obtained, differences were observed in the form of changes in the shape of the bands for oscillators be associated in intermolecular interactions, which is caused by changes in the supermolecular structure.
This paper presents the results of studies on the preparation of cellulosic membranes, from a sol... more This paper presents the results of studies on the preparation of cellulosic membranes, from a solution in 1-ethyl-3- methylimidazolium acetate (EMIMAc), using the phase inversion method. Initially, the membranes were obtained by coagulation of the polymer film in water and primary alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol), 1-hexanol, 1-octanol) resulting in membranes with significantly differing morphologies. Subsequently, composite membranes were produced, with the support layer being a membrane with the largest pores, and the skin layer a membrane with smaller pores. The resulting membranes were tested for physicochemical and transport properties. The morphology of the membrane surfaces and their cross-sections were investigated by using a scanning electron microscope (SEM). The structure of the membranes, on the other hand, was investigated by FTIR spectroscopy and WAXS structural analysis.
In the previous paper [1], some results of studies on microcrystalline chitosan (MCCh) biodegrada... more In the previous paper [1], some results of studies on microcrystalline chitosan (MCCh) biodegradation in an aqueous medium were presented. Two forms of MCCh samples were analysed, films and lyophilizates. The dependence of biodegradation rate on the temperature ranging from 20°C to 50°C was examined. It transpired from the above studies that total degradation of MCCh (both in the form of a film and of a lyophilizate) takes Studies on the Biodegradation of Chitosan in an Aqueous Medium Maria Ratajska, Grażyna Strobin, Maria Wiśniewska-Wrona, Danuta Ciechańska, Henryk Struszczyk, Stefan Boryniec*, Dorota Biniaś*, Włodzimierz Biniaś*
The aim of this interdisciplinary study was to answer the question of whether active antioxidants... more The aim of this interdisciplinary study was to answer the question of whether active antioxidants as graphene oxide (GO), sodium ascorbate, and L-ascorbic acid modify at a molecular and supramolecular level the tissue of pathological amnion and the necrotic eschar degraded in thermal burn. We propose new solutions of modifiers based on GO that will become innovative ingredients to be used in transplants (amnion) and enhance regeneration of epidermis degraded in thermal burn. Methods: A Nicolet 6700 spectrophotometer with Omnic software and the EasiDiff diffusion accessory were used in FTIR spectroscopic analysis. A Nicolet Magna-IR 860 spectrometer with an FT Raman accessory was used to record the Raman spectra of the samples. The surface of the samples was examined using a Phenom ProX scanning electron microscope with an energy-dispersive X-ray spectroscopy detector to diagnose and illustrate morphological effects on skin and amnion samples. SAXS measurements were carried out with a compact Kratky camera equipped with the SWAXS optical system. Results: Characterisation of amide I-III regions, important for molecular structure, on both FTIR and FTR spectra revealed distinct shifts, testifying to organization of protein structure after GO modification. A wide lipid band associated with ester-group vibrations in phospholipids of cell membranes and vibrations of the carbonyl group of GO in the 1,790-1,720 cm -1 band were observed in the spectra of thermally degraded and GO-modified epidermis and pathological amnion. SAXS studies revealed that GO caused a significant change in the structure of the burnt skin, but its influence on the structure of the amnion was weak. Conclusion: Modification of burn-damaged epidermis and pathological amnion by means of GO results in stabilization and regeneration of tissue at the level of molecular (FTIR, FTR) and supramolecular (SAXS) interactions.
The existence of the third, transition component, apart from the crystalline and amorphous phases... more The existence of the third, transition component, apart from the crystalline and amorphous phases, in polyethylenes has already been proved in several papers. In this work, the WAXS patterns of polyethylenes with various branch contents were analysed, aiming at the best method of accounting for the third phase in the procedure of decomposition of the patterns into crystalline peaks and amorphous scattering. It appeared that the best result was obtained when we assumed that the intermediate phase is represented by two peaks located close to the crystalline reflections (110) and (200), on the left sides of these reflections. The calculations performed have shown that both the density and the mass fraction of this intermediate third phase decrease continuously with increasing 1-octene content. A comparison of the mass fractions of the three phases has shown that the total mass fractions of the crystalline and transition phases determined with the WAXS and Raman methods coincide very we...
A method of measuring fibre humidity, which allows for investigation of very small masses of samp... more A method of measuring fibre humidity, which allows for investigation of very small masses of samples (in the milligram range) using typical FTIR spectrophotometers has been developed. The method is based on measuring, the proportion of bands coming from water in a liquid state and those from the fibre substance with near-infra-red spectra. The quantitative proportionality of the peak area in relation to the water content permits to find a simple relationship which describes the humidity of the samples to be established.
University of Bielsko-Biala, Faculty of Textile Engineering and Environmental Protection, Institu... more University of Bielsko-Biala, Faculty of Textile Engineering and Environmental Protection, Institute of Textile Engineering and Polymer Materials ul. Willowa 2, 43-309 Bielsko-Biala, Poland; e-mail: [email protected] Abstract This work describes a method of formation of microfibres from cellulose acetate butyrate solution in acetone by electrospinning. The method used a specially designed electrospinning reactor with an arrangement generating low-temperature plasma incorporated in the spinning zone. In this study the low-temperature plasma treatment was used to modify the surface of cellulose acetate butyrate fibres. The chemical nature of the microfibres’ surfaces was examined by UV-Vis spectroscopy with the use of an integration sphere and reflectance FTIR spectroscopy. Scanning electron microscopy (SEM) was used to determine the morphology and size of the electrospun fibres modified in low-temperature plasma and to compare them with the unmodified fibres.
University of Bielsko-Biala, Faculty of Materials and Environment Science, Institute of Textile E... more University of Bielsko-Biala, Faculty of Materials and Environment Science, Institute of Textile Engineering and Polymer Materials, ul. Willowa 2, 43-309 Bielsko-Biala, Poland E-mail: [email protected] Abstract A spectroscopic method of determining cellulose content in cotton blends has been described. It is part of a wider project to develop spectroscopic methods of analysing textile blends. The method does not require using hazardous high-quality chemicals or time-consuming preparatory work and it reduces the time needed to determine the content to barely a few minutes.
Low-temperature plasma (LTP) is produced almost exclusively in glow discharges in a gaseous envir... more Low-temperature plasma (LTP) is produced almost exclusively in glow discharges in a gaseous environment. A key property of this type of plasma is the lack of equilibrium between the temperature of the electrons and the energy of the un-ionised gas particles. This allows the creation of conditions in which the temperature of the plasma gas remains close to that of the environment, while the energy of the electrons is sufficient to break intermolecular and covalent bonds. This property of LTP makes it useful for initiating modifications in polymers which are not resistant to high temperatures, that is, of almost all fibre-forming polymers [1-3].
The paper describes a method of modifying a commercial viscose nonwoven fabric and its use as a m... more The paper describes a method of modifying a commercial viscose nonwoven fabric and its use as a modern mulching material in agriculture. The conducted research confirmed that the proposed modification of the viscose nonwoven fabric could be successfully used as a multipurpose and, above all, completely biodegradable nonwoven crop cover, which will eliminate the problem of disposal after the harvest period. Modified cellulose nonwoven fabric was obtained by staining with NB—BT helion brown, then padding with potassium nitrate (KNO3) solution (used as a fertilizer) and finally coating with polylactide (PLA) solution. The characterisation of the nonwoven fabric included structural analysis, physicochemical properties and mechanical tests. The modified cellulose nonwovens were used in the tunnel cultivation of tomatoes as a heat-retardant, water-absorbing, antiweed mulching material that prevents soil infestation and slowly releases fertilizers.
Reduced graphene oxide (rGO) was used to obtain Polystyrene (PS)/rGO nanocomposites via in-situ s... more Reduced graphene oxide (rGO) was used to obtain Polystyrene (PS)/rGO nanocomposites via in-situ suspension polymerization. The main goal of the article was to determine how rGO influences the morphology and thermal properties of PS beads. The obtained samples were studied by means of a scanning electron microscope (SEM), and calorimetric and thermogravimetric analysis (DCS, TGA). It was proven that the addition of rGO, due to the presence of polar functional groups, causes significant changes in bead sizes and size distribution, and in their morphology (on the surface and in cross-section). The increasing amount of rGO in the polymer matrix increased the size of beads from 0.36 to 3.17 mm for pure PS and PS with 0.2 wt% rGO content, respectively. PS/rGO nanocomposites are characterized by distinctly improved thermostability, which is primarily expressed in the increase in their decomposition temperature. For a sample containing 0.3 wt% rGO, the difference is more than 12 °C in compa...
ABSTRACT The paper presents the structural studies of mineralized chitosan hydrogels. Hydrogels p... more ABSTRACT The paper presents the structural studies of mineralized chitosan hydrogels. Hydrogels produced by using sodium beta-glycerophosphate (Na-β-GP) as a neutralizing agent. Mineralization was performed method “post loading”, which consisted in sorption to the gels structure Ca ions. In order to obtain – in the structure of gels – compounds similar to the hydroxyapatites present naturally in bone tissue, gels after sorption were modified in: pH 7 buffer and sodium hydrogen phosphate. In order to determine the structural properties of the gels, the following methods were used: infrared spectroscopy with Fourier transformation, FTIR, X-ray diffractometry, XRD, scanning electron microscopy, SEM.
Changes in structure of dibutyrylchitin fibres in the process of chitin regeneration Summary -Dib... more Changes in structure of dibutyrylchitin fibres in the process of chitin regeneration Summary -Dibutyrylchitin (DBCH) fibres were formed from the solution of the polymer in and anhydrous ethyl alcohol. The fibres obtained were then treated with a 5 % aq. potassium hydroxide solution at temperatures ranging from 20 o C to 90 o C. The process of chitin regeneration was carried out gradually and its rate depended on the temperature. High temperature alkaline treatment causes that the transformation of DBCH fibres into fibres of regenerated chitin becomes more effective. Molecular and supermolecular structural changes of fibres were examined by wide angle X-ray diffraction (WAXS), FT-IR spectroscopy and Raman spectroscopy. The obtained diffractograms were analyzed using Hindeleh and Johnson method and the computer programme "Optifit" in which Rosenbrock method was applied. The analysis of WAXS diffraction patterns showed that the curve obtained for regenerated chitin is similar to the curve obtained for the native krill chitin. The analysis of FT-IR spectra proved that as a result of hydrolysis of DBCH fibres the transformation of DBCH into chitin took place and chemical structure of the obtained chitin was almost the same as the structure of the initial native chitin.
Progress on Chemistry and Application of Chitin and its Derivatives, Sep 30, 2017
In this study, a solution of dibutyrylchitin (DBC)/polylactide (PLA) blend micro and nanofibres w... more In this study, a solution of dibutyrylchitin (DBC)/polylactide (PLA) blend micro and nanofibres were successfully fabricated using blends of 2,2,2-trifluoroethanol (TFE) as solvents. Fibres were produced from the solutions by electrospinning. The DBC/PLA blend solutions in various ratios were studied for electrospinning into micro/nanofibres. The morphology of the micro and nanofibres was observed by scanning electron microscope (SEM). The biggest diameters of DBC/PLA fibres were obtained for the blended microfibres in ratios of 10/90 and 25/75. The smallest diameter was observed for pure polymers. The antibacterial properties were examined for materials obtained by electrospinning. In the experiments, materials with antibacterial properties were made. It is likely that the electrospun micro and nanofibres will be used in the native extracellular matrix for tissue engineering.
The article presents a new fabrication method for bioactive fibres with a microporous structure o... more The article presents a new fabrication method for bioactive fibres with a microporous structure of ethylene–vinyl alcohol copolymers (EVOH)/ethylene−propylene copolymer (EPC) blends. The experimental work carried out resulted in obtaining EVOH/EPC polymer blends fibres with the addition of glycerol and sodium stearate. Different concentrations of glycerol (38%, 32%) and sodium stearate (2%, 8%) were used to prepare the fibres. The purpose of using different concentrations of stearate and glycerol was to evaluate the effect of additives on the structure and properties of the fibres. A significant influence of the additives used on the morphological structure of the fibres was found. The resulting fibres were modified with an AgNO3 solution and reduced to silver nanoparticles (AgNPs), to give the fibres bioactive properties. The fibres obtained with the addition of 8% stearate have a more developed surface, which may influence the amount of adsorbed silver particles inside the fibre. ...
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