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1.
Molecules ; 28(16)2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37630341

RESUMO

Defining the kidney stone composition is important for determining a treatment plan, understanding etiology and preventing recurrence of nephrolithiasis, which is considered as a common, civilization disease and a serious worldwide medical problem. The aim of this study was to investigate the morphology and chemical composition of multicomponent kidney stones. The identification methods such as infrared spectroscopy (FTIR), X-ray diffraction (XRD), and electron microscopy with the EDX detector were presented. The studies by the X-ray photoelectron spectroscopy (XPS) were also carried out for better understanding of their chemical structure. The chemical mapping by the FTIR microscopy was performed to show the distribution of individual chemical compounds that constitute the building blocks of kidney stones. The use of modern research methods with a particular emphasis on the spectroscopic methods allowed for a thorough examination of the subject of nephrolithiasis.


Assuntos
Cálculos Renais , Humanos , Rim , Projetos de Pesquisa , Microscopia , Espectroscopia Fotoeletrônica
2.
Chemphyschem ; 24(22): e202300490, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37563995

RESUMO

Polymer science exploited metal organic frameworks (MOFs) for various purposes, which is due to the fact that these materials are ideal platforms for identifying design features for advanced functional materials. The mechanism of polymerization using MOFs, is still largely unexplored and the detailed characterization of both materials in essential to understand the important interactions between the components. In this work modern advanced research methods were used to investigate the properties of MOF-containing hybrid polymeric microspheres. Hydrothermal conversion of CFA-derived iron particles was used to obtain MOF nanostructures, which were then introduced to the structure of hybrid polymer microspheres based on ethylene glycol dimethylacrylate (EGDMA) and triethoxyvinylsilane (TEVS). Chemical structures were confirmed by ATR-FTIR method. To provide information about the elemental composition of the tested materials and for the determination of chemical bonds present in the tested samples XPS method was applied. Morphology was studied using SEM microscopy, whereas porosity was investigated using ASAP technique. Swellability coefficients were determined using typical organic solvents and distilled water. Moreover, the ecological aspect concerning the use of fly ashes deserves to be emphasized.

3.
Materials (Basel) ; 14(11)2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34071511

RESUMO

The aim of the presented research was to investigate the mechanism of sorption of Cu(II) ions on the commercially available Purolite S 940 and Purolite S 950 chelating ion exchangers with the aminophosphonic functional groups. In order to understand better the sorption mechanism, the beads were cut with an ultramicrotome before and after the Cu(II) ion sorption process. The cut beads were examined by scanning electron microscopy (SEM) with an EDX detector. The performed linear profiles of the elemental composition allowed us to examine the depth with which the sorbed metal penetrates into. For further investigations concerning the mechanism of the sorption process, the Fourier transform infrared spectroscopy (FTIR) analysis using the attenuated total reflectance (ATR) technique and the X-ray photoelectron spectroscopy (XPS) methods have been used. The comparison of FTIR and XPS spectra before and after the sorption of Cu(II) ions showed that free electron pairs from nitrogen and oxygen in the aminophosphonic functional groups participate in the process of copper ion sorption. In addition, the microscopic studies suggested that the process of ion exchange between Na(I) ions and sorbed Cu(II) ions takes place on the Purolite S 940 and Purolite S 950. This study concerning the in-depth understanding the of Cu(II) sorption mechanism, using modern analytical tools and research methods could be very useful for its further modifications leading to the improvement of the process efficiency.

4.
Int J Biol Macromol ; 178: 344-353, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33652053

RESUMO

This study concerns the synthesis of biocomposites with kraft lignin, investigation of their physicochemical properties, and tests of their resistance to environmental factors such as UV irradiation and water. The biocomposites were synthesized using bisphenol A glycerolate (1 glycerol/phenol) diacrylate (BPA.DA) as a main monomer, ethylene glycol dimethacrylate (EGDMA) as a reactive diluent, and kraft lignin (L) as an environmentally friendly filler, in a UV curing process. Morphological analysis of the resulting materials was carried out using scanning electron microscopy and confocal microscopy. Thermal properties were investigated using thermogravimetric analysis. Tensile and flexural tests were performed for all obtained materials. Additionally, the wettability and swelling of the obtained composite samples were analyzed. The changes observed in the structure and properties of the polymers as a result of aging were investigated by means of ATR-FTIR analysis, optical profilometry and hardness tests. The results obtained regarding the effect of lignin addition on the properties of composite materials, with particular emphasis on their resistance to environmental factors, may be of crucial importance for their further applications, inter alia as UV-curable coating materials.


Assuntos
Lignina/química , Teste de Materiais , Metacrilatos/química
5.
Molecules ; 25(24)2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33334041

RESUMO

In this paper flammability tests and detailed investigations of lignin-containing polymer composites' properties are presented. Composites were obtained using bisphenol A glycerolate (1 glycerol/phenol) diacrylate (BPA.GDA), ethylene glycol dimethacrylate (EGDMA), and kraft lignin (lignin alkali, L) during UV curing. In order to evaluate the influence of lignin modification and the addition of flame retardant compounds on the thermal resistance of the obtained biocomposites, flammability tests have been conducted. After the modification with phosphoric acid (V) lignin, as well as diethyl vinylphosphonate, were used as flame retardant additives. The changes in the chemical structures (ATR-FTIR), as well as the influence of the different additives on the hardness, thermal (TG) and mechanical properties were discussed in detail. The samples after the flammability test were also studied to assess their thermal destruction.


Assuntos
Acrilatos/química , Retardadores de Chama/análise , Lignina/química , Dureza
6.
Polymers (Basel) ; 12(5)2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32438552

RESUMO

The preparation and the thermal and mechanical characteristics of lignin-containing polymer biocomposites were studied. Bisphenol A glycerolate (1 glycerol/phenol) diacrylate (BPA.GDA) was used as the main monomer, and butyl acrylate (BA), 2-ethylhexyl acrylate (EHA) or styrene (St) was used as the reactive diluent. Unmodified lignin (L) or lignin modified with methacryloyl chloride (L-M) was applied as an ecofriendly component. The influences of the lignin, its modification, and of the type of reactive diluent on the properties of the composites were investigated. In the biocomposites with unmodified lignin, the lignin mainly acted as a filler, and it seemed that interactions occurred between the hydroxyl groups of the lignin and the carbonyl groups of the acrylates. When methacrylated lignin was applied, it seemed to take part in the creation of a polymer network. When styrene was added as a reactive diluent, the biocomposites had a more homogeneous structure, and their thermal resistance was higher than those with acrylate monomers. The use of lignin and its methacrylic derivative as a component in polymer composites promotes sustainability in the plastics industry and can have a positive influence on environmental problems related to waste generation.

7.
Materials (Basel) ; 13(7)2020 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-32283784

RESUMO

This paper deals with the synthesis and studies of new polymer microspheres properties based on ethylene glycol dimethylacrylate (EGDMA), styrene (St), and various quantities of commercial kraft lignin (L). In the first stage of the investigations, the conditions of the synthesis process were optimized by selecting a proper amount of poly (vinyl alcohol), which was a suspension stabilizer. Next, based on EGDMA + St + L, new polymers were synthesized by the suspension polymerization method. The chemical structure of the materials was confirmed by means of the Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) analysis. The evaluation of the synthesized materials includes susceptibility to swelling in solvents of different character (polar and nonpolar), porous structure of microspheres, and their thermal resistance. Morphology has been specified by the scanning electron microscope and automated particle size, as well as shape analyzer. The obtained pictures confirmed the spherical shape of the materials. The microspheres porosity was characterized using the low-temperature nitrogen adsorption. To increase the porosity (partially blocked by the large lignin molecule), the microspheres (EGDMA + St + 4L copolymer) were impregnated with the aqueous solution of the activating substance (sulphuric acid, nitric acid, phosphorous acid, and silver nitrate) and then carbonized at 400 °C. After the carbonization process, the increase in the specific surface area was observed. The microspheres were porous with a specific surface area up to 300 m2/g. The materials had a desirable feature for their potential use in chromatography, which was confirmed by the results of GC analysis with the acetylsalicylic acid. These materials are an interesting alternative in the field of more environmentally friendly, ecological, and biodegradable polymeric sorbents in comparison to the commonly applied styrene-divinylbenzene (St-DVB) copolymers.

8.
Materials (Basel) ; 13(1)2019 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-31877709

RESUMO

The paper investigates the properties of unsaturated polyester resins and microcrystalline cellulose (MCC) composites. The influence of MCC modification on mechanical, thermomechanical, and thermal properties of obtained materials was discussed. In order to reduce the hydrophilic character of the MCC surface, it was subjected to esterification with the methacrylic anhydride. This resulted in hydroxyl groups blocking and, additionally, the introduction of unsaturated bonds into its structure, which could participate in copolymerization with the curing resin. Composites of varying amounts of cellulose as a filler were obtained from modified MCC and unmodified (comparative) MCC. The modification of MCC resulted in obtaining composites characterized by greater flexural strength and strain at break compared with the analogous composites based on the unmodified MCC.

9.
Materials (Basel) ; 12(18)2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31487838

RESUMO

This work investigates the impact of lignin origin and structural characteristics, such as molecular weight and functionality, on the properties of corresponding porous biopolymeric microspheres obtained through suspension-emulsion polymerization of lignin with styrene (St) and/or divinylbenzene (DVB). Two types of kraft lignin, which are softwood (Picea abies L.) and hardwood (Eucalyptus grandis), fractionated by common industrial solvents, and related methacrylates, were used in the synthesis. The presence of the appropriate functional groups in the lignins and in the corresponding microspheres were investigated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR), while the thermal properties were studied by differential scanning calorimetry (DSC). The texture of the microspheres was characterized using low-temperature nitrogen adsorption. The swelling studies were performed in typical organic solvents and distilled water. The shapes of the microspheres were confirmed with an optical microscope. The introduction of lignin into a St and/or DVB polymeric system made it possible to obtain highly porous functionalized microspheres that increase their sorption potential. Lignin methacrylates created a polymer network with St and DVB, whereas the unmodified lignin acted mainly as an eco-friendly filler in the pores of St-DVB or DVB microspheres. The incorporation of biopolymer into the microspheres could be a promising alternative to a modification of synthetic materials and a better utilization of lignin.

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