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1.
Int J Biol Macromol ; 266(Pt 1): 131190, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38552689

RESUMO

In this study, new, functional hydroxyapatite-lignin hybrid systems were designed and characterized. The efficacy of the mechanical method utilized to obtain these systems was confirmed by Fourier transform infrared spectroscopy. The hybrid materials were also noted for their good electrokinetic stability and thermal stability. The introduction of 2.5 to 10 wt% hydroxyapatite-lignin systems into an unplasticized PVC blend using a two-step kneading and pressing method resulted in composites with relatively homogeneous distribution, as confirmed by SEM observations. The processing properties of the filler-containing blends were investigated using plastographometric analysis and MFR tests. The introduction of a lignin-predominant hybrid system into the PVC matrix results in a significant improvement of thermal stability, softening temperature, and tensile strength, while maintaining sufficient impact strength for numerous applications. Hybrid materials containing higher amounts of added lignin are promising materials with bacteriostatic properties. This can be utilized to stabilize and prevent the deposition of microorganisms, as well as the formation of biofilms, on material surfaces, thereby limiting the spread of pathogens. New eco-composites based on PVC and a hybrid filler containing lignin show promise in producing components with surfaces resistant to bacterial colonization. Hence, these materials could be used in medical and hospital equipment.

2.
Polymers (Basel) ; 16(4)2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38399852

RESUMO

The main objective of this study was to discover new packaging materials that could integrate one of the most expected properties, such as UV protection, with a self-cleaning ability defined as photocatalytic performance. Accordingly, new hybrid additives were used to transform LDPE films into materials with complex performance properties. In this study, titanium dioxide-lignin (TL) hybrid systems with a weight ratio of inorganic to organic precursors of 5-1, 1-1, and 1-5 were prepared using a mechanical method. The obtained materials and pristine components were characterized using measurement techniques and research methods, such as Fourier-transform infrared spectroscopy (FTIR), thermal stability analysis (TGA/DTG), measurement of the electrokinetic potential as a function of pH, scanning electron microscopy (SEM), and particle size distribution measurement. It was found that hydrogen bonds were formed between the organic and inorganic components, based on which the obtained systems were classified as class I hybrid materials. In the next step, inorganic-organic hybrid systems and pristine components were used as fillers for a low-density polyethylene (LDPE) composite, 5 and 10% by weight, in order to determine their impact on parameters such as tensile elongation at break. Polymer composites containing titanium dioxide in their matrix were then subjected to a test of photocatalytic properties, based on which it was found that all materials with TiO2 in their structure exhibit photocatalytic properties, whereby the best results were obtained for samples containing the TiO2-lignin hybrid system (1-1). The mechanical tests showed that the thin sheet films had a strong anisotropy due to chill-roll extrusion, ranging from 1.98 to 3.32. UV-Vis spectroscopy revealed four times higher light absorption for composites in which lignin was present than for pure LDPE, in the 250-450 nm range. On the other hand, the temperature at 5% and 30% weight loss revealed by TGA testing increased the highest performance for LDPE/TiO2 materials (by 20.4 °C and 8.7 °C, respectively).

3.
Materials (Basel) ; 16(18)2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37763502

RESUMO

The requirements related to reducing the carbon footprint of cement production have directed the attention of researchers to the use of waste materials such as blast-furnace slag or fly ashes, either as a partial replacement for cement clinker or in the form of new alternative binders. This paper presents alkali-activated materials (AAMs) based on blast-furnace slag partially replaced with fly ash, metakaolin, or zeolite, activated with water glass or water glass with a small amount of water, and doped with zinc oxide. The mortars were tested for flow, hydration heat, mechanical strength, microstructure, and antimicrobial activity. The obtained test results indicate the benefits of adding water, affecting the fluidity and generating a less porous microstructure; however, the tested hydration heat, strength, and antibacterial properties are related to more favorable properties in AAMs produced on water glass alone.

4.
Chemosphere ; 341: 139927, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37633614

RESUMO

Recently, much attention has been focused on the application of the Ionic Liquids (ILs) with herbicidal activity in agriculture. It has been suggested that through the appropriate selection of cations and anions, one can adjust the properties of ILs, particularly the hydrophobicity, solubility, bioavailability, toxicity. In practical agricultural conditions, it will be beneficial to reduce the mobility of herbicidal anions, such as the commonly applied 2,4-dichlorophenoxyacetic acid [2,4-D] in the soil. Furthermore, microplastics are becoming increasingly prevalent in the soil, potentially stimulating herbicidal sorption. Therefore, we investigated whether cations in ILs influence the mobility of anions in OECD soil supplemented with polystyrene microplastic (PS). For this purpose, we used the 2,4-D based ILs consisting of: a hydrophilic choline cation [Chol][2,4-D] and a hydrophobic choline cation with a C12chain [C12Chol][2,4-D]. Characterization of selected micropolystyrene was carried out using the BET sorption-desorption isotherm, particle size distribution and changes in soil sorption parameters such as soil sorption capacity and cation exchange capacity. Based on the batch sorption experiment, the effect of microplastic on the sorption of individual cations and anions in soil contaminated with micropolystyrene was evaluated. The results obtained indicate that the introduction of a 1-10% (w/w) PS resulted in an 18-23% increase of the soil sorption capacity. However, the sorption of both ILs' cations increased only by 3-5%. No sorption of the [2,4-D] anion was noted. This suggests that cations and anions forming ILs, behave independently of each other in the environment. The results indicate the fact that ILs upon introduction into the environment are not a new type of emerging contaminant, but rather a typical mixture of ions. It is worth noting that when analyzing the behavior of ILs in the environment, it is necessary to follow the fate of both cations and anions.


Assuntos
Herbicidas , Líquidos Iônicos , Microplásticos , Plásticos , Líquidos Iônicos/química , Poliestirenos , Solo/química , Ânions , Herbicidas/química , Cátions/química , Colina , Ácido 2,4-Diclorofenoxiacético
5.
Molecules ; 28(16)2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37630317

RESUMO

In this research, we aimed to design an eco-efficient composite based on alkali-activated materials (AAMs) with self-cleaning properties for sustainable construction. Significant emphasis was placed on determining the role of the type of precursor, the amount of sodium silicate, and the addition of titanium dioxide on the rheological and mechanical properties of AAMs. An important aspect of the research was the modification of AAM with titanium dioxide to obtain the self-cleaning properties. Titanium dioxide, thanks to its photocatalytic properties, enables the reduction of organic pollutants and nitrogen oxides in the urban atmosphere and promotes the cleaning of material surfaces. Blast furnace slag (BFS) was used as the source material, which was then substituted in subsequent formulations with metakaolinite at 50% and fly ash and zeolite at 30%. The best-activated AAMs, in which blast furnace slag and its mixture with metakaolinite were used as precursors, achieved compressive strengths of 50 MPa. BFS mixtures with pozzolans were more difficult to polymerize, although their final strengths were still relatively high, in the range of 33-37 MPa. Adding titanium dioxide (T) improved the final strengths and slightly lowered the heat of hydration and spreading of the AAM mortars. The best self-cleaning properties were achieved with composites that comprised a mixture of blast furnace slag, fly ash, and 2% titanium dioxide.

6.
Int J Biol Macromol ; 246: 125626, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37392911

RESUMO

In this study, new TiO2-lignin hybrid systems were synthesized and characterized by various methods, including non-invasive backscattering (NIBS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), elemental analysis (EA) and zeta potential analysis (ZP). The weak hydrogen bonds between the components, as shown on FTIR spectra, proved the production of class I hybrid systems. TiO2-lignin systems were found to display good thermal stability and relatively good homogeneity. These newly designed hybrid materials were used to produce functional composites via rotational molding in a linear low-density polyethylene (LLDPE) matrix at 2.5 % and 5.0 % loading by weight of the fillers, namely, TiO2, TiO2-lignin (5:1 wt./wt.), TiO2-lignin (1:1 wt./wt.), TiO2-lignin (1:5 wt./wt.) and pristine lignin, creating rectangular specimens. The mechanical properties of the specimens were measured via compression testing and by low-energy impact damage testing (the drop test). The results showed that the system containing 5.0 % by weight of TiO2-lignin (1:1 wt./wt.) had the most positive effect on the container's compression strength, while the LLDPE filled with 5.0 % by weight of TiO2-lignin (5:1 wt./wt.) demonstrated the best impact resistance among all the tested composites.

7.
Int J Mol Sci ; 24(14)2023 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-37511517

RESUMO

Nanoparticles are extremely promising components that are used in diagnostics and medical therapies. Among them, silica nanoparticles are ultrafine materials that, due to their unique physicochemical properties, have already been used in biomedicine, for instance, in cancer therapy. The aim of this study was to investigate the cytotoxicity of three types of nanoparticles (SiO2, SiO2-SH, and SiO2-COOH) in relation to red blood cells, as well as the impact of silicon dioxide nanoparticles on biological membranes and liposome models of membranes. The results obtained prove that hemolytic toxicity depends on the concentration of nanoparticles and the incubation period. Silica nanoparticles have a marginal impact on the changes in the osmotic resistance of erythrocytes, except for SiO2-COOH, which, similarly to SiO2 and SiO2-SH, changes the shape of erythrocytes from discocytes mainly towards echinocytes. What is more, nanosilica has an impact on the change in fluidity of biological and model membranes. The research gives a new view of the practical possibilities for the use of large-grain nanoparticles in biomedicine.


Assuntos
Nanopartículas , Dióxido de Silício , Dióxido de Silício/química , Nanopartículas/química , Eritrócitos , Membrana Celular , Membranas
8.
Sci Rep ; 13(1): 10404, 2023 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-37369694

RESUMO

CuO nanoparticles (NPs) were added to cement matrices in quantities of 0.25, 0.50 and 1.00 wt% to inhibit the growth of Gram-positive (Bacillus cereus, Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa, Escherichia coli) bacteria. It was shown that CuO NPs, in all tested concentrations, improved the antibacterial properties of the cement matrix. Nevertheless, the best mechanical, structural and durability properties were obtained for cement composites doped with CuO NPs at 0.25 wt%. Larger amounts of NPs caused a decrease in all parameters relative to the reference mortar, which may be the result of a slight change in the porosity of the composite microstructure. For 0.50 wt% CuO NPs, a slight increase in the volume of micropores in the cement matrix was observed, and an increased number of larger pores was confirmed by non-invasive computed tomography (CT). The reduction in the mechanical parameters of composites with 0.50 and 1.00 wt% CuO NPs may also be due to the slower hydration of the cement binder, as confirmed by changes in the heat of hydration for these configurations, or agglomeration of NPs, especially for the 1.00 wt% concentration, which was manifested in a decrease in the plasticity of the mortars.


Assuntos
Antibacterianos , Nanopartículas , Antibacterianos/farmacologia , Antibacterianos/química , Cobre/farmacologia , Cobre/química , Nanopartículas/química , Bactérias
9.
Int J Biol Macromol ; 235: 123876, 2023 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-36870630

RESUMO

In this publication, the functional TiO2-lignin hybrid materials were designed and characterized. Based on elemental analysis and Fourier transform infrared spectroscopy, the efficiency of the mechanical method used to obtain systems was confirmed. Hybrid materials were also characterized by good electrokinetic stability, in particular in the inert and alkaline environments. The addition of TiO2 improves thermal stability in the entire analyzed range of temperatures. Similarly, as the content of inorganic component increases, the homogeneity of the system and the occurrence of smaller nanometric particles increase. In addition, a novel synthesis method of cross-linked polymer composites based on a commercial epoxy resin and an amine cross-linker was described as a part of the article, where additionally newly designed hybrids were also used. Subsequently, the obtained composites were subjected to simulated tests of accelerated UV-aging, and then their properties were studied, including changes in wettability (using water, ethylene glycol, and diiodomethane as measurement liquids) and surface free energy by the Owens-Wendt-Eabel-Kealble method. Changes in the chemical structure of the composites were monitored by FTIR spectroscopy due to aging. Microscopic studies of surfaces were also carried out as well as measurements in the field of changes in color parameters in the CIE-Lab system.


Assuntos
Resinas Epóxi , Lignina , Lignina/química , Resinas Epóxi/química , Titânio , Temperatura
10.
Materials (Basel) ; 15(22)2022 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-36431589

RESUMO

In this article, halloysite-lignin hybrid materials (HL) were designed and obtained. The weak hydrogen bonds found between the components were determined based on Fourier transform infrared spectroscopy (FTIR), proving the achievement of class I hybrid systems. The HL systems were characterized by very good thermal stability and relatively good homogeneity, which increased as the proportion of the inorganic part increased. This was confirmed by analyzing scanning electron microscope (SEM) images and assessing particle size distributions and polydispersity indexes. Processing rigid poly(vinyl chloride) (PVC) with HL systems with a content of up to 10 wt% in a Brabender torque rheometer allowed us to obtain composites with a relatively homogeneous structure confirmed by SEM observations; simultaneously, a reduction in the fusion time was noted. An improvement in PVC thermal stability of approximately 40 °C for composites with HL with a ratio of 1:5 wt/wt was noted. Regardless of the concentration of the HL system, PVC composites exhibited inconsiderably higher Young's modulus, but the incorporation of 2.5 wt% of fillers increased Charpy impact strength by 5-8 kJ/m2 and doubled elongation at break. This study demonstrated that favorable mechanical properties of PVC composites can be achieved, especially with an HL system with a ratio of 5:1 wt/wt.

11.
Front Chem ; 10: 946665, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35873052

RESUMO

In this study, lignin-based spherical particles (Lig-IL) with the use of 1-(propoxymethyl)-1H-imidazolium hydrogen sulfate were prepared in different biopolymer and ionic liquid (IL) weight ratios. The application of IL during the preparation of spherical particles is an innovative method, which may be beneficial for further applications. The particles were obtained with the use of the soft-templating method and their chemical, structural and morphological characterization was performed. The spherical shape of products and their size (91-615 nm) was confirmed with the use of scanning electron microscopy (SEM) images and the particle size distribution results. The attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra were analyzed to identify functional groups of all precursors and produced material and it was confirmed, that all materials exhibit characteristic hydroxyl and carboxylic groups, but the presence of carbonyl group was detected. Moreover, the zeta potential analysis was performed to evaluate the electrokinetic behavior of obtained materials. It was confirmed, that all materials are colloidally stable in pH above 4. Produced lignin-based spherical particles were used for evaluation of their antibacterial properties. Particles were tested against Staphylococcus aureus (S. aureus), a gram-positive bacterium, and Escherichia coli (E. coli), a gram-negative one. It was observed, that only the material with the highest addition of IL showed the antibacterial properties against both strains. A reduction of 50% in the number of microorganisms was observed for particles with the addition of hydrogen sulfate ionic liquid in a 1:1 ratio after 1 h. However, all prepared materials exhibited the antibacterial activity against a gram-positive bacterium.

12.
Materials (Basel) ; 15(13)2022 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-35806615

RESUMO

The influence of filler particle size on selected physicochemical and functional properties of polymer composites was analyzed. The following test was carried out for the system: the bisphenol A glycerolate (1 glycerol/phenol) di-methacrylate (BPA.DM) was subjected to UV-polymerization in bulk with N-vinyl-2-pyrrolidone (NVP) as a polymer matrix and talc with particle sizes ranging from ≤8 to 710 µm as a non-toxic and cheap mineral filler. An effective method of preparing cross-linked polymeric composites with talc was developed. The obtained samples were subjected to structural analysis and the thermal, mechanical and flammability properties were assessed. It has been empirically confirmed that the talc particles are incorporated into the composite structure. However, with increasing particle size, the composite heterogeneity increases. In the case of the developed method of sample production, homogeneous systems were obtained for particles in the ≤8-250 µm range. The surface roughness of the samples correlates directly with the size of talc particles. The value of Young's modulus during the axial stretching of samples decreases with the increasing size of talc particles. For the composites containing ≤15 and ≤35 µm talc particles, the highest values were obtained under bending conditions. There was no equivocal effect of particle size on the composites' swelling in water. The addition of talc reduces the flame height and intensity slightly. The biggest difference was obtained for the composites containing relatively large talc particles. It was proved that the selected properties of polymer composites can be controlled depending on the size of the talc particles.

13.
Polymers (Basel) ; 14(7)2022 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-35406329

RESUMO

This paper presents an analysis of research results for silica aerogel cement composites over the past twenty years. Recently, two trends in the development of these composites have been noted, towards structural applications and towards ultralight composites for coatings and renders. Ongoing research shows that important aspects of cementitious composites with good mechanical performance are the proper selection of aggregates and improved adhesion at the silica aerogel-cement binder interface, which will guarantee high compressive strength with the lowest possible thermal conductivity. The best physicomechanical performance of aerogel cement composites with low thermal conductivity below 0.03 W/(m·K) was obtained when cenospheres and aerogel were used in a weight percentage of 5%. In turn, the prerequisites for using aerogel cement composites as coatings for energy-efficient building façades are the use of large amounts of silica aerogel as a substitute for lightweight aggregates or the selection of an optimal composition of lightweight aggregates and aerogel, ensuring the lowest possible thermal conductivity coefficient. Other important standpoints are water transport and moisture protection of the silica aerogel-based coatings. Therefore, in recent years, more and more elements of the hygrothermal performance, porosity and durability of silica aerogel cement composites have been developed. The article also points out the weaknesses of the application of silica aerogel in the cement matrix, the most important of which are the lack of adhesion at the boundary of the aerogel-cement binder, the increased porosity of the composite, the high water absorption capacity and the significant decrease in compressive strength with large volumes of silica aerogel. Solving these issues will certainly contribute to the wider applicability of these materials in the construction industry.

14.
Materials (Basel) ; 15(2)2022 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-35057378

RESUMO

In recent years, increasing attention has been paid to the durability of building materials, including those based on cementitious binders. Important aspects of durability include the increase of the strength of the cement matrix and enhancement of material resistance to external factors. The use of nanoadditives may be a way to meet these expectations. In the present study, zinc, titanium and copper oxides, used in single and binary systems (to better the effect of their performance), were applied as additives in cement mortars. In the first part of this work, an extensive physicochemical analysis of oxides was carried out, and in the second, their application ranges in cement mortars were determined. The subsequent analyses were employed in determining the physicochemical properties of pristine oxides: Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray fluorescence (EDXRF), scanning electron microscopy (SEM), measurement of the particle size distribution, as well as zeta potential measurement depending on the pH values. Influence on selected physicomechanical parameters of the cement matrix and resistance to the action of selected Gram-positive and Gram-negative bacteria and fungi were also examined. Our work indicated that all nanoadditives worsened the mechanical parameters of mortars during the first 3 days of hardening, while after 28 days, an improvement was achieved for zinc and titanium(IV) oxides. Binary systems and copper(II) oxide deteriorated in strength parameters throughout the test period. In contrast, copper(II) oxide showed the best antibacterial activity among all the tested oxide systems. Based on the inhibitory effect of the studied compounds, the following order of microbial susceptibility to inhibition of growth on cement mortars was established (from the most susceptible, to the most resistant): E. coli < S. aureus < C. albicans < B. cereus = P. aeruginosa < P. putida.

15.
Polymers (Basel) ; 13(23)2021 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-34883642

RESUMO

Water pollution by toxic substances, such as azo dyes, is a serious environmental problem that needs to be addressed. This study presents the synthesis and characterization of new polymeric sorbents, based on the epoxy resin Epidian® 5 (Ep5), as a potential adsorbent for the removal of the toxic azo dye C.I. Acid Violet 1 (AV1). Triethylenetetramine (TETA) was applied as a cross-linking agent in the amounts of 1 g (6.67 wt %), 1.5 g (10 wt %), and 2 g (13.33 wt %). The use of a compound with amino groups allows for the simultaneous functionalization of the obtained material. The reaction was carried out in an environment of ethylene glycol, with the addition of a porophore solvent (toluene) and bis(2-ethylhexyl)sulfosuccinate sodium salt (S). The attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) revealed the existence of a strong band in the 828-826 cm-1 range corresponding to the second-order amine group, which indicates their incorporation into the epoxy structure. The glass transition and decomposition temperatures of the resins decreased with the increasing amounts of amine in the material. The thermogravimetry (TGA) analysis demonstrated that all products are thermally stable up to 340 °C. The surface morphology and microstructural properties of the obtained sorbents were determined using scanning electron microscopy (SEM) images and showed an irregular star shape, with dimensions ranging from 400 to 1000 µm. The adsorption capacities of Ep5-TETA1, Ep5-TETA1.5, Ep5-TETA2 and Ep5-TETA1.5 + S for AV1 evaluated during batch experiments were found to be 2.92, 3.76, 7.90 and 3.30 mg/g, respectively.

16.
Int J Biol Macromol ; 190: 624-635, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517024

RESUMO

Within this study, the ZrO2/lignin and ZrO2-SiO2/lignin hybrid materials were obtained for the first time. The mechanical grinding method was used for this purpose. In order to determine the properties of obtained lignin-based hybrids and the components used to produce them, as well as to evaluate the efficiency of their preparation, the authors used such research techniques as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), elemental analysis, porous structure analysis and thermal stability assessment (TGA/DTG). The next step involved using the components and produced hybrid materials as polymer fillers for poly(methyl methacrylate) (PMMA). The obtained lignin-based hybrid biocomposites have then been thoroughly characterized using gel permeation chromatography (GPC), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and hardness testing. All the conducted tests confirm the possibility of using the obtained bio-based products in practice, within the widely understood construction industry, for producing durable building facades or noise barriers, among others.


Assuntos
Materiais Biocompatíveis/química , Lignina/química , Polímeros/química , Varredura Diferencial de Calorimetria , Fenômenos Químicos , Elementos Químicos , Dureza , Lignina/ultraestrutura , Tamanho da Partícula , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria
17.
Int J Biol Macromol ; 186: 181-193, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34246669

RESUMO

A new type of functional lignin-based spherical particles (L-CTAB) prepared with the use of hexadecyltrimethylammonium bromide (CTAB) was applied as an effective biosorbent for removing vanadium(V) ions. The porous structure, characteristic functional groups, electrokinetic stability, morphology and size of the L-CTAB particles were examined. The conditions of removal were also investigated, including pH (2-12), sorbent mass (0.1-0.5 g), concentration (10-100 mg/dm3), phase contact time (1-240 min) and temperature (293-333 K). At pH 5.0 the maximum sorption percentage (%S) of V(V) was 45%, while at pH 2.0 it was 32%. The maximum sorption capacity of V(V) for L-CTAB was found to be 10.79 mg/g. The kinetic data indicate that the sorption followed the pseudo-second-order and film diffusion models. Sorption equilibrium for V(V) ions removal by L-CTAB was reached after 60 min at the initial concentrations 10 and 50 mg/dm3. It has been shown that the adsorption of V(V) ions on the surface of L-CTAB is a heterogeneous, endothermic and spontaneous reaction, as evidenced by the calculated values of thermodynamic parameters - free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) - for the tested systems at different temperatures. HCl solutions, used as an L-CTAB regeneration agent, quantitatively eluted V(V) ions.


Assuntos
Lignina/química , Vanádio/isolamento & purificação , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água , Adsorção , Cetrimônio/química , Cinética , Tamanho da Partícula , Porosidade , Propriedades de Superfície , Tensoativos/química , Temperatura
18.
Int J Biol Macromol ; 187: 624-650, 2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34302869

RESUMO

The construction industry in the 21st century faces numerous global challenges associated with growing concerns for the environment. Therefore, this review focuses on the role of lignin and its derivatives in sustainable construction. Lignin's properties are defined in terms of their structure/property relationships and how structural differences arising from lignin extraction methods influence its application within the construction sector. Lignin and lignin composites allow the partial replacement of petroleum products, making the final materials and the entire construction sector more sustainable. The latest technological developments associated with cement composites, rigid polyurethane foams, paints and coatings, phenolic or epoxy resins, and bitumen replacements are discussed in terms of key engineering parameters. The application of life cycle assessment in construction, which is important from the point of view of estimating the environmental impact of various solutions and materials, is also discussed.


Assuntos
Mudança Climática , Indústria da Construção , Materiais de Construção , Lignina/química , Desenvolvimento Sustentável , Indústria da Construção/tendências , Materiais de Construção/efeitos adversos , Resinas Epóxi/efeitos adversos , Resinas Epóxi/química , Formaldeído/efeitos adversos , Formaldeído/química , Humanos , Hidrocarbonetos/efeitos adversos , Hidrocarbonetos/química , Pintura/efeitos adversos , Fenóis/efeitos adversos , Fenóis/química , Polímeros/efeitos adversos , Polímeros/química , Poliuretanos/efeitos adversos , Poliuretanos/química , Medição de Risco , Desenvolvimento Sustentável/tendências
19.
Materials (Basel) ; 14(9)2021 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-33921994

RESUMO

In this study, MgO-lignin (MgO-L) dual phase fillers with varying amounts of lignin as well as pristine lignin and magnesium oxide were used as effective bio-fillers to increase the ultraviolet light protection and enhance the barrier performance of low density polyethylene (LDPE) thin sheet films. Differential scanning calorimetry (DSC) was used to check the crystalline structure of the studied samples, and scanning electron microscopy (SEM) was applied to determine morphological characteristics. The results of optical spectrometry in the range of UV light indicated that LDPE/MgO-L (1:5 wt/wt) composition exhibited the best protection factor, whereas LDPE did not absorb ultraviolet waves. Moreover, the addition of hybrid filler decreased the oxygen permeability factor and water vapor transmission compared with neat LDPE and its composites with pristine additives, such as lignin and magnesium oxide. The strong influence of the microstructure on thin sheet films was observed in the DSC results, as double melting peaks were detected only for LDPE compounded with inorganic-organic bio-fillers: LDPE/MgO-L.

20.
Polymers (Basel) ; 13(6)2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33809286

RESUMO

This study presents the preparation and the thermo-mechanical characteristics of polymeric blends based on di(meth)acrylates monomers. Bisphenol A glycerolate diacrylate (BPA.GDA) or ethylene glycol dimethacrylate (EGDMA) were used as crosslinking monomers. Methyl methacrylate (MMA) was used as an active solvent in both copolymerization approaches. Commercial polycarbonate (PC) was used as a modifying soluble additive. The preparation of blends and method of polymerization by using UV initiator (Irqacure® 651) was proposed. Two parallel sets of MMA-based materials were obtained. The first included more harmless linear hydrocarbons (EGDMA + MMA), whereas the second included the usually used aromatic copolymers (BPA.GDA + MMA). The influence of different amounts of PC on the physicochemical properties was discussed in detail. Chemical structures of the copolymers were confirmed by attenuated total reflection-Fourier transform infrared (ATR/FT-IR) spectroscopy. Thermo-mechanical properties of the synthesized materials were investigated by means of differential scanning calorimetry (DSC), thermogravimetric (TG/DTG) analyses, and dynamic mechanical analysis (DMA). The hardness of the obtained materials was also tested. In order to evaluate the surface of the materials, their images were obtained with the use of atomic force microscopy (AFM).

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