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1.
J Fluoresc ; 28(4): 913-931, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29959579

RESUMO

A novel series of pyrazoline derivatives were synthesized and their spectral properties were characterized via FT-IR, 1H, and 13C NMR. The electronic transitions and fluorescence properties were tracked via UV-Vis and emission spectrometry. The density functional theory (DFT) calculations have been also computed to get spot onto the geometry, electronic transitions and spectroscopic properties theoretically that has been compared with the encountered experimental ones. Moreover, the dipole moment, optimized energy, HOMO - LUMO energies and band gaps were calculated for novel candidates pyrazoline derivatives with highly fluorescence quantum yield.

2.
Sci Rep ; 14(1): 15236, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38956097

RESUMO

This work deals with promoting the efficiency of removing the cationic and ionic dyes by new aerogel-carbon nanostructures. For cleaner production the rice straw-pulping black liquors, which regards serious environmental risk during routine disposing, is used in preparing the aerogel precursors. These aerogels (AGBs) depend on using pulping black liquor in hybrid with resorcinol and the less carcinogenic formaldehyde butyraldehyde. Black liquors from five pulping processes are used, Elemental, thermogravimetric (TGA and DTG), and FTIR-ATR analyses are used to characterize the carbon precursors. While their adsorption behavior toward cationic and anionic dyes are accessed via iodine-value, adsorption capacity and kinetic models, textural characterization, and SEM. The TGA measurements reveal that AGBs from BLs of neutral sulfite and soda-borohydride pulping reagents have higher activation and degradation energies than other aerogels. In terms of cationic and anionic dyes adsorption as well as textural characterization, the AGB-CNSs surpass that made from BLs. The discarded KOH/NH4OH black liquor is used to synthesize the best aerogel precursor for producing cationic methylene blue dye (MB) adsorbent, where it provides an adsorption capacity 242.1 mg/g. The maximum anionic brilliant blue dye (BB) adsorption capacity, 162.6 mg/g, is noticed by Kraft BL-aerogel-CNSs. These finding data overcome the literature carbon adsorbents based on lignin precursors. All examined CNSs toward MB dye follow the Langmuir adsorption equilibrium; while primarily the Freundlich model for BB dye. The pseudo-second-order kinetic model well fits the adsorption kinetics of investigated AGB-CNSs. The textural characterization and SEM revealed a mixture of mesoporous and micro porous features in the CNSs.

3.
Int J Biol Macromol ; 265(Pt 2): 131098, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38521314

RESUMO

This work deals with assessing the performance of lignin nanoparticles (LNPs) in solving the problem of using salicylic acid as an agrochemical compound, via controlling its release. LNPs, obtained from black liquor, have been used to develop new delivery systems. Gels from chelating of LNPs with chitosan or chitosan nanoparticles (Cs-NPs) in presence or absence of cationic starch are investigated to achieve this essential aim. The nanoparticles are examined by TEM, ATR-FTIR, and XRD techniques. Based on measurements of swelling, encapsulation, release profile, release kinetic modeling of salicylic acid (SA), infrared spectroscopy, thermo-gravimetric analysis and scanning electron microscope the behavior of the investigated nanocomposite gels is assessed. The results show that the SA release profile of Cs-NPs and its nanocomposite with LNPs in phosphate-buffered saline (PBS) (7.4) (51.5-69.4 %) is higher than that of the mixture of water and ethanol (34.9-50.4 %). The release profile in PBS (7.4) demonstrates a trend of prolonged SA release over a 48-hour period. Best control of the SA-release can be achieved by CsNPs-LNPs nanocomposite. Comparing the results with previous literature demonstrates the promising characteristics of these examined gel nanocomposites. The release of SA from nanocomposites is regulated by a diffusion mechanism and follows the Ritger-Peppas and Higuchi models for kinetic release.


Assuntos
Quitosana , Nanopartículas , Ácido Salicílico , Quitosana/química , Lignina , Nanopartículas/química , Géis
4.
Int J Biol Macromol ; 256(Pt 1): 128205, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37979749

RESUMO

This work deals with avoiding the pollution risks from paper pulping liquors and rubber wastes that result from routine disposal tools; moreover, finding an approach to minimize the drawback of incorporating the rubber waste in weakening the strength of building materials. In this respect, pulping black liquors (BLs) is assessed as a treating agent for rubber waste and substituting the water in cement mortar formulation. The assessment was achieved by testing the mechanical properties, water resistance (reduction in water absorption and dimensional change against water), and morphology. The results showed that all BLs from different pulping agents, used in mixtures with water, provided improvements in both strength and water resistance properties. Kraft black liquor is most effective in providing improvements in compressive strength and flexural strength, as well as resistance to water absorption and change in dimension after exposure to water for 24 h, where the improvements were 688.2 %, 494.3 %, 27 %, and 65.3 %, respectively. It is interesting to note that this investigated route provided improvements in the impact resistance property of mortar. This last property is essential for minimizing accidents on the highway.


Assuntos
Poluição Ambiental , Borracha , Materiais de Construção , Força Compressiva , Água
5.
Sci Rep ; 13(1): 13923, 2023 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-37626072

RESUMO

Upscaling the utilization of polymer wastes together with the valorization of undesirable waste rice straw (RS) will minimize the environmental impact of waste disposal by traditional tools. This present work assesses the utilization of polyethylene terephthalate wastes in enhancing the production of polyester-(high density polyethylene) HDPE from Rice straw polyol composites. In this respect, the polyester from rice straw polyol in hybrid with glycolysis polyethylene terephthalate wastes (Gly-WPET) was assessed in comparison with that resulted from RS-polyol, using FTIR, non-isothermal analysis, and mechanical tests. The data showed the positive role of Gly-WPET in hybrid with RS-polyol in production polyester with high thermal stability and mechanical properties. It provided an increase in activation energy of degradation, elongation, Young's Modulus, and modulus of toughness from 184.5 to 1201 kJ/mole, from 4.7 to 9.8%, from 47.5 to 66.5 MPa, and from ~ 4.0 to 23 J/m3, respectively. This behavior was reflected in the properties of HDPE-polyester polyol (PEPO) composites, especially in improving elongation (from 55.4 to 72%). These promising data persuade us to recommend the influential role of Gly-WPET in using PEPO from liquefied RS as a plasticizer.

6.
Sci Rep ; 13(1): 20072, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37973917

RESUMO

This work deals with providing a green pulping process of rice straw with zero waste discharged, via valorization of its by-product as a promising precursor for production of carbon nanostructures. The carbon nanostructures (BL-CNSs) from rice straw pulping liquors (BLs) are prepared in one step with phosphoric acid activation. The carbon nanostructures (BL-CNSs) from rice straw pulping liquors (BLs) are prepared in one step with phosphoric acid activation. The optimal pulping approach for achieving effective adsorbent (BL-CNSs) of cationic and anionic dyes is recommended from using different BLs precursors resulting from different reagents (alkaline, neutral, and acidic reagents). The carbon precursors are characterized by elemental, thermal (TGA and DTG) and ATR FTIR analyses. While the impact of pulping route on performance of CNSs is evaluated by their adsorption of iodine, cationic dye and anionic dye, as well as ATR-FTIR, textural characterization, and SEM. The data of elemental analysis displayed a high Carbon content ranges from 57.85 to 66.69% suitable for CNSs preparation, while the TGA showed that Sulphur-containing BLs (Kraft, neutral sulfite and acidic sulfite) have higher degradation temperature and activation energies as compared with other BLs. The optimum BL-CNSs adsorbent is prepared from the disposed neutral sulfite black liquor, with the following characteristics: cationic dye adsorption capacity 163.9 mg/g, iodine value 336.9 mg/g and SBET 310.6 m2/g. While the Kraft-CNSs provided highest anionic adsorption (70.52 mg/g). The studies of equilibrium and kinetic adsorption of dyes showed that the adsorption equilibrium of all investigated BL-CNSs toward MB follow the Langmuir and mainly Freundlich models for BB adoption. Their adsorption kinetics are a good fit with the pseudo-second-order model. The textural characterization and SEM revealed the CNSs exhibit a mixture of mesoporous and microporous structure.

7.
Int J Biol Macromol ; 165(Pt A): 1496-1506, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33058976

RESUMO

This work was done to optimize the drug delivery system based on N-trimethyl chitosan (TMC) and carboxylate-containing cellulose derivatives, as well as assessment the effective role of organic and inorganic cross-linkers for controlling release of ciprofloxacin (CPX) drug. Organic crosslinking of oxidized cellulose nanoparticle or CMC with TMC for preparing the hydrogel and their CPX drug loading were characterized by FTIR, swelling behaviour, DSC and SEM. Parallel tests were carried out on using Cu (II) ions as inorganic cross-linker. The FTIR and DSC data confirmed the formation of crosslinked delivery systems incorporated with CPX drug and candidate the TMC-CMC as the most stable delivery system. The SEM micrographs evidence the compatibility of cross-linked delivery systems with the incorporated of CPX drug through the hydrogel matrix. In vitro drug release study showed the effectiveness of organic crosslinking of TMC with CMC and OC to control the release of CPX than TMC, individually. Sustained and controlled drug releases were observed for organic crosslinked CMC (TMC-CMC) with maximum release (~75%) exceeded the TMC-OC and inorganic crosslinked CMC (Cu (II)-CMC). The release kinetics of all examined hydrogels followed Ritger-Peppas and Higuchi models, that indicating Fickian and the release of CPX was primarily controlled by diffusion process. The cell viability of human normal fibroplast cell line (BJ1) was positively correlated with the type of cellulose derivative-hydrogels and crosslinker. The TMC-CMC was recommended as promising safety and control drug release hydrogel.


Assuntos
Celulose/química , Quitosana/química , Sistemas de Liberação de Medicamentos , Nanopartículas/química , Celulose/farmacologia , Quitosana/farmacologia , Ciprofloxacina/química , Ciprofloxacina/farmacologia , Preparações de Ação Retardada , Liberação Controlada de Fármacos/efeitos dos fármacos , Humanos , Hidrogéis/química , Hidrogéis/farmacologia
8.
R Soc Open Sci ; 7(10): 200928, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33204462

RESUMO

This overall process deals with evaluating the performance of silver nanoparticles, synthesized from sodium caseinate (SC) as green biological active agent, in comparison with widely produced from carboxymethyl cellulose, other carbohydrates (oxidized nanocellulose fibres (OC) and starch (St)). The TGA, FTIR and TEM, as well as its antimicrobial activities toward pathogenic Gram-positive and Gram-negative bacteria in addition to the yeast strain Candida albicans NRRL Y-477 were examined. In addition, with regard to their anti-tumour activity, the evaluation was studied via many cancer cell lines against RPE1 (normal retina cell line). The results revealed that the SC-Ag(I) and CMC-Ag(I) complexes were formed in six- and five-membered chelate rings, respectively, as nanoparticles, while linear chelation structure was formed in case of OC-Ag(I) and St-Ag(I) complexes. The complexation of SC with Ag(I) ions was recommended as promising stable and antimicrobial agent, with lower free Ag(I) ions and particle size than other Ag-complexes. Moreover, it provided anti-tumour activity of most tested cell lines (in vitro), with the following sequence HCT116 > PC3 > HePG 2 > MCF-7 > A549 with IC50 and IC90 values of 25.8 and 54.73 µg ml-1, 45.1 and 66.7 µg ml-1, 64.3 and 110.7 µgml-1, 71.4 and 114.8 µgml-1 and 80.1 and 127.7 µgml-1, respectively. The promising effect of SC-Ag complex was also clear from its selective index versus RPE1 (normal retina cell line).

9.
Int J Biol Macromol ; 150: 228-237, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32044369

RESUMO

This work deals with assessing the efficient performance of sodium caseinate (SC) as protein-based drug delivery system of niacin (NA) than carboxymethyl cellulose (CMC). In this respect the hydrogels from complexation of chitosan with sodium caseinate (SC/Ch) or sodium carboxymethyl cellulose (CMC/Ch) were prepared. The Synthesized NA free and loaded hydrogels were characterized by many techniques for examining the interaction, morphology, swelling, encapsulation efficiency (EE) and loading (L) % of niacin, as well as cytotoxicity study. The finding data showed the promising behavior of SC/Ch hydrogel than CMC/Ch hydrogel, toward the amount of loaded NA (95.6%) and in vitro slow sustained release up to 24 h. Whereas, the entrapment efficiency of the CMC/Ch to nicotinic acid was reached 85.6%, and it possessed highly initial burst release followed by a slower release up to 24 h. At pH 7.4 (simulated intestinal fluid) both hydrogels provided higher level of releasing profile to NA than pH 2.1 (gastric fluid). The NA release from hydrogels followed Fickian and non-Fickian diffusion mechanism according to pH 7.4 and 2.1, respectively. It is interesting to note that, the data obtained are higher than those obtained from literature reported hydrogel, e.g., poly (2-hydroxyethyl methacrylate). Neutral red uptake and lactate dehydrogenase assays confirmed both hydrogels have good biocompatibility and could be used as nontoxic drug delivery system. So, we recommended SC/Ch hydrogel as an effective controlled niacin drug delivery system with reducing systemic side effects and improved intestinal targeting efficiency.


Assuntos
Celulose , Quitosana , Portadores de Fármacos , Sistemas de Liberação de Medicamentos , Hidrogéis , Niacina/administração & dosagem , Proteínas , Celulose/química , Quitosana/química , Portadores de Fármacos/química , Composição de Medicamentos , Liberação Controlada de Fármacos , Hidrogéis/química , Concentração de Íons de Hidrogênio , Cinética , Niacina/farmacocinética , Proteínas/química , Espectroscopia de Infravermelho com Transformada de Fourier
10.
R Soc Open Sci ; 6(5): 190173, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31218058

RESUMO

During the production of paper pulp, the waste water loaded with organic materials from pulping process is discharged. Therefore, water treatment should be performed before disposing of such effluent. The use of such effluent for production of activated carbon will be effective in omitting the wastewater treatment and in obtaining the product required in many industries. In this respect, this paper deals with evaluating the performance of activated carbons (ACs) produced from black liquors (BLs) as by-products from three pulping processes of rice straw (RS) and sugar-cane bagasse (SCB), namely: alkaline, sulfite and neutral sulfite, which are coded SP, SSP and NSP, respectively. Elemental analysis and thermal analysis (TGA and DTGA) are carried out on the BLs, while the surface area (S BET), micro-/mesoporous distribution, adsorption capacity of methylene blue (MB) and iodine (I2-value), as well as Fourier transform infrared spectra (FT-IR) and scanning electron micrograph (SEM) are studied on synthesizing ACs. The optimal pulping approach for achieving BL-based AC, with the following characteristics: specific surface area (S BET) ∼ 921 and 545 m2 g-1, MB adsorption capacity 238 and 370 mg g-1, and I2-value 928 and 1255 mg g-1 of BL-based ACs, are from neutral sulfite pulping of SCB (B-NSP) and RS (RS-NSP), respectively. These finding data are ascribed to the carbon content of BL, as well as greatest total volume (VT 0.786 and 0.701 cm3 g-1) together with decreasing the volume of micropores/total (38 and 48%) of BL-NSP-ACs. It is interesting to note that the AC provided from RS-NSP has greater adsorption capacity for I2 and MB than the AC produced from RS-pulp fibres.

11.
R Soc Open Sci ; 6(7): 190579, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31417754

RESUMO

To recommend the beneficial effect of the pulping process on enhancing agro-wastes as precursors for the production of high-performance activated carbons (ACs), different pulping methods (alkali, sulfite and neutral sulfite) were applied on two available Egyptian agriculture by-products (rice straw and sugar cane bagasse), using the one-step pyrolysis method and H3PO4 activating agent. The adsorption performance of the different prepared ACs was evaluated in terms of Iodine Numbers and their sorption properties for removing the methylene blue (MB) from aqueous solutions. The corresponding sorption processes were also analysed using Lagergren first order, pseudo-second order and intraparticle diffusion models. Data revealed that the applied pulping conditions were effective for removing the non-cellulosic constituents of agro-residues. This was demonstrated by the hydrogen/carbon and oxygen/carbon ratios, thermal stability and IR-measurements of the final pulps. These data were effective on the particular sorption properties of RS and SCB-based ACs. Interestingly, the pulping process is a profound modification of the SCB-based fibres, on which it induced a clear increase of the specific surface areas of the corresponding ACs even though they had an impact on the sorption of MB and iodine. These values are superior to the reported data on agro-based ACs with H3PO4 activators. Pulping processes therefore play a dual role in the sorption properties of ACs. The first important role is the impact on the specific surface areas and the second impact is a profound modification of the surface chemistry of the ACs. Therefore, SCB-based ACs can be seen as an economical breakthrough product, and an alternative to the high-cost commercial ACs for the purification of industrial wastewaters.

12.
Glob Chall ; 3(10): 1800097, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31592331

RESUMO

This work deals with using a novel approach for securing and dating printed documents, which will detect any forging crime present. In this respect, the coded dots matrices (machine identification code (MIC)) for the used printers are extracted via a binary system of base 2 (0, 1). The UV ink used in the printing process is prepared from novel fluorescence compounds together with polyvinyl alcohol. Different Xerox models of color laser printers are used for printing the document designs. The data obtained reveal that the investigated approach is succeeded in specifying the date of the printing process together with translating the embedded data of the printer to visible information, which can be tracked under a UV lamp. This innovative approach will assist workers in examining the questioned document by specifying the authorized date and position of printed documents from the MIC.

13.
R Soc Open Sci ; 5(7): 171578, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30109042

RESUMO

This work deals with optimizing the conditions of pyrolysis and type of activator to upgrade the use of Casuarina equisetifolia fruit waste (CFW) as available and a potential precursor, in production of activated carbon (AC). In this respect, the route of activation was carried out through one- and two-step pyrolysis processes, using different chemical activating agents, such as H3PO4, KOH and ZnCl2. The performance of the CFW-based ACs is assessed by estimating the physico-chemical characteristics (pH, electrical conductivity, bulk density and hardness), surface morphology and scanning electron microscopy, together with carbon yield, surface area and adsorption performance of pollutants in aqueous medium (methylene blue, iodine and molasses colour removal efficiencies). The results show that the two-step activation process was more effective than one-step activation for providing high adsorption performance CFW-based ACs. The maximum Brunauer-Emmett-Teller surface area 547.89 m2 g-1 was produced by using H3PO4 activating agents, and applied two-step pyrolysis. According to the American Water Work Association and based on bulk density of the investigated ACs, we recommend that most of produced ACs are suitable for treating waste water.

14.
Int J Biol Macromol ; 107(Pt A): 1364-1372, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29155155

RESUMO

This article deals with evaluating the role of cellulose origin, from wood and non-wood, on preparing green CMC-Ag complex as biological active agent. Viscose pulp as well as bagasse and rice straw pulps were used in preparation of CMCs, followed by complexation with AgNO3. The complex structure (free-Ag, IR-spectra and TGA), morphology (TEM), antibiological and anti-tumor activities were studied. The data revealed that, the main interaction between CMC and silver is occurred via carboxylate groups and ether link of 1ry alcohol, with formation stable 5-membered ring structure. For the case of RS-based CMC-Ag complex the interaction between COO groups and silica included RS is also possible, via hydrogen bonds. These complexes have anti-biological especially towards gram positive bacteria (B.subtilis, NCID-3610), and uni- and multi cellular fungi. AgNPs from viscose (VCMC-Ag complex) has relatively higher anti-tumor activity for breast cancer MCF-7 in vitro than bagasse-based CMC-Ag complex (BCMC-Ag complex) with IC50 128µg/ml (as Ag). It is interesting to note that; viscose-based CMC-Ag complex (VCMC-Ag) has higher efficient behaviour as bioactive agent than literature reported agents, e.g., Pyridine derivative (∼300µg/ml).


Assuntos
Antibacterianos/química , Carboximetilcelulose Sódica/química , Bactérias Gram-Positivas/efeitos dos fármacos , Substâncias Macromoleculares/química , Antibacterianos/síntese química , Antibacterianos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Carboximetilcelulose Sódica/síntese química , Carboximetilcelulose Sódica/farmacologia , Proliferação de Células/efeitos dos fármacos , Celulose/química , Fungos/efeitos dos fármacos , Fungos/patogenicidade , Bactérias Gram-Positivas/patogenicidade , Química Verde , Humanos , Células MCF-7 , Substâncias Macromoleculares/síntese química , Substâncias Macromoleculares/farmacologia , Nanopartículas Metálicas/química , Prata/química
15.
R Soc Open Sci ; 5(3): 171964, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29657796

RESUMO

A variety of fluorescence-active fluorinated pyrazolines 13-33 was synthesized in good yields through cyclocondensation reaction of propenones 1-9 with aryl hydrazines 10-12. Some of the synthesized compounds provided promising fluorescence properties with quantum yield (Φ) higher than that of quinine sulfate (standard reference). Quantitative structure-property relationship studies were undertaken supporting the exhibited fluorescence properties and estimating the parameters governing properties. Five synthesized fluorescence-active pyrazolines (13, 15, 18, 19 and 23) with variable Φ were selected for treating two types of paper sheets (Fabriano and Bible paper). These investigated fluorescence compounds, especially compounds 19 and 23, provide improvements in strength properties of paper sheets. Based on the observed performance they can be used as markers in security documents.

16.
Carbohydr Polym ; 153: 641-651, 2016 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-27561536

RESUMO

The present study deals with synthesizing novel cellulose derivative, from modifying the carboxymethyl cellulose with amino phenylpropanoic acid (CMC-APP). The synthesized CMC-APP was evaluated as biological and anti-cancer active compound. The molecular structures of this active compound were built using the HyperChem program 7.5, together with conventional analysis (nitrogen content, FT-IR, and non-isothermal TGA analysis). Optimizing the CMC/APPA ratio was carried out as preliminary assessment step, via undetected antimicrobial activity measurement. The TEM study showed that, the synthesized cellulose CMC-APP derivative in the nano-scale particle size (range from 12.5 to 89.3nm). Among all the tested microorganisms and MCF-7 breast cancer cells, the synthesized nano-cellulose derivative is possible used as safety medicine for microbial infections and cancers. The minimal inhibitory concentration (MIC) for Gram-positive bacteria, and gram-negative bacteria are 48.82µg/mL and 97µg/mL, respectively. While, the unicellular fungi and filamentous fungi are 12.2µg/mL and 97.65µg/mL, respectively. The cytotoxic index (IC50) for MCF-7 breast cancers is 50µg/mL. Moreover, the computational study of ADMET (absorption, distribution, metabolism, elimination and toxic) properties, of the molecules showed that, this investigated nano-compound is good oral bioavailability.


Assuntos
Antibacterianos/química , Antifúngicos/química , Antineoplásicos/química , Carboximetilcelulose Sódica/análogos & derivados , Fenilpropionatos/química , Aminação , Antibacterianos/síntese química , Antibacterianos/farmacologia , Antifúngicos/síntese química , Antifúngicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Bactérias/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Carboximetilcelulose Sódica/síntese química , Carboximetilcelulose Sódica/farmacologia , Fungos/efeitos dos fármacos , Humanos , Células MCF-7 , Modelos Moleculares , Micoses/tratamento farmacológico , Fenilpropionatos/síntese química , Fenilpropionatos/farmacologia
17.
Carbohydr Polym ; 99: 508-16, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24274537

RESUMO

Papers coated with caseinate and caseinate/chitosan bilayer films were developed. Caseinate, chitosan and caseinate/chitosan films were preliminary characterized by FTIR spectroscopy and thermal stability analyses. The effects of coating weight, caseinate concentration (7%, 10%, and 12%, w/w), and coating application methods (single layer and bilayer) on the physical and mechanical properties of coated papers were studied. Increasing the concentration of caseinate led to a decrease in water vapor permeability (WVP) of the resulting coated paper sheets. Chitosan significantly (p<0.05) increased the elongation at break (%E) of coated paper. However, the application of chitosan as a second layer on wet or dry caseinate films did not significantly affect (p>0.05) the tensile strength (TS) of coated paper. The greatest reduction in paper WVP is achieved by addition of a chitosan layer to the dried preformed caseinate-coated paper.


Assuntos
Caseínas/química , Quitosana/química , Embalagem de Alimentos , Papel , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Permeabilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Vapor/análise , Resistência à Tração
18.
Bioresour Technol ; 101(12): 4662-6, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20153181

RESUMO

The objective is to evaluate the primary mechanical and physical properties of particleboard made from hammer-milled rice straw particles of six different categories and two types of resins. The results show the performance of straw particleboards is highly dependent upon the straw particle size controlled by the opening size of the perforated plate inside the hammer-mill. The static bending and internal bonding strength of polymeric diphenylmethane diisocyanate (pMDI) resin-bonded boards initially increase then decrease with decreased particle size. The thickness swelling, water absorption, and linear expansion of particleboards decrease with increasing particle size. Compared with pMDI resin-bonded panels, the rice straw particleboard bonded using urea-formaldehyde resin exhibits much poorer performance. The optimized panel properties, obtained when using 4% pMDI and straw particles hammer milled with a 3.18 mm opening perforated plate, exceeded the M-2 specification of American National Standard for Wood Particleboard.


Assuntos
Materiais de Construção/análise , Oryza/química , Resíduos/análise , Absorção , Módulo de Elasticidade , Teste de Materiais , Tamanho da Partícula , Água/química
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