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1.
ChemSusChem ; : e202400378, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38570922

RESUMO

Converting lignin into aromatic chemicals is a promising strategy for the high-value utilization of lignocellulosic feedstock. However, the inherent heterogeneity of lignin poses a significant obstacle to achieving efficient conversion and optimal product yields within bio-refinery systems. Herein, we employed a one-step fractionation method to enhance lignin homogeneity and utilized the THF/DMSO-EtONa (tetrahydrofuran/dimethyl sulfoxide-sodium ethoxide) system to depolymerize the fractionated lignin. Three protic and three aprotic solvents were used for fractionation. The impact of the solvent properties on the structure and the depolymerization efficiency of the fractionated lignin was investigated. Methanol-fractionated lignin generated the benzoic acid compounds with a yield of 30 wt%, 50 % higher than that of the unfractionated lignin. The polarities (δP), hydrogen bonding abilities (δH), and viscosities (η) of selected protic solvents showed strong linear correlation with molecular weight (Mw), polymer dispersity index (PDI), and syringyl/guaiacyl ratio (S/G ratio) of the fractionated lignin, as well as the total yield of benzoic acid compounds derived from the ß-O-4 bond cleavage. This study elucidates the relationship between solvent properties and lignin structure and proposes a promising approach for refining lignin to enhance utilization efficiency, thereby presenting a potential strategy for value-added application of complex lignin polymers.

2.
Carbohydr Polym ; 327: 121646, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38171671

RESUMO

Achieving excellent ultraviolet (UV) blocking properties and maintaining high light transmittance are highly challenging. In this study, a facile and green polymer-assisted vacuum filtration strategy was used to prepare cellulose nanocrystal (CNC) one-dimensional photonic crystal (1DPhC) films with excellent UV-blocking performance and good transparency. The polymer-assisted self-assembly behaviors of CNC and the hydrogen bonding interaction between CNC, polyethylene glycol (PEG), and graphene oxide (GO) drive the homogeneous distribution and parallel alignment of GO. The UV absorption of GO and high reflection of UV resulting from the chiral nematic structure of CNCs result in excellent UV-blocking and high visible light transmission. Besides, the strong hydrogen bonding interaction among CNC, PEG, and GO endows the films with obviously increased mechanical properties. The UV-blocking and the transparency of the CNC composite films could reach 98.3 % and 60.5 %, respectively. Besides, the strain at break of the composite film reached 1.72 ± 0.11 %, which was 535.94 % of neat CNC films. The CNC composite films present great potential in the field of UV-blocking glass, sensors, anti-counterfeiting measures, radiation protection, and so on.

3.
Adv Mater ; 35(25): e2300109, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37009654

RESUMO

Maintaining a steady affinity between gallium-based liquid metals (LM) and polymer binders, particularly under continuous mechanical deformation, such as extrusion-based 3D printing or plating/stripping of Zinc ion (Zn2+ ), is very challenging. Here, an LM-initialized polyacrylamide-hemicellulose/EGaIn microdroplets hydrogel is used as a multifunctional ink to 3D-print self-standing scaffolds and anode hosts for Zn-ion batteries. The LM microdroplets initiate acrylamide polymerization without additional initiators and cross-linkers, forming a double-covalent hydrogen-bonded network. The hydrogel acts as a framework for stress dissipation, enabling recovery from structural damage due to the cyclic plating/stripping of Zn2+ . The LM-microdroplet-initialized polymerization with hemicelluloses can facilitate the production of 3D printable inks for energy storage devices.

4.
Nanoscale ; 15(11): 5469-5475, 2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36852628

RESUMO

Cellulose nanocrystal (CNC) materials grant abundant possibilities for insulation, however, their extensive application is hindered by the intrinsic tradeoff between their thermal insulating performance and mechanical properties. Here, we show that CNC aerogels with balanced thermal and mechanical performance can be fabricated via a 1 nm metal oxide cluster (phosphotungstic acid, PTA)-assisted unidirectional freeze-drying processing. The as-prepared hybrid aerogels with hierarchical porous structures consisting of layer-by-layer CNC nanosheets enable the decoupling of the strengthening of mechanical properties and the enhancement of thermal insulating capabilities. Within layered structures, the surface-doped nanosized PTA clusters with negative charges behave as dynamic physical cross-linking points, and continuous networks of PTA-doped CNC can be formed via multiple supramolecular interactions (e.g., electrostatic attractions and hydrogen bonds). The afforded stable three-dimensional network structures are able to withstand externally applied forces and large deformations, endowing the aerogels with excellent mechanical performance. Moreover, the inter-layer gap is dominated by nanopores, endowing much lower thermal conductivities along the radial direction in comparison to the axial direction. The addition of PTA clusters also contributes to the obvious enhancements of the fire-retardant properties. Our discoveries provide a facile approach for the design and scalable production of CNC-based insulation materials with optimized mechanical properties and additional fire-retardant properties.

5.
Int J Biol Macromol ; 225: 1350-1360, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36436596

RESUMO

In this study, one high-performance hemicelluloses (HC)-based sprayable and biodegradable pesticide mulch film was developed. Firstly, HC was transesterified with vinyl acetate (VA) to improve its solubility and film-forming ability. Then abamectin (ABA) was encapsulated by ß-cyclodextrin (ß-CD) to endow mulch film persistent anti-pesticide activity. After that, sodium alginate (SA) and gelatin were added to develop the mechanical performances of the mulch film. As a result, the obtained mulch film showed good characteristics, with optimum mechanical strength, elongation at break, water vapor permeability (WVP), swelling ratio (SR), and weight loss (biodegradability) of 7.9 ± 0.3 MPa, 43.6 ± 2.0 %, 2.1 ± 0.1 × 10-11 g mm m-2 s-1 kPa-1, 73.8 ± 2.0 %, and 69.3 %, respectively. After covering with mulch film, the soil moisture and temperature were developed to 90.8 % and 19.3 ± 0.2 °C, respectively, which could facilitate Chinese cabbage growth, with optimum germination rate of 98.6 ± 6.4 %.


Assuntos
Praguicidas , Polissacarídeos , Solo , Alginatos
6.
Front Bioeng Biotechnol ; 10: 989893, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36246371

RESUMO

Cellulose-based functional composite films can be a good substitute for conventional plastic packaging to ensure food safety. In this study, the semi-transparent, mechanical strengthened, UV-shielding, antibacterial and biocompatible films were developed from hydroxyethyl cellulose Polyvinyl alcohol (PVA) and ε-polylysine (ε-PL) were respectively used as reinforcing agent and antibacterial agent, and chemical cross-linking among these three components were constructed using epichlorohydrin The maximum tensile strength and elongation at break were 95.9 ± 4.1 MPa and 148.8 ± 2.6%, respectively. TG-FTIR and XRD analyses indicated that chemical structure of the composite films could be well controlled by varying component proportion. From UV-Vis analysis, the optimum values of the percentage of blocking from UV-A and UV-B and ultraviolet protection factor values were 98.35%, 99.99% and 60.25, respectively. Additionally, the composite films exhibited good water vapor permeability, swelling behavior, antibacterial activity and biocompatibility. In terms of these properties, the shelf life of grapes could be extended to 6 days after packing with the composite film.

7.
Biomacromolecules ; 23(8): 3329-3335, 2022 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-35875983

RESUMO

The fabrication of commercial cellulose nanofibrils (CNFs) into arrays with long-range ordering is of great significance for their extended applications, which, however, is severely hindered by their high disorder, aggregation, and hornified features. Herein, sub-nanoscale anionic metal oxide clusters (phosphotungstic acid, H3PW12O40, PTA) are applied to complex with commercial CNFs (dried powder DCNF and aqueous suspension WCNF) in aqueous media, and a long-range ordered layer structure can be facilely fabricated via typical unidirectional freezing. The surface complexation of the commercial CNFs and PTA can be confirmed through the small-angle scattering studies of the complex hydrogels. The hydrogels present similar correlation lengths in small-angle X-ray and neutron scattering measurements, suggesting the homogeneous distribution of PTA along the commercial CNFs. This gives rise to the negatively charged surface feature and further leads to strong repulsion among the commercial CNFs. Due to the disparity in sizes, the influence of PTA on the density of hydrogel networks is suppressed, and the network density is mainly dependent on the mass content of CNFs. The studies provide guidance to fabricate hydrogels with catalytic and photosensitive properties and also to design and stabilize long-range ordered structured aerogels during the removal of the nonfreezing bound water absorbed by the commercial CNFs after unidirectional freezing. This facile strategy shows great potential to broaden the application of commercial CNFs in thermal insulators, super-adsorbent materials, and supercapacitors in electrical devices.


Assuntos
Celulose , Nanofibras , Celulose/química , Hidrogéis/química , Nanofibras/química , Água
8.
Carbohydr Polym ; 291: 119479, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35698320

RESUMO

The increasing environmental burden generated by disposable plastic wastes makes the development of sustainable substitute materials an emergent task. As one of the most abundant bioresources, chitosan (CS) has been considered as a potential candidate for plastic substitution. Conventionally, CS-based materials are fabricated through a solution-processing procedure due to the high crystallinity of CS. Herein, we designed a CS-based material via integrating CS into the network of polyimine (PI), which shows thermomechanical processability similar to plastics. Strong interactions were achieved through dynamic imine bond and hydrogen bond and thus formed a thermo-processable dynamic composite network. These CS-based plastic substitutes exhibit exceptional mechanical performances, excellent thermal/chemical stability, and a series of self-adaptiveness, including re-healing, reprocessing and multi-layer laminating. Notably, CPs can be easily degraded and 100% recycled for the production of next-generation materials. This work provides an alternative route to produce green and sustainable biomass materials as a plastic substitute.


Assuntos
Quitosana , Plásticos , Biomassa , Quitosana/química , Ligação de Hidrogênio , Reciclagem
9.
Molecules ; 27(9)2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35566131

RESUMO

Polyoxometalate (POM) presents great potential in oxidative desulfurization (ODS) reaction. However, the high dissolubility of POM in common solvents makes it difficult to recycle. Besides, the small specific surface area of POM also limits the interaction between them and the substrate. Depositing polyoxometalates onto three-dimensional (3D) network structured materials could largely expand the application of POM. Here, the surfaces of cellulose nanofibrils (CNFs) were modified with very few (3-Aminopropyl) trimethoxysilane (APTS) to endow positive charges on the surfaces of CNFs, and then phosphotungstic acid (PTA) was loaded to obtain the aerogel A-CNF/PTA as the ODS catalyst. FT-IR indicated the successful deposition of PTA onto aminosilane modified CNF surfaces. UV-VIS further suggested the stability of PTA in the aerogels. BET and SEM results suggested the increased specific surface area and the relatively uniform 3D network structure of the prepared aerogels. TGA analysis indicated that the thermal stability of the aerogel A-CNF/PTA50% was a little higher than that of the pure CNF aerogel. Most importantly, the aerogel A-CNF/PTA50% showed good catalytic performance for ODS. Catalysis results showed that the substrate conversion rate of the aerogel A-CNF/PTA50% reached 100% within 120 min at room temperature. Even after five cycles, the substrate conversion rate of the aerogel A-CNF/PTA50% still reached 91.2% during the dynamic catalytic process. This work provides a scalable and facile way to stably deposit POM onto 3D structured materials.


Assuntos
Celulose , Nanofibras , Ânions , Celulose/química , Nanofibras/química , Estresse Oxidativo , Polieletrólitos , Espectroscopia de Infravermelho com Transformada de Fourier
10.
Bioresour Technol ; 344(Pt B): 126298, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34748982

RESUMO

A pretreatment method combining ball-milling, ultrasound, and hydrothermal treatment was developed to produce xylooligosaccharides (XOS) and glucose with a high yield from corn stover. Under optimal conditions, the yield of XOS reached 80.40%, and the functional XOS (X2-X4) took up to 26.97%. Small amount of inhibitors were formed during the hydrothermal process. Enzymatic hydrolysis of the hydrothermally pretreated residue gave 92.60% yield of glucose, leaving lignin as the final residue which accounted for 66.82% of native lignin. The correlations between the yield of glucose and the physio-chemical properties of corn stover, such as crystalline index, particle size, and the removal of xylan, were established to understand the recalcitrance removal during the pretreatment process. Results demonstrate that this combined pretreatment method is a green and effective process to selectively separate the hemicellulose fractions and improve both production of XOS and glucose yield.


Assuntos
Glucose , Oligossacarídeos , Hidrólise , Lignina , Xilanos
11.
Molecules ; 26(18)2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34577185

RESUMO

Biomass, as the most abundant and sustainable resource on the earth, has been regarded as an ideal carbon source to prepare various carbon materials. However, manufacturing shape-memory carbon aerogels with excellent compressibility and elasticity from biomass remains an open challenge. Herein, a cellulose-derived carbon aerogel with an anisotropic architecture is fabricated with the assistance of graphene oxide (GO) through a directional freeze-drying process and carbonization. The carbon aerogel displays excellent shape-memory performances, with high stress and height retentions of 93.6% and 95.5% after 1000 compression cycles, respectively. Moreover, the carbon aerogel can identify large ranges of compression strain (10-80%), and demonstrates excellent current stability during cyclic compression. The carbon aerogel can precisely capture a variety of biological signals in the human body, and thus can be used in wearable electronic devices.


Assuntos
Grafite/química , Anisotropia , Biomassa , Carbono/química , Celulose/química , Elasticidade , Géis/química , Humanos , Porosidade
12.
Bioresour Technol ; 337: 125327, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34118741

RESUMO

The aim of this work was to develop a feasible ball mill-assisted alkaline peroxide pretreatment followed by stepwise hydrolysis to improve the yield of xylo-oligosaccharides (XOS) and fermentable sugars. The hydrogen peroxide charge, ball-milling time, and solid-to-liquid ratio affected the compositions, particle sizes, morphology, and crystallinity of the corn stover, directly improving the following hydrolytic efficiency. The optimal pretreatment was with 0.45 g/g (H2O2: substrate) and 1:3 solid-to-liquid ratio (w/v) for 1.0 h ball-milling, resulting in 84.29% delignification. Physicochemical properties of the pretreated samples were characterized and their correlations to the enzymatic hydrolysis were revealed. Compared with one-step cellulase hydrolysis, the two-step xylanase-cellulase hydrolysis of the pretreated corn stover showed significant advance in preparing XOS, producing 69.65% (on the base of xylan content in pretreated sample) of XOS, along with 20.55% xylose, 68.94% glucose, and 21.15% gluco-oligosaccharides. The yield of XOS was 2-7 times higher than those in previous studies.


Assuntos
Celulase , Zea mays , Peróxido de Hidrogênio , Hidrólise , Oligossacarídeos , Peróxidos , Açúcares
13.
Molecules ; 26(5)2021 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-33799950

RESUMO

It is challenging work to develop a low-cost, efficient, and environmentally friendly Cr(VI) adsorbent for waste water treatment. In this paper, we used hemicelluloses from chemical fiber factory waste as the raw material, and prepared two kinds of carbon materials by the green hydrothermal method as adsorbent for Cr(VI). The results showed that hemicelluloses hydrothermally treated with citric acid (HTC) presented spherical shapes, and hemicelluloses hydrothermally treated with ammonia solution (HTC-NH2) provided spongy structures. The adsorption capacity of the samples can be obtained by the Langmuir model, and the adsorption kinetics could be described by the pseudo-second-order model at pH 1.0. The maximum adsorption capacity of HTC-NH2 in the Langmuir model is 74.60 mg/g, much higher than that of HTC (61.25 mg/g). The green hydrothermal treatment of biomass with ammonia solution will provide a simple and feasible way to prepare adsorbent for Cr(VI) in waste water treatment.


Assuntos
Cromo/isolamento & purificação , Polissacarídeos/química , Carbono/química , Cromo/química , Ácido Cítrico/química , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Difração de Raios X
14.
Carbohydr Polym ; 260: 117835, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33712172

RESUMO

Bacterial breeding is the main cause of food perishability, which is harmful to human health. Silver nanoparticles (AgNPs) are one of the most widely used antimicrobial agents, but they are easy to release and cause cumulative toxicity. In this work, with corn stalk as green reductant and GO as template, a simple electrostatic self-assembled sandwich-like chitosan (CS) wrapped rGO@AgNPs nanocomposite film (CS/rGO@AgNPs) was synthesized to achieve stabilizing and controlled-release of AgNPs. The results showed that the the CS/rGO@AgNPs film continued releasing AgNPs for up to 14 days, and the final release amount of silver nanoparticles was only about 1.9 %. More importantly, the nanocomposite film showed durable antibacterial effect and good antibacterial activity against E. coli and S. aureus, and they showed no toxicity to cells. Hence, the nanocomposite film has potential application as an effective and safe packaging material to prolong the shelf life of food products.


Assuntos
Antibacterianos/química , Quitosana/química , Grafite/química , Nanopartículas Metálicas/química , Nanocompostos/química , Antibacterianos/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Escherichia coli/efeitos dos fármacos , Humanos , Nanocompostos/toxicidade , Prata/química , Solubilidade , Staphylococcus aureus/efeitos dos fármacos , Resistência à Tração
15.
Carbohydr Polym ; 246: 116489, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32747228

RESUMO

The aim of this study was to investigate the physicochemical properties of chitosan (CS) based composite films with the incorporation of hemicelluloses (HC). Films were obtained via direct immersion method and characterized in terms of structural and morphological properties by FT-IR, XRD, XPS, SEM and EDS. By combining with the increased HC loading efficiency (L) and swelling property (S) of films with the increased HC content to 5%, this study proved the increased hydrogen bond interactions between CS and HC. Films with the tensile strength of 32.81 ± 4.97 MPa and elongation at break of 39.63 ± 4.67% were obtained with 3% HC and 20% glycerol (GC). The water vapor permeability (WVP) of films developed with the increased HC and GC contents, while the oxygen permeability (OP) decreased. Moreover, antibacterial testing indicated that all films exhibited the increased growth inhibition against E. coli and S. aureus as increasing TiO2 content.


Assuntos
Quitosana/química , Filmes Comestíveis , Polissacarídeos/química , Antibacterianos/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Glicerol/química , Ligação de Hidrogênio , Oxigênio/química , Permeabilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Vapor , Resistência à Tração , Titânio/química , Titânio/farmacologia , Difração de Raios X
16.
Carbohydr Polym ; 229: 115336, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826458

RESUMO

An alternative transesterification with vinyl laurate (VL) was applied for chemical modification of hemicelluloses (HC) to prepare functional packaging films. Successful transesterification was confirmed by FT-IR and NMR. Semitransparent laurated HC (LHs) films were prepared by solvent casting method. SEM indicated the ordered honeycomb-patterned surface and the dense cross section of LHs films. The LHs films exhibited excellent hydrophobicity with water contact angle about 120° and the enhanced mechanical properties with tensile strength and elongation at break as 33.94 ± 3.09 MPa and 22.41 ± 2.87%, respectively. The water vapor permeability (WVP) and oxygen permeability (OP) values of LHs films ranged from 1.59 ± 0.07 to 2.23 ± 0.11 (10-10·g/m·s·Pa) and 1.21 ± 0.04 to 4.24 ± 0.30 (cm3·µm/m2·d·kPa), respectively. Moreover, the films had acceptable antioxidant activity. In terms of these properties, the shelf life of green chilies could be largely extended to 15 days after packing with LHs films.


Assuntos
Embalagem de Alimentos , Líquidos Iônicos/química , Lauratos/química , Polissacarídeos/química , Capsicum , Esterificação , Espectroscopia de Ressonância Magnética , Oxigênio/química , Permeabilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Vapor , Água/química
17.
Polymers (Basel) ; 11(12)2019 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-31795517

RESUMO

Recently, the nanofiber materials derived from natural polymers instead of petroleum-based polymers by electrospinning have aroused a great deal of interests. The lignocellulosic biomass could not be electrospun into nanofiber directly due to its poor solubility. Here, sugarcane bagasse (SCB) was subjected to the homogeneous esterification with different anhydrides, and the corresponding esterified products (SCB-A) were obtained. It was found that the bead-free and uniform nanofibers were obtained via electrospinning even when the mass fraction of acetylated SCB was 70%. According to the thermogravimetric analyses, the addition of SCB-A could improve the thermal stability of the electrospun composite nanofibers. More importantly, in contrast to the pure polyacrylonitrile (PAN) based carbon nanofiber, the SCB-A based carbon nanofibers had higher electrical conductivity and the surface N element content. In addition, the superfine carbon nanofiber mats with minimum average diameter of 117.0 ± 13.7 nm derived from SCB-A were obtained, which results in a larger Brunauer-Emmett-Teller (BET) surface area than pure PAN based carbon nanofiber. These results demonstrated that the combination of the homogeneous esterification and electrospinning could be a feasible and potential way to produce the bio-based carbon nanofibers directly from lignocellulosic without component separation.

18.
Carbohydr Polym ; 224: 115197, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472838

RESUMO

In order to obtain new retention and drainage-aid agent, exfoliated xylan-g-QCS/MMT nanocomposites were prepared. Briefly, quaternized chitosan azide (QCS-N3) was intercalated into the layer of montmorillonite (MMT) to enlarge the interplanar gallery; subsequently, QCS-N3/MMT was grafted with xylan by click chemistry, during this process, the interlayer space of MMT was further increased till exfoliated. Subsequently, the exfoliated xylan-g-QCS/MMT was evaluated to act as retention and drainage-aid agent. The initial critical concentration of xylan-g-QCS/MMT was 0.01 mg/g in the adsorption behavior on cellulosic substrate. The maximum flocculation efficiency for CaCO3 was 37.41%. When dosages were about 0.01 mg/g, oSR values were the lowest. All these results show that retention and drainage-aid performance of xylan-g-QCS/MMT was better than only xylan, QCS or MMT. The study combined three kinds of natural resources to prepare organic/inorganic nanocomposites, providing a new method to develop papermaking additive and achieve high-value utilization of natural resources.

19.
Int J Biol Macromol ; 134: 740-748, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31100399

RESUMO

This study evaluated the solubility of low-processed wood fibers produced from a low temperature acid hydrotropic fractionation (AHF) in an ionic liquid (IL) 1,5-diazabicyclo[4.3.0]non-5-enium acetate (DBNH[OAc]. Unbleached wood fibers produced from AHF using p-Toluenesulfonic acid (p-TsOH) with or without post-treatments with lignin and hemicelluloses content up to 15% and 25%, respectively, were dissolved directly into the IL DBNH[OAc]. Post-AHF treatments using dilute alkaline and glycerol swelled the cellulose and partially removed residual lignin resulting in improved dissolution. Semi-quantitative 2D HSQC NMR analyses revealed that the undissolved wood fiber residues were enriched with G units and condensed S units (Scond), demonstrating, as expected, that G units and condensed lignin substructures have a negative effect on dissolution in DBNH[OAc]. Therefore, AHF with rapid fractionation at low temperatures offers a promising advantage over existing high temperature pulp dissolving fiber (PDF) processes in terms of reducing energy input, lowering lignin content as well as reducing lignin condensation for producing man-made cellulosic fibers (MMCF).


Assuntos
Líquidos Iônicos/química , Lignina/química , Madeira/química , Álcalis , Fenômenos Químicos , Glicerol , Interações Hidrofóbicas e Hidrofílicas , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Compostos Fitoquímicos/química , Solubilidade , Têxteis/análise
20.
Sci Rep ; 9(1): 7300, 2019 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-31086221

RESUMO

The renewable resource as a major feedstock to prepare porous carbon has showed many advantages compared to fossil-based materials. This study proposes a new strategy to synthesize palladium nanoparticles (Pd NPs)-supported porous carbon, utilizing both the chemical reactivity and the carbon-rich 3D network of lignin. The Pd NPs-supported porous carbons were prepared in one-pot synthesis, with Pd(NH3)2Cl2 as precursor, lignin as reducing and stabilizing agents of Pd NPs, nano SiO2 as hard-template, followed by carbonization and removal of the template. The results reveal a positive effect of Pd precursor dosage on the development and excellent texture of the Pd NPs-supported porous carbon. Accordingly, the synthesized porous carbon was proved to have large micropore volume and good micro-mesopore porous structure, revealing it a promising hydrogen adsorbent.

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