Cross-linked Cellulose Research Articles

Impact of lignin–carbohydrate complex (LCC) linkages on cellulose pyrolysis chemistry

The prevalence of covalent lignin–carbohydrate complex (LCC) bonds likely foster inter-moiety reaction pathways, marked by significant kinetic and thermochemical barriers in the intra-moiety cellulose decomposition within LCC.

Dual cross-linked cellulose based hydrogel films

Polymeric hydrogel films, and the associated structural assembly mechanisms, endow them with exceptional capabilities for applications in wider energy paradigm, biomedicine and chemical biology. Cross linking chemistry adds extra handles...

Cross-Linked Cellulose Nanofibril Aerogel with Multiscaled Pores and Dual Wettability for Emulsion Separation

Cross-Linked Cellulose Nanofibril Aerogel with Multiscaled Pores and Dual Wettability for Emulsion Separation

Новый гидрогелевый комплекс с иммобилизованными клетками микроводорослей для удаления аммоний и фосфат-ионов из сточных вод

The aim of the work was to create a stable hydrogel complex containing microalgae cells to remove ammonium and phosphate ions from an experimental solution simulating domestic wastewater. A new polymer matrix based on sodium alginate and carboxymethyl cellulose, polyacrylic acid, retained the integrity of the structure in a solution with a high content of ammonium and phosphate ions, and also proved to be resistant to alkali metals. To increase the stability of hydrogel complexes, we proposed an increase in the number of chemical bonds in the polymer environment due to the crosslinking of alginate and carboxymethyl cellulose with Ca2+ and Fe3+ ions, as wellпа as the introduction of an additional external stabilizer – cationic polyacrylamide. Due to the combination of several polymers, only slight swelling was observed and, as a result, the preservation of the hydrogel matrix in integrity for a long time. The two most commonly used algae in biotesting were selected for the experiment: Tetradesmus obliquus and Chlorella vulgaris from the live microalgae strains collection of the Institute of Biology (Syktyvkar, Russia). The formation conditions of the hydrogel complex made it possible to preserve the viability, reproduction and development of the microalgae cells in the polymer matrix. The cell viability of both cultures was over 95%. It was found that living cells of microalgae are mainly involved in the process of nitrogen uptake. Microalgae immobilized cells, in the presence of carbonate ions, provided the best degree of removal of ammonium nitrogen, which reached 90%. The greatest contribution to the phosphorus removal (> 95%) was made by the polymer component of the hydrogel complex.

Fe(III) cross-linked cellulose-agar hydrogel beads for efficient phosphate removal from aqueous solutions.

Fe(III) cross-linked cellulose agar beads (Fe-CLCAB) were synthesized by sol-gel method and employed as adsorbents for the removal of phosphate ions from aqueous medium. The synthesized Fe-CLCAB was characterized by its swelling property, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and UV-Vis absorption spectroscopic analysis. Batch adsorption studies were carried out to find out the optimum conditions of phosphate uptake. The adsorption process was found to fit both Langmuir and Freundlich adsorption isotherm model, pseudo-second-order kinetic model, and Elovich kinetic model. Ninety-four percent phosphate adsorption was achieved with 500 beads at pH 5. Maximum monolayer adsorption capacity was 73.13mg/g. A two-step elution process using sodium chloride solution was suitable for complete desorption of phosphate from Fe-CLCAB. Six cyclic adsorption-desorption tests were conducted using a 0.1M NaCl solution as desorbing agent. The removal efficiency of regenerated Fe-CLCAB was 42% of its original value after six cycles, which validates good stability and effectiveness of the prepared hydrogel beads. Ion exchange plays a vital role during adsorption/desorption of phosphate.

Mechanically Robust Cellulose-Based Piezoelectric Elastomer Formed by Slidable Polyrotaxane Cross-Linker.

Cellulose has great potential in the field of piezoelectricity owing to its high crystallinity; however, it exhibits low processability and poor mechanical robustness. In this study, to enhance the applicability of cellulose-based piezoelectric materials, a robust cellulose-based piezoelectric elastomer with excellent piezoelectric properties was developed by cross-linking cellulose with polyrotaxane (PR). The effects of cross-linking on the mechanical properties and crystalline structures of the resulting elastomers were investigated. The ferroelectric and piezoelectric properties were evaluated from their polarization hysteresis loops and voltage generation characteristics. eHPC25PR75 exhibited 2.7 times higher toughness (20.4 MJ m-3) than eHPC100 (7.57 MJ m-3). It also shows a power density 4.2 times higher (1.34 μW cm-2) than eHPC100 (0.321 μW cm-2). As a result, eHPC25PR75 demonstrated piezosensitivity to mechanical vibrations in a variety of devices that require mechanical robustness. These results can inform the design and development of high-performance piezoelectric devices.

Triple physical cross-linking cellulose nanofibers-based poly(ionic liquid) hydrogel as wearable multifunctional sensors

A novel triple physical cross-linking poly(ionic liquid) hydrogel, composed of poly(acrylamide-co-dodecyl methacrylate-co-1-vinyl-3-methyluracil-imidazolium chloride)/cellulose nanofibers-Ca2+ (PADV/CNFs-Ca2+), was synthesized through micellar-copolymerization followed by a solvent-soaked procedure. The synergistic interactions in polymer network (i.e. the hydrophobic association of dodecyl methacrylate moiety in surfactant micelles, the hydrogen bondings between imidazolium monomer segments and other monomer segments in polymers, and the ionic coordination between Ca2+ and -COO− on cellulose nanofibers surface) endowed the hydrogel with excellent mechanical properties, including high strength (754 kPa of tensile strength and 1905 kPa of compressive strength), outstanding stretchability (1963 %), elastic modulus (56.5 kPa) and remarkable mechanical durability (200 cycles with 500 % deformations and 100 cycles at 50 % compression strain). Besides, this hydrogel exhibited other advantages, such as satisfied conductivity (28.7 mS/cm), high strain/pressure/temperature-sensitive behavior, precise and stable signal transmission, varying degrees of antibacterial activity, and biocompatibility. Owing to the exceptional comprehensive performance, the hydrogel was then assembled as a multifunctional sensor to monitor the joint motion, vocal cord vibration, tactile sensation and body temperature with remarkable sensitivity in real time. This work offered a new strategy for the fabrication of durable, biocompatible, antibacterial and conductive materials for wearable multifunctional electronic devices.

Cross-linked cellulose beads as an eco-friendly support for ZnO/SnO2/carbon xerogel hybrid photocatalyst: Exploring the synergy between adsorption and photocatalysis under simulated sunlight

This paper explores the application of cross-linked cellulose beads as a sustainable and cost-effective support for the ZnO/SnO2/carbon xerogel hybrid photocatalyst. The application of the developed photocatalytic beads, named CB-Cat, was directed at a simultaneous adsorption/photocatalysis process, which was carried out under simulated sunlight. The characterization of the CB-Cat indicated a good dispersion of the photocatalyst of choice throughout the cellulose matrix, confirming its incorporation into the cellulose beads. Furthermore, it is possible to observe the presence of the photocatalyst on the surface of the CB-Cat, confirming its availability for the photonic activation process. The results showed that the simultaneous adsorption/photocatalysis process was optimal for enhancing the efficiency of methylene blue (MB) removal, especially when compared to the isolated adsorption process. Additionally, the regeneration of the CB-Cat between cycles was favorable toward the maintenance of the MB removal efficiency, as the process carried out without regeneration displayed significant efficiency drops between cycles. Finally, the mechanism evaluation evidenced that hydroxyl and superoxide radicals were the main responsible for the MB photocatalytic degradation during illumination with simulated sunlight.

Enhancing the mechanical properties of hydrogels with vinyl-functionalized nanocrystalline cellulose as a green crosslinker

Hydrogels have gained significant attention in scientific communities for their versatile applications, but several challenges need to be addressed to exploit their potential fully. Conventional hydrogels suffer from poor mechanical strength, limiting their use in many applications. Moreover, the crosslinking agents used to produce them are often toxic, carcinogenic, and not bio-friendly. This study presents a novel approach to overcome these limitations by using bio-friendly modified nanocrystalline cellulose as a crosslinker to prepare highly stretchable and tough thermosensitive hydrogels. The surface of nanocrystalline cellulose was modified with 3-methacryloxypropyltrimethoxysilane (MPTS) to obtain modified nanocrystalline cellulose (M-NCC) crosslinker and used during free radical polymerization of thermosensitive N-isopropyl acrylamide (NIPA) monomer to synthesize NIPA/M-NCC hydrogel. The resulting nanocomposite hydrogels exhibit superior mechanical, thermal, and temperature-responsive swelling properties compared to conventional hydrogels prepared with traditional bi-functional N, N′-methylene bis (acrylamide) (MBA) as a crosslinker. The elongation at break, tensile strength, and toughness of the NIPA/M-NCC hydrogels significantly increase and Young’s modulus decrease than conventional hydrogel. The designed M-NCC crosslinker could be utilized to improve the mechanical strength of any polymeric elastomer or hydrogel systems produced through chain polymerization.

A high-performance 3D phosphorus-doped graphene oxide adsorbent for imipramine wastewater treatment

The presence of pharmaceutical wastes in the environment has adversely impacted the marine biodiversity due to their hazardous and bioaccumulation nature. This research focussed on the development of an effective phosphorus-doped 3D graphene oxide with bentonite and carboxymethyl cellulose crosslinking (PG/BCC) for the removal of imipramine in wastewater. The impacts of single factor (adsorbent dosage, initial imipramine concentration, system temperature and contact time) on imipramine adsorption were examined by batch experiments while the interactive impacts of multiple factors and process optimisation were investigated by central composite design (CCD). The greatest adsorption capacity evaluated was 458.95 mg/g at the following CCD optimised operating parameters: 10 mg PG/BCC, 250 ppm initial concentration, 34 min contact time and 321 K temperature. The Langmuir model described well the equilibrium of imipramine adsorption whilst the pseudo-second-order model correlated closely to the kinetic data. The imipramine-PG/BCC system was spontaneous (-19.24 to −27.58 kJ/mol) and endothermic (1.23 to 14.56 kJ/mol) as evaluated from thermodynamic modelling. Characterisation of PG/BCC by various microscopy and spectroscopy analyses has validated the incorporation of imipramine into PG/BCC adsorbent. Regeneration of used PG/BCC was proven to be highly feasible with methanol eluent. Conclusively, the findings strongly advocate PG/BCC as a highly feasible and sustainable graphene-based adsorbent for imipramine separation from pharmaceutical wastewater.

Ultralight, Hydrophobic, Fire-Resistant, and Highly Thermally Insulating Aerogel by Cross-Linking Cellulose Nanofiber with Tannin and Adenosine Triphosphate

Ultralight, Hydrophobic, Fire-Resistant, and Highly Thermally Insulating Aerogel by Cross-Linking Cellulose Nanofiber with Tannin and Adenosine Triphosphate

A novel formulation of triethyl orthoformate mediated durable, smart and antibacterial chitosan cross-linked cellulose fabrics

Antibacterial, durable and smart cotton fabrics was developed using chitosan-based formulation. The cellulose was covalently cross-linked with chitosan using TEOF. The antibacterial activity of prepared smart fabrics and CS was studied against S. aureus and E. coli strains. The FTIR, SEM and XRD were employed to confirm the linkage of CS molecules with cellulose in cotton fabrics. The CS of 160 KDa extracted from shrimp shell showed the optimum antibacterial activity. The prominent asymmetric, symmetric alkyl CH peaks of CS were shifted to 2930 and 2845 (cm−1), respectively. Moreover, the shifted peaks at 1590 and 1400 (cm−1) indicate the CO stretching and NH2 bending bands of CS, respectively. This confirm the existence of new imine functional group that was generated after cross-linking of NH2 groups of CS. The SEM results showed more uniform morphology of TEOF cross-linked fabrics versus CS coated fabrics, which revealed a promising microbial growth inhibition activity. The TEOF as a cross-linker has been unveiled, showcasing the effectiveness of this innovative crosslinking approach. The fabric treated with cross-linked CS exhibited remarkable antibacterial properties that endured even after undergoing 30 washing cycles. These antibacterial textiles possess substantial commercial potential across a diverse range of industries.

Crosslinking of Bacterial Cellulose toward Fabricating Ultrastretchable Hydrogels for Multiple Sensing with High Sensitivity

Crosslinking of Bacterial Cellulose toward Fabricating Ultrastretchable Hydrogels for Multiple Sensing with High Sensitivity

Fabrication of a novel bio-polymer adsorbent with high adsorptive capacity towards organic dyes

A novel adsorbent, CMC-T-CH, was fabricated by crosslinking of carboxymethyl cellulose (CMC) and chitosan (CH) with triethylenetetramine. The adsorbent's efficacy in removing the hazardous dyes, Direct blue (DB) and Congo red (CR), was investigated. Different physical, chemical, and biological methods have been employed to eliminate CR and DB dyes from aqueous solution, and adsorption has shown potential in eradicating these dyes effectively. Various characterization methods were employed to investigate the physicochemical characteristics of CMC-T-CH. The removal process was performed at optimized conditions of pH 6 for CR and pH 5 for DB at the temperature of 35 °C, resulting in maximum removal efficiencies of 99 % and 98.33 % for CR and DB, respectively. Langmuir isotherm and pseudo-second-order kinetic mathematical models were utilised to analysed the interaction of adsorbate and adsorbent during the removal process. The maximum theoretical adsorptive capacities of 519.53 and 534.25 mg/g were achieved for CR and DB removal, respectively. The regeneration study revealed that the dye-loaded CMC-T-CH could be reused several times. The phytotoxicity assay showed that the germination of Vigna mungo seeds improved after the removal treatment, thus confirming the potential of CMC-T-CH in the elimination of CR and DB.

Synthesis of Cellulose-Poly(Acrylic Acid) Using Sugarcane Bagasse Extracted Cellulose Fibres for the Removal of Heavy Metal Ions.

In this study, sugarcane bagasse (SCB) was treated with sodium hydroxide and bleached to separate the non-cellulose components to obtain cellulose (CE) fibres. Cross-linked cellulose-poly(sodium acrylic acid) hydrogel (CE-PAANa) was successfully synthesised via simple free-radical graft-polymerisation to remove heavy metal ions. The structure and morphology of the hydrogel display an open interconnected porous structure on the surface of the hydrogel. Various factors influencing batch adsorption capacity, including pH, contact time, and solution concentration, were investigated. The results showed that the adsorption kinetics were in good agreement with the pseudo-second-order kinetic model and that the adsorption isotherms followed the Langmuir model. The maximum adsorption capacities calculated by the Langmuir model are 106.3, 333.3, and 163.9 mg/g for Cu(II), Pb(II), and Cd(II), respectively. Furthermore, X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectrometry (EDS) results demonstrated that cationic exchange and electrostatic interaction were the main heavy metal ions adsorption mechanisms. These results demonstrate that CE-PAANa graft copolymer sorbents from cellulose-rich SCB can potentially be used for the removal of heavy metal ions.

Fabrication of reduced graphene oxide-doped carbon aerogels from water hyacinth for removal of methylene blue in water and energy storage

The development of industries has caused severe impacts on the environment and increased the demand of using energy. In this work, reduced graphene oxide-doped water hyacinth carbon aerogels (rGO/WHCA) were synthesized by cross-linking cellulose with poly(vinyl alcohol) as a binder and addition of graphene oxide (GO) as rGO precursors, followed by freeze-drying and pyrolysis techniques. The obtained materials were studied for adsorption of methylene blue (MB) in water and applied as electrodes for the supercapacitor. The impact of GO content on the characteristics, adsorption performance, and electrochemical properties of the rGO/WHCA were investigated. Besides, the concurrent effects of the adsorption time, and MB concentration on the adsorption capacity were evaluated via the response surface methodology according to the Box–Behnken model. The obtained rGO/WHCA materials exhibited ultralow density, high porosity, and an abundance of meso- and micropores structures. Especially, rGO/WHCA materials showed a great ability for removing MB in water with the highest adsorption capacity up to 95.03 mg/g after 420 min with the initial MB concentration of 150 ppm at pH 9 and performed the electrical double-layer capacitors (EDLCs) in a three-electrode system with an outstanding specific capacitance of 272.08 F/g at current density of 0.5 A/g. The obtained results open a potential pathway of using biomass sources, like water hyacinth, for solving environmental issues and the demand for energy storage.

A polydiacetylene-based smart cellulose aerogel functionalized by ZnO/MoS2 heterojunction for simultaneous visual detection and photocatalytic degradation of gaseous VOCs

The integration of visual detection and degradation of volatile organic compounds (VOCs) is greatly desired for addressing ever-growing environmental problems. Herein, a chemically cross-linked cellulose aerogel is explored as substrate material, combing with ZIF-8/MoS2 derived 2D ZnO/MoS2 heterojunction. Then polydiacetylene (PDA) was self-assembled on the aerogel via topochemical polymerization to obtain a smart gas sensing and eliminating hybrid aerogel (PZMCA) with high porosity (>96%). The intrinsic stimulate responsiveness and the flower-like hierarchical structure of PDA contributed to a sensitive and fast color response to gaseous toluene with 10 s. Moreover, by regulating the mass ratio of ZnO and MoS2, the PZMCA presented enhanced photocatalytic ability for toluene (97% of degradation efficiency with 180 min) under solar light irradiation. GC-MS reveals the possible mechanism and pathway of the photocatalytic degradation of toluene. The robust, uniform, versatile and functional aerogels could hopefully provide practical applications in VOCs detection and photocatalytic degradation.

Stimuli-Responsive and Antibacterial Cellulose-Chitosan Hydrogels Containing Polydiacetylene Nanosheets.

Herein, we report a stimuli-responsive hydrogel with inhibitory activity against Escherichia coli prepared by chemical crosslinking of carboxymethyl chitosan (CMCs) and hydroxyethyl cellulose (HEC). The hydrogels were prepared by esterification of chitosan (Cs) with monochloroacetic acid to produce CMCs which were then chemically crosslinked to HEC using citric acid as the crosslinking agent. To impart a stimuli responsiveness property to the hydrogels, polydiacetylene-zinc oxide (PDA-ZnO) nanosheets were synthesized in situ during the crosslinking reaction followed by photopolymerization of the resultant composite. To achieve this, ZnO was anchored on carboxylic groups in 10,12-pentacosadiynoic acid (PCDA) layers to restrict the movement of the alkyl portion of PCDA during crosslinking CMCs and HEC hydrogels. This was followed by irradiating the composite with UV radiation to photopolymerize the PCDA to PDA within the hydrogel matrix so as to impart thermal and pH responsiveness to the hydrogel. From the results obtained, the prepared hydrogel had a pH-dependent swelling capacity as it absorbed more water in acidic media as compared to basic media. The incorporation of PDA-ZnO resulted in a thermochromic composite responsive to pH evidenced by a visible colour transition from pale purple to pale pink. Upon swelling, PDA-ZnO-CMCs-HEC hydrogels had significant inhibitory activity against E. coli attributed to the slow release of the ZnO nanoparticles as compared to CMCs-HEC hydrogels. In conclusion, the developed hydrogel was found to have stimuli-responsive properties and inhibitory activity against E. coli attributed to zinc nanoparticles.

Rational Design of Robust and Universal Aqueous Binders to Enable Highly Stable Cyclability of High‐Capacity Conversion and Alloy‐Type Anodes

The development of high‐performance binders is a simple but effective approach to address the rapid capacity decay of high‐capacity anodes caused by large volume change upon lithiation/delithiation. Herein, we demonstrate a unique organic/inorganic hybrid binder system that enables an efficient in situ crosslinking of aqueous binders (e.g., sodium alginate (SA) and carboxymethyl cellulose (CMC)) by reacting with an inorganic crosslinker (sodium metaborate hydrate (SMH)) upon vacuum drying. The resultant 3D interconnected networks endow the binders with strong adhesion and outstanding self‐healing capability, which effectively improve the electrode integrity by preventing fracturing and exfoliation during cycling and facilitate Li+ ion transfer. SiO anodes fabricated from the commercial microsized powders with the SA/0.2SMH binder maintain 1470 mAh g−1 of specific capacity at 100 mA g−1 after 200 cycles, which is 5 times higher than that fabricated with SA binder alone (293 mAh g−1). Nearly, no capacity loss was observed over 500 cycles when limiting discharge capacity at 1500 mAh g−1. The new binders also dramatically improved the performance of Fe2O3, Fe3O4, NiO, and Si electrodes, indicating the excellent applicability. This finding represents a novel strategy in developing high‐performance aqueous binders and improves the prospect of using high‐capacity anode materials in Li‐ion batteries.

One-pot cellulose etherification and self-crosslinking via a mild hydroxyl–yne click reaction in a homogeneous system

The one-pot etherification and crosslinking of cellulose were successfully achieved by a hydroxyl–yne click reaction in a homogeneous system at room temperature.