Cellulose Derivatives Research Articles

The influence of dibutyl sebacate on the sorption properties of a composite superabsorbent based on chitosan

Composite superabsorbents, combining both acrylate and biodegradable units, are more environmentally friendly products compared to fully synthetic analogues, however, their equilibrium degree of swelling Qe, usually, lower than the latter. Therefore, the search for new approaches to increase this parameter is an urgent task of modern chemistry. A promising way to solve this problem seems to be the use of plasticizers - low-molecular compounds that increase the segmental and molecular mobility of macromolecules. The purpose of this study was investigation of the effect of the presence of dibutyl sebacate on the sorption properties of composite superabsorbents containing chitosan. Dibutyl sebacate is known as a plasticizer for many industrially important polymers, including cellulose derivatives, and is also less toxic than commonly used phthalates. Superabsorbents based on acrylic acid and acrylamide containing 10 wt.% chitosan with different molecular weights: 20, 200, and 600 kDa were obtained by radical precipitation polymerization with substance initiation. The structure of the resulting superabsorbents was confirmed by FTIR spectroscopy, and the morphology of their surfaces was studied by scanning electron microscopy. With an increase in the molecular weight of the polysaccharide used, a decrease in the equilibrium degree of swelling of the resulting composite superabsorbent in distilled water was observed. In the case of swelling in a 0.15 M NaCl solution, a sharp decrease in Qe values occurred. The presence of dibutyl sebacate increased the equilibrium degree of swelling in distilled water of superabsorbents obtained based on chitosan with molecular weights of 200 and 600 kDa. The increase in Qe values correlated with the molecular weight of the polysaccharide: the higher it was, the more pronounced was the effect of the presence of dibutyl sebacate. A study of the swelling kinetics of superabsorbents showed that, regardless of the presence of dibutyl sebacate, the process is two-stage: a stage of fast and slow water sorption was observed. Using mathematical kinetic models, it was shown that swelling was controlled by chemisorption, and at the slow stage of swelling, the diffusion of water molecules inside the superabsorbent phase played a significant role. Thus, the use of dibutyl sebacate is a promising approach to increasing the equilibrium degree of swelling of composite superabsorbents based on chitosan with a molecular weight of more than 200 kDa.

Evaluation of synthesized new cellulose derivatives to make diodes and investigation of electrical and photoelectrical characteristics of these diodes

Firstly, two new cellulose derivatives (CelB33′44′TD and Cel44′OA) were synthesized, which were confirmed by FTIR and 13C CP-MAS NMR spectra. These derivatives were then used in the construction of new diodes (Au/CelB33′44′TD/p-Si and Au/Cel44′OA/p-Si). Later, the atomic force microscope (AFM) images of the interface layers were taken, and the current–voltage (I–V) graphs of the diodes were determined both in the dark and under different illumination intensities (DIIs). Using the Bethe's thermionic emission (TE) theory the ideality factors and barrier heights of the diodes, using the Cheung & Cheung functions the ideality factors, series resistances and barrier heights of the diodes, and using the Norde function the barrier heights and series resistances of the diodes were calculated. Finally, the capacitance–voltage (C–V) and conductance–voltage (G–V) graphs of the diodes at different frequencies (DFs) were examined and some frequency-dependent electrical parameters of the diodes were calculated using the 1/C2–V plots.

Cellulose Nanocrystals As a Key in Wearable Sensors

In recent years, the development of cellulose-based inks for 3D printing has received significant interest due to numerous cellulose and its derivatives properties [1], [2]. Carboxymethyl cellulose (CMC) is an anionic water-soluble cellulose derivative widely used as superabsorbent hydrogels [3]. Another cellulose derivative is cellulose nanocrystal (CNC), a rod-like nanoparticle that can be applied for the mechanical strengthening of hydrogels and also presents potential use in several applications in the biomedical field [2], [4]. Based on this, we have proposed to investigate if CMC and CNC mixtures result in cellulose-based nanocomposite gels suitable for extrusion printing of wearable sensors. Interactions between CNC and CMC resulted in physical gels, where rheological properties and extrusion printing parameters' effects were studied. A Modular Compact Rheometer (Anton Paar MCR-102, Austria) with a plate-plate geometry (50 mm diameter and 1 mm gap) at 25 °C was used to perform rheological measurements. Extrusion printing was performed on the customized 3DCloner Lab printer using a 22G nozzle tip of 25 mm in length and a diameter of 0.70 mm (Injex, Brazil). Gels presented shear-thinning, solid-like viscoelastic behavior, viscosity recovery, and continuous filaments obtained during printing. Moreover, the alignment of rod-like CNC during the printing process can be a key to improving properties. Tests with different print and extrusion speeds evidenced the influence of the wearable sensor's geometry and mechanical properties. Moreover, the low cytotoxicity of CMC/CNC crosslinked hydrogels was confirmed through an MTT assay of fibroblasts. Further testing is being conducted to evaluate the self-healing and conductive properties of the sensors by external stimuli. Moreover, low cytotoxicity to CMC/CNC crosslinked hydrogels was confirmed through an MTT assay of fibroblasts. External stimuli are being applied to evaluate the self-healing and conductive of the sensor printed.

(Invited) Progress in Polymer Electrolytes for Li° Electrode

The incentives for the use of lithium metal negative electrode are easily justified considering the gain in energy density. Polymer electrolytes disclosed almost fifty years ago are still considered as an option for the most thought-for all solid-state systems. In fact, the only solid-state batteries commercialised are those from Blue Solutions® powering busses in Europe, using a Li° negative, a PEO [poly(ethylene oxide)] matrix with a LiTFSI solute and an LiFePO4 cathode materials and operating at 70°C. 1500 -2000 cycles are routinely obtained. The main drawbacks of PEO, which is stable to lithium metal is a low conductivity at room temperature (10-5 - 10-6 Ohm-1.cm-1 at 25°C) while it reaches easily 10-3 - 10-4 Ohm-1.cm-1 at 70°C. The other impedimenta of PEO is the relatively low transference/transport number of the Li+ cation (T+ ≈ 0.2), resulting in the formation of a salt concentration gradient in the electrolyte upon operation, with concomitant polarisation and the triggering of dendrites when the Sand time is reached, shortening the cycle life-time. Other polymer matrices like poly(ε-caprolactone) PCL and poly(propylene carbonate) PPC show slightly better conductivity and higher transference number (T+ ≈ 0.5), but are not stable in contact with lithium metal.Our strategy to increase the conductivity at lower temperature consisted in modifying the polymer architecture, from linear (PEO) to comb polymer in which medium length PEG segments (Mw 1000 - 2000) are attached to the main backbone via a flexible non-solvating tether (PPO). This optimises the speed of re-orientation of the solvating units, speed needed to favour the ionic motion. With these polymers and delocalised salts like LiTFSI or LiFSI, conductivities close to 10-4 Ohm-1.cm-1 at 25°C are obtained though with the same transference number as PEO.In order to improve the selectivity of the cation transport in PEs, it is necessary to immobilise the negative charges of the salt by attaching them to a polymer or nano-particles. The other option consists in modifying the salt architecture to slow down the diffusion/migration of the anions by increasing the interactions of the anions with themselves or with the polymer backbone.We have found that, starting for a simple cellulose derivative, the action of FSO2N=C=O results in the attachment of anions to the backbone and that the poly(salts) are now able to form an alloy with PEO or other poly(ethers), with excellent mechanical properties imparted by the rigid cellulose matrix, yet giving Li-only conductivities allowing battery operation. Alternatively, SiO2 or Al2O3 nano-particles can be grafted with delocalised anionic moieties, which result, when dispersed into PEO, in conducting composites with again excellent electrochemical and mechanical properties.Modification of the well-known anion TFSI to increase its interactions and slow it down have been undertaken: either hydrogen bonds, dipole interactions, chain entanglement, or π - π interactions have been introduced in the RSO2N(-)SO2CF3 anion with R equal respectively CF2H—, (CH3)2N—, (CH3OC2H4)2N—, C6H5—. In all cases, higher T+ were obtained as compared with TFSI-, though the total conductivity was lower, but resulting still in σLi+ that translates into better lithium plating efficiencies as seen in the classical Li°/PE/Li° cycling tests and in batteries lifecycle.A final drawback of PEO is its inability to withstand voltages above 3.9 V vs. Li+:Li° while PPC for instance, stable to 4.5V, does decompose rapidly on the negative Li°. The obvious idea to combine a PEO based anolyte and a PPC catholyte stumbles on the consideration that PEO is far more solvating than PPC and deplete totally the polyester compartment, with no conductivity remaining. We solved this problem with the use of an immobilised polyanion in both the anolyte and catholyte, resulting in the stable operation of a Li°/NMC622 battery.All these research results will be discussed in details.

Biofabrication of Cellulose-based Hydrogels for Advanced Wound Healing: A Special Emphasis on 3D Bioprinting.

Even with the current advancements in wound management, addressing most skin injuries and wounds continues to pose a significant obstacle for the healthcare industry. As a result, researchers are now focusing on creating innovative materials utilizing cellulose and its derivatives. Cellulose, the most abundant biopolymer in nature, has unique properties that make it a promising material for wound healing, such as biocompatibility, tunable physiochemical characteristics, accessibility, and low cost. 3D bioprinting technology has enabled the production of cellulose-based wound dressings with complex structures that mimic the extracellular matrix. The inclusion of bioactive molecules such as growth factors offers the ability to aid in promoting wound healing, while cellulose creates an ideal environment for controlled release of these biomolecules and moisture retention. The use of 3D bioprinted cellulose-based wound dressings has potential benefits for managing chronic wounds, burns, and painful wounds by promoting wound healing and reducing the risk of infection. This review provides an up-to-date summary of cellulose-based dressings manufactured by 3D bioprinting techniques by looking into wound healing biology, biofabrication methods, cellulose derivatives, and the existing cellulose bioinks targeted toward wound healing.

Photocrosslinkable Cellulose Derivatives for the Manufacturing of All-Cellulose-Based Architectures.

Replacing petroleum-based polymers with biopolymers such as polysaccharides is essential for protecting our environment by saving fossil resources. A research field that can benefit from the application of more sustainable and renewable materials is photochemistry. Therefore, cellulose-based photoresists that could be photocrosslinked via UV irradiation (λ = 254 nm and λ = 365 nm) were developed. These biogenic polymers enable the manufacturing of sustainable coatings, even with imprinted microstructures, and cellulose-based bulk materials. Thus, herein, cellulose was functionalized with organic compounds containing carbon double bonds to introduce photocrosslinkable side groups directly onto the cellulose backbone. Therefore, unsaturated anhydrides such as methacrylic acid anhydride and unsaturated and polyunsaturated carboxylic acids such as linoleic acid were utilized. Additionally, these cellulose derivatives were modified with acetate or tosylate groups to generate cellulose-based polymers, which are soluble in organic solvents, making them suitable for multiple processing methods, such as casting, printing and coating. The photocurable resist was basically composed of the UV-crosslinkable biopolymer, an appropriate solvent and, if necessary, a photoinitiator. Moreover, these bio-based photoresists were UV-crosslinkable in the liquid and solid states after the removal of the solvent. Further, the manufactured cellulose-based architectures, even the bulk structures, could be entirely regenerated into pure cellulose devices via a sodium methoxide treatment.

Organic acid fractionation of hardwoods planted in social forestry

Abstract Trema orientalis and Trewia nudiflora are the fastest rotation trees (3–4 years’ rotation) in Bangladesh, and experimentally planted in social forestry in Gazipur district. Biorefinery is the most cited topic in research recent era in order to established circular bioeconomy. In established a biorefinery initiative, both species were fractionated into pulp, lignin and hemicellulose by formic acid (FA) treatment at atmospheric conditions. After alkaline peroxide bleaching of FA treated pulp, the yield was 47.0 % and 41.0 % with α-cellulose of 82.39 % and 81.61 %, and residual pentosan content of 9.26 % and 11.13 % for T. orientalis and T. nudiflora, respectively. The brightness of the pulps was 84.5 % and 85.0 %. Cold alkali extraction of the bleached pulp increased α-cellulose to 92.36 % and 91.29 % which was suitable for cellulose derivatives. Lignin was separated from the spent liquor by adding water. The FA lignin from hardwood replaced 20 % phenol in phenol-formaldehyde resin preparation without sacrifice of shear strength. The lignin separated FA liquor contains mainly pentose sugars, which was subsequently converted to furfural with a yield of 41.39 % and 41.72 % at 170 °C using 0.1 % H2SO4 catalyst from T. orientalis and T. nudiflora, respectively.

Jute Stick-Derived Cellulose-Based Hydrogel: Synthesis, Characterization, and Methylene Blue Removal from Aqueous Solution.

In this work, microcrystalline cellulose (MCC) was isolated from jute sticks and sodium carboxymethyl cellulose (Na-CMC) was synthesized from the isolated MCC. Na-CMC is an anionic derivative of microcrystalline cellulose. The microcrystalline cellulose-based hydrogel (MCCH) and Na-CMC-based hydrogel (Na-CMCH) were prepared by using epichlorohydrin (ECH) as a crosslinker by a chemical crosslinking method. The isolated MCC, synthesized Na-CMC, and corresponding hydrogels were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electronic microscopy (SEM), and energy dispersive spectroscopy (EDS) for functional groups, crystallinity, surface morphology, and composite elemental composition, respectively. Pseudo-first-order, pseudo-second-order, and Elovich models were used to investigate the adsorption kinetics. The pseudo-second-order one is favorable for both hydrogels. Freundlich, Langmuir, and Temkin adsorption isotherm models were investigated. MCCH follows the Freundlich model (R2 = 0.9967), and Na-CMCH follows the Langmuir isotherm model (R2 = 0.9974). The methylene blue (MB) dye adsorption capacities of ionic (Na-CMCH) and nonionic (MCCH) hydrogels in different contact times (up to 600 min), initial concentrations (10-50 ppm), and temperatures (298-318 K) were investigated and compared. The maximum adsorption capacity of MCCH and Na-CMCH was 23.73 and 196.46 mg/g, respectively, and the removal efficiency of MB was determined to be 26.93% for MCCH and 58.73% for Na-CMCH. The Na-CMCH efficiently removed the MB from aqueous solutions as well as spiked industrial wastewater. The Na-CMCH also remarkably efficiently reduced priority metal ions from an industrial effluent. An effort has been made to utilize inexpensive, readily available, and environmentally friendly waste materials (jute sticks) to synthesize valuable adsorbent materials.

Combination of polylactide with cellulose for biomedical applications: a recent overview

AbstractThis review summarizes the use of cellulose and polylactide for medical applications with particular emphasis on modern dressings. Although classic cotton and viscose dressings are still available and popular, the usefulness of new forms of cellulose (Cel) and its derivatives opens new wound treatment options. Therefore, trends in functionalizing traditional cellulose dressings, including products made of bacterial cellulose, and dressings from cellulose derivatives, are discussed. Polylactide (PLA), in turn, is a biodegradable and biocompatible polyester that fulfills plenty of tasks in many medical fields, from surgery to modern diagnostic methods. However, polylactide dressings can still be advantageous to the market. Thus, the next part of the article contains a recent update of available knowledge about PLA and its applications in regenerative medicine and drug-delivery systems. The last part is devoted to the possibilities of combining both materials in dressings and related problems and benefits. Methods for compatibilization with the surface of both polymers and new techniques for producing Cel/PLA composite materials are also described.

Evaluation of inherent properties of the carboxymethyl cellulose (CMC) for potential application in tissue engineering focusing on bone regeneration

AbstractBiomaterials are essential in medicine because these biological macromolecules have appropriately replaced classical tissue grafting techniques for their valuable features. Bone tissue engineering has persistently developed since “tissue engineering” was suggested. Carboxymethyl cellulose (CMC) is the first FDA‐approved water‐soluble derivative of cellulose that could be targeted for desired bone tissue graft. Numerous studies on CMC as a component created for bone tissue have recently been published. Because of its carboxylate groups, CMC is hydrophilic. CMC can crosslink with varied materials, such as synthetic and natural polymers, enabling innovative bone structure biomaterials. These carboxylate groups are responsible for in situ gelations and bio‐adhesion characteristics. In this review, the current progress and inherent characteristics of CMC‐based bone scaffold materials are discussed.

Saccharide branched cellulose with controllable molecular structure and excellent water retention ability

In this work, saccharide branched cellulose (saccharide b-Cel) was synthesized by combining reducing saccharides with cellulose molecules using Ugi four-component reaction (Ugi-4CR). First, the carboxyl groups required for Ugi-4CR are obtained by carboxymethylating cellulose molecules. Then, saccharide b-Cel with a controlled molecular structure is formed when the terminal aldehyde group of reducing saccharides combines with the carboxyl group and auxiliary functional group. The types of saccharides, the degree of substitution of carboxymethyl groups, and the degree of branching all affect the molecular structure of saccharide b-Cel. Through molecular structural regulation, the relationship between the branching structure and water retention ability of saccharide b-Cel was examined in detail. This work not only provides new insights into the synthesis of cellulose derivatives, but it also provides a template for the synthesis of other biomass derivatives.

Scientific approaches to the creation of technology structured milk desserts with a combined composition of raw materials

One of the promising areas of the dairy industry is the production of combined products. Its essence consists in the directed regulation of the constituent components of products in order to improve their composition and properties. Today, dairy desserts are one of the most popular products on the domestic market. In order to expand the range of dairy desserts, improve their structure and quality, increase the nutritional value and reduce the calorie content, it is rational to use non-traditional raw materials that contain the necessary functional ingredients. To obtain dairy desserts with a certain structure, it is necessary to use the appropriate components of animal and plant origin. For example, milk powder, milk and whey concentrates, condensed milk products, hydrocolloids (food fibers, starch, gelatin, cellulose derivatives, gums, etc.). Justification of the use of the above-mentioned components during the development of the technology of dairy desserts with a combined composition of raw materials is an actual direction of scientific research. The purpose of the work was to develop a scientifically based model for combining protein and carbohydrate components in the composition of dairy desserts with gel-like and complex dispersed structures and to create pudding and cream technology. The article presents a developed model of combining protein and carbohydrate components in structured dairy desserts. Based on the model of combining carbohydrate and protein components in dairy desserts, we have developed cream and pudding technologies based on buttermilk or retentate. In order to obtain dairy desserts with aggregative stability, it is necessary to carry out thermomechanical processing at a temperature of 80–85 °C with constant mixing and agitator revolutions of 2800 rpm, followed by packaging without cooling. The organoleptic and physico-chemical parameters of the produced samples of dairy desserts were studied. It was established that dairy desserts have the maximum moisture retention capacity – 100%, their sugar and fat content is 43–52% and 33–47% lower, respectively, and the protein content is 3–5 times higher than in traditional types of desserts. It has been proven that on the basis of the developed and scientifically based model of combining protein and carbohydrate components, low-calorie structured dairy desserts with high protein content, low fat and sugar content and appropriate quality indicators were obtained. Key words: dairy desserts, creams, puddings, combined composition of raw materials, technology, structure, secondary dairy raw materials, whey proteins, hydrocolloids.

Towards Tailored Dialdehyde Cellulose Derivatives: A Strategy for Tuning the Glass Transition Temperature.

The derivatization of dialdehyde cellulose (DAC) has received increasing attention in the development of sustainable thermoplastics. In this study, a series of dialcohol celluloses were generated by borohydride reduction, which exhibited glass transition temperature (Tg ) values ranging from 23 to 109 °C, depending on the initial degree of oxidation (DO) of the DAC intermediate. However, the DAC derivatives did not exhibit thermoplastic behavior when the DO of the modified DAC was below 26 %. The influence of introduced side chains was highlighted by comparing DAC-based thermoplastic materials obtained by either oximation or borohydride reduction. Our results provide insights into the generation of DAC-based thermoplastics and highlight a strategy for tailoring the Tg by adjusting the DO during the periodate oxidation step and selecting appropriate substituents in subsequent modifications.

The Role of Binders for Water-Based Anode Dispersions in Inkjet Printing

Binders play a pivotal role in the production and the operation of lithium-ion batteries. They influence a number of key dispersion characteristics and battery parameters. In the light of growing interest in additive manufacturing technologies, binders were found to decisively govern the processability due to the induced complex non-Newtonian behavior. This paper examines the relevance of various binder derivatives for aqueous graphite dispersions that can be employed in inkjet printing. Two different carboxymethyl cellulose (CMC) derivatives with strongly deviating molecular weights were employed. The impact of the inherent polymer characteristics on the processability and the electrode characteristics were explored. Therefore, miscellaneous studies were carried out at the dispersion, the electrode, and the cell levels. The results revealed that the CMC with the lower molecular weight affected most of the studied characteristics more favorably than the counterpart with a higher molecular weight. In particular, the processability, encompassing drop formation and drop deposition, the cohesion behavior, and the electrochemical characteristics, were positively impacted by the low-molecular-weight CMC. The adhesion behavior was enhanced using the high-molecular-weight CMC. This demonstrates that the selection of a suitable binder derivative merits close attention.

Applications of biodegradable carboxymethyl cellulose-based composites

Carboxymethyl cellulose (CMC), a cellulose derivative, is a versatile biopolymer with promising applications in different areas. The carboxymethyl cellulose-based composites possess excellent properties, namely easy availability, easy synthesis, high viscosity, biocompatibility, biodegradability, water-solubility, easy structural modifications, tissue resemblance, low cost, and non-toxicity, have attracted a great deal of attention in recent years. It is widely employed in a wide range of biological and pharmacological applications. This review paper describes applications of CMC-based in different applications and proposes them as a green alternative to conventional polymers for future sustainable development.

Research by choice of excipients ingredients of the gel for the therapy of radiation lesions of the skin based on rheological studies

The aim of this work is to conduct a research analysis of changes in the structural and mechanical properties of the gel from the addition of active substances and surfactants.
 Materials and methods. In the presented work, model samples of the gel with active substances were studied: freshly obtained stonecrop juice, sea buckthorn oil, rosehip oil, St. John's wort oil and quercetin. As substances for the manufacture of bases hydrocolloids of cellulose derivatives were used: sodium carboxymethylcellulose (NaCMC) and hydroxyethylcellulose (HEC) with a surfactant Lanette SX.
 A study of the rheological properties of the samples was performed using a rheoviscometer Rheolab QC (Anton Paar, Austria) using a system of coaxial cylinders C-CC27 / SS. The Rheolab QC rheometer is equipped with RheoPlus software, which allows you to set the necessary experimental conditions (shear rate gradient range, number of measuring points and measurement time of one point).
 Results. The rheological properties of model samples of NaCMC and HEC gels, depending on the used concentration, were studied. With increasing concentrations of both NaCMC and HEC thixotropy of dispersed systems decreases. The change of structural and mechanical parameters of hydrogels from the addition of active ingredients and surfactant is analyzed, and established that adding them into the hydrogels increases the structural and mechanical parameters of model samples.
 A study of gels with a constant concentration of sodium carboxymethylcellulose and hydroxyethylcellulose and different content of surfactant Lanette SX established that as the surfactant concentration increases, the area of the hysteresis loop and the resistance of the dispersed system to the applied mechanical fracture increase.
 Conclusions. According to the results of the obtained structural and mechanical parameters and rheograms of the studied model samples of gels, it is rational to use in further studies of sodium carboxymethyl-cellulose (1.5 %) and hydroxyethylcellulose (1.25 %) stabilized Lannete SX in concentrations of 4-5 % and 3-5 % respectively

A new ternary nanocomposites-based cellulose derivatives-CuFe2O4-zeolite with ultra-high adsorption capacity for Brilliant Green dye treatment and removal from the aquatic environment

In contemporary times, there has been a notable emphasis on the advancement of adsorbents with high efficiency for the purpose of extracting organic dyes from wastewater. Therefore, a suggested method involves improving the surfaces of adsorbents by changing polymers in order to make them better at absorbing substances. The goal of this study was to create a very effective nanocomposite (NCs) by combining CuFe2O4 nanoparticles (CuF NPs) and zeolite (ZSM-5) with different types of cellulose, such as cellulose (CE), cellulose acetate (CEA), and carboxymethyl cellulose (CMC), in order to remove Brilliant Green (B.G.), a cationic dye, from water solutions. We investigated the influence of several factors on the efficacy of dye removal by NCs. These factors included the kind of cellulose derivative used, adsorbent dose, solution temperature, pH, and contact duration. The results of the prepared ternary ZSM-5/CuF/CE, ZSM-5/CuF/CEA, and ZSM-5/CuF/CMC NCs show that among the fabricated NCs, the ZSM-5/CuF/CE NCs have the highest adsorption capacity (9.66 mg/g). This result highlights the promising capability of these NCs in effectively removing B.G. dye. The results obtained from the studies on dye removal provided evidence that the adsorption process occurred spontaneously and exothermic, as supported by both thermodynamic and kinetic criteria. The values of the R2 correlation coefficient for ternary ZSM-5/CuF/CE and ZSM-5/CuF/CEA NCs for B.G. dye were 0.993 and 0.995, respectively.

Sodium Alginate- and Cationic Cellulose-Functionalized Polycaprolactone Nanofibers for In Vitro and Antibacterial Applications.

The use of polyelectrolytes is emerging as a fascinating strategy for the functionalization of biomedical membranes, due to their ability to enhance biological responses using the interaction effect of charged groups on multiple interface properties. Herein, two different polyelectrolytes were used to improve the antibacterial properties of polycaprolactone (PCL) nanofibers fabricated via electrospinning. First, a new cationic cellulose derivative, cellulose-bearing imidazolium tosylate (CIMD), was prepared via the nucleophilic substitution of the tosyl group using 1-methylimidazole, as confirmed by NMR analyses, and loaded into the PCL nanofibers. Secondly, sodium alginate (SA) was used to uniformly coat the fibers' surface via self-assembly, as remarked through SEM-EDX analyses. Polyelectrolyte interactions between the CIMD and the SA, initially detected using a FTIR analysis, were confirmed via Z potential measurements: the formation of a CMID/SA complex promoted a substantial charge neutralization of the fibers' surfaces with effects on the physical properties of the membrane in terms of water adsorption and in vitro degradation. Moreover, the presence of SA contributed to the in vitro response of human mesenchymal stem cells (hMSCs), as confirmed by a significant increase in the cells' viability after 7 days in the case of the PCL/CMID/SA complex with respect to the PCL and PCL/CMID membranes. Contrariwise, SA did not nullify the antibacterial effect of CMID, as confirmed by the comparable resistance exhibited by S. mutans, S. aureus, and E. coli to the PCL/CIMD and PCL/CIMD/SA membranes. All the reported results corroborate the idea that the CIMD/SA functionalization of PCL nanofibers has a great potential for the fabrication of efficient antimicrobial membranes for wound healing.

Kinetic Modeling of Cornstalk Cellulose Hydrolysis in Supercritical Water: A Comparative Study of the Effects of Temperature and Residence Time on Derivative Production

Kinetic modeling is essential in understanding and controlling the process of cellulose hydrolysis for producing value-added cellulose derivatives. This study aims to adopt a set of dominate kinetic ordinary differential equations of cornstalk cellulose hydrolysis in supercritical water for mechanism-based prediction of the production of cellulose, glucose, fructose, glyceraldehyde, erythrose, 5-hydroxymethyl furfural, glycolaldehyde, threose, aldose, and other cellulose derivatives from cornstalks under processing conditions with a pressure of 89 MPa and a temperature of 378 °C, as considered in a recent experimental study in the literature. The yield rates of several cellulose derivatives, e.g., glucose, fructose, 5-HMF, and erythrose as predicted by the present model, are close to those of experimental measurements. The model is further used to predict the yield rates of a few new cellulose derivatives, e.g., glycolaldehyde, threose, and aldose, that are potentially generated in cornstalk cellulose hydrolysis in supercritical water. The present model and computational simulations can be utilized as a rational tool to predict, control, and optimize the derivative yields in cellulose hydrolysis in supercritical water via tuning the process parameters, and, therefore, are useful for the optimal production of targeted bio-based fuels and chemicals from cornstalks and other agricultural and municipal wastes.

Compatibility–structural color property relationship of binary blends of acetylated hydroxypropyl celluloses with different degrees of acetylation

AbstractPolymer blends containing liquid crystalline cellulose derivatives potentially enable the fabrication of optical functional materials because of their unique optical properties, that is, structural color and circular dichroism. However, studies on the effect of the compatibility of the components on the optical properties of such blends are scarce, even though component compatibility is a crucial factor for the physical properties of the polymer blends. In this study, we investigated the effect of the component compatibility on the structural color property of binary blends of acetylated hydroxypropyl celluloses (AHPCs) with different degrees of acetylation (DSAc). The spectroscopic analyses of the AHPC blends revealed that the structural color of blends with a small DSAc gap between AHPC components systematically changed with the blend composition, whereas the color of blends with a large DSAc gap was independent of the composition. Compatibility tests via spin–lattice relaxation time measurements using solid‐state nuclear magnetic resonance indicated that the different composition dependence of the color was attributed to the compatibility of the components, which varied according to the DSAc gap.