Cellulosic Materials Research Articles

Synthesis of Amorphous Cellulose Derivatives via Michael Addition to Hydroxyalkyl Acrylates for Thermoplastic Film Applications

The aim of this study is to prepare new cellulose derivatives that show good feasibility and processability. Accordingly, in this study, we demonstrate Michael addition to hydroxyalkyl acrylates, that is, 2-hydroxyethyl and 4-hydroxybutyl acrylates (HEA and HBA, respectively), to synthesize amorphous cellulose derivatives under alkaline conditions. The reactions were carried out in the presence of LiOH in ionic liquid (1-butyl-2,3-dimethylimidazolium chloride)/N,N-dimethylformamide (DMF) solvents at room temperature or 50 °C for 1 h. The Fourier transform infrared and 1H nuclear magnetic resonance (NMR) measurements of the products supported the progress of Michael addition; however, the degrees of substitution (DS) were not high (0.3–0.6 for HEA and 0.6 for HBA). The powder X-ray diffraction analysis of the products indicated their amorphous nature. The cellulosic Michael adduct from HEA with DS = 0.6 was swollen with high polar organic liquids, such as DMF. In addition to swelling with these liquids, the cellulosic Michael adduct from HBA was soluble in dimethyl sulfoxide (DMSO), leading to its 1H NMR analysis in DMSO-d6. This adduct was found to form a cast film with flexible properties from its DMSO solutions. Furthermore, films containing an ionic liquid, 1-butyl-3-methylimidazolium chloride, showed thermoplasticity. The Michael addition approach to hydroxyalkyl acrylates is quite effective to totally reduce crystallinity, leading to good feasibility and processability in cellulosic materials, even with low DS. In addition, the present thermoplastic films will be applied in practical, bio-based, and eco-friendly fields.

Magnetized cellulosic material from Cannabis biomass as a green adsorbent: Effective removal of paracetamol from wastewater

Magnetized cellulosic material from Cannabis biomass as a green adsorbent: Effective removal of paracetamol from wastewater

Construction and 3D Printing of Multiscale Silk Fiber‐Cellulose Composite Networks Based on Ionic Liquids

AbstractMicroscopic defects in the amorphous regions of natural cellulose affect the mechanical properties of their materials. After dissolution and regeneration, cellulose's mechanical properties are still insufficient for application in advanced materials. Conventional compounding and crosslinking techniques with toxic crosslinking agents are not only cumbersome, but also have limited performance enhancement in cellulose materials Therefore, much attention has been paid to designing and developing more straightforward and efficient cellulose reinforcement technologies. Herein, an in situ multiscalarization strategy is used to form multiscale silk fiber‐cellulose composites (MS‐C) by the gradual nanosizing of silk fibers (SF) under heating in a 1‐butyl‐3‐methylimidazolium chloride solution of cellulose (Cel‐BmimCl). MS‐C are constructed from micro and nano SF, fibroin chains, and cellulose molecules into a multidimensional network. Due to its advantage of multiscale structure, MS‐C has excellent mechanical properties, the tensile strength and Young's modulus, which are 123.06% and 91.68% higher than that of pure regenerated cellulose after 5h heating treatment. Besides, MS‐C has good biocompatibility and can be molded or 3D printed with direct ink writing, showing broad application prospects in medical, bioengineering, and other fields. This multiscale enhancement strategy can also be extended to the research and application of biopolymers such as natural polysaccharides or proteins.

Choice of an environmentally friendly method of producing cellulose from flax biomass (<i>Linum usitatissimum linaceae</i>) grown in different regions of the Volga region

The experimental assessment of prospects of receiving cellulose material on the basis of use of vegetable raw materials – straw of a flax-dolgunetc is carried out. Results of researches showed a possibility of application for extraction of cellulose of the water solutions containing hydrogen peroxide, hydroxide and sodium bisulfite in the conditions of high-temperature influence within 2 hours with receiving the technical cellulose suitable for production of cardboard and packaging materials. For purification of technical cellulose, it was carried out additional processing by solution of hydrogen peroxide and acetic acid in similar parametrical conditions that allowed to receive a target product with high extent of maintenance of the main substance, at insignificant amount of the accompanying impurity. The presented results show a possibility of the solution of questions of environmental safety at the organization of process of receiving cellulose on the basis of renewable vegetable raw materials with use of the chemical reagents which are not containing compounds of sulfur.

Effect of pretreatment and peracetic acid pulping on cellulosic materials converted from spent coffee grounds.

Spent coffee grounds (SCG) are the waste byproducts of coffee brewing. While SCG can be valorized to produce functional biopolymers due to their valuable structural components, the lignocellulosic structure of SCG is resistant to degradation because of the tightly bound lignin. Therefore, a pretreatment step is required before pulping with peracetic acid (PAA), an eco-friendlier alternative to traditional pulping methods, to facilitate the extraction of these desired cellulosic materials. Formic acid:acetic acid:deionized water (FA:AA:W=30:50:20) or 60% (v/v) ethanol pretreatments were applied to SCG to compare the characteristics of the resulting cellulosic materials after PAA pulping. Lignocellulose analysis showed that the lignin content (7.06%) of ethanol pretreated SCG was significantly lower (p<0.05), and the cellulose content (29.52%) was significantly higher (p<0.05) than the untreated SCG (15.50% and 11.50%, respectively), indicating that an adequate amount of lignin was removed to obtain the cellulosic materials after the pretreatment process. Morphological and structural changes in the lignin and hemicellulose were observed in all the pretreated SCG, which further confirmed that these components were degraded with pretreatments and pulping. Ethanol pretreated SCG showed the most optimal results based on the greatest lignin decrease seen from its lignocellulose composition, appearance, and structure. This study exemplified a conversion process to extract cellulosic materials from SCG more efficiently to utilize for cellulose-based products and verify its potential to be valorized as a waste byproduct. PRACTICAL APPLICATION: Coffee companies can provide the spent coffee grounds (SCG) they produce to develop cellulose-based materials to make biodegradable packaging products rather than throwing them out or burning them. Using SCG for producing cellulose-based materials can help promote sustainability and reduce food waste worldwide. SCG can be utilized as an alternative source based on their abundance and desired biopolymeric properties, providing innovative solutions to industries and increasing consumer awareness of this cause.

Green hybrid composites partially reinforced with flax woven fabric and coconut shell waste-based micro-fillers

This research is focused on hybrid green composites using flax woven fabric in which the matrix phase was further reinforced with coconut shell waste-based cellulosic microparticles as fillers. Mesoscale mechanical models were successfully developed to simulate the tensile properties of such hybrid composites based on hybridization of fibers and biobased materials using epoxy resin. S-glass fabrics with plain, twill and biaxial constructions, were used as the outer layers, while plain-woven flax fabric was used as the middle layer. A high level of agreement was observed between the experimental and predicted values. The static tensile tests were followed by cyclic tensile tests, microscopic analysis of fracture surfaces and dynamic mechanical analysis. The influence of the hybrid fabric geometry and combination with biowaste-based micro cellulosic material was observed to significantly influence the tensile properties determined by both experimental and numerical analysis. Dynamic mechanical analysis also validated the quasistatic measurements. A higher storage modulus and loss modulus were registered for the hybrid composites impregnated with a 1 % bio filler-based matrix. The damping factor (tan delta) was lower for the hybrid composites than for the nonhybrid samples and the control samples from the pure matrix. This difference is attributed to the stronger interface between the fibers and the particle-based matrix, which restricts the molecular mobility and increases the stiffness of the composites. Fractographic images were obtained by scanning electron microscopy (SEM) to study the failure modes and mechanisms of the composite samples. The microparticles were uniformly dispersed in the epoxy resin and thus enabled microcracking rather than macrocracks. The failure mainly occurred due to fiber failure, matrix cracking and delamination. Such hybrid composites are useful for exterior and interior components in automotive applications.

High porosity, excellent mechanical strength, interpenetrating network-reinforced double network regenerated cellulose separators for lithium-ion battery

Cellulose material is emerging as a promising alternative to polyolefin separators in lithium-ion batteries (LIBs) due to its wide availability, electrolyte wettability and thermal stability. Based on the non-solvent induced phase separation, dissolving and regenerating the cellulose material by environmentally friendly solvents and non-solvent enables the efficient and pollution-free preparation of porous regenerated cellulose separator (RCS), greatly expanding their application potential in LIBs. However, the mechanical strength of pure RCS still hardly satisfactory, due to the weak intermolecular bonding and loose porous structure. Therefore, this study introduced an acrylic acid/acrylamide (AA/AM) polymer cross-linking system forming an interpenetrating network with the cellulose framework to produce a double network regenerated cellulose separator (DN-RCS) with high mechanical strength and high porosity. At meantime, the special functional group on AA/AM can influence the transport process of Li+ and PF6− in the electrolyte, helping to form a stable interface on the electrolyte/lithium anode surface to reduce the formation of lithium dendrites. The results showed that DN-RCS possessed excellent mechanical strength and porosity compared to RCS. The high ionic conductivity of DN-RCS (1.03 mS cm−1) enabled the assembled cell with excellent cycling stability (90.8 % at 0.5C for 100 cycles) and rate performance (65.2 % at 5C). This work provides a further feasible strategy for the preparation of a high-performance cellulose-based separator.

Mussel-inspired modified regenerated cellulose as tissue adhesive and antibacterial gauze: A promising approach for rapid hemostasis in non-compressible hemorrhage

Uncontrollable hemorrhage leads to high mortality rates; thus, engineering effective hemostatic materials is crucial for rapid hemostasis. Developing hemostatic materials for rapid coagulation, antibacterial activity, and easy removal without compromising clot integrity remains a challenge. Herein, a multifunctional hemostatic gauze was engineered by modifying regenerated cellulose textile through multiple sequential chemical reactions, including carboxymethylation, crosslinking with CaCl2/ZnCl2 solution, oxidation, and polymerization with dopamine. Provided gauze demonstrated remarkable wet-tissue adhesion (890 kPa) that physically sealing the area to prevent blood loss. The engineered gauze exhibits excellent antibacterial activity (against S. aureus and E. coli) and enhanced hemostatic ability (clotting time (20S), attachment of red blood cells (~93 %) and platelets (~80 %)). The complete hemostasis and stable clot formation without secondary bleeding were achieved by synthesized gauze in 20s, 50s, and 100s for the rat and rabbit liver, and rat femoral artery injury models, respectively. That was significantly faster hemostasis (4–14-fold reduction in time) and lower blood loss (3-fold reduction) compared to the commercial hemostatic textiles (p < 0.001). Biochemical, hematological, and pathological examinations revealed no evidence of systemic and local inflammation or toxic effects in the rat organs. The engineered hemostatic gauze exhibits outstanding characteristics of a hemostatic material for clinical applications.

Composites based on cellulose and metal-organic frameworks for dye removal from wastewater

Industrial effluents from enterprises using dyes are among the main production wastes polluting the environment and surface waters. In order to solve this problem, much attention has recently been paid to innovative processes for their removal. The review considers research works over the past 10 years on various biological, chemical and physical methods for dye removal and assesses their effectiveness. The possibility of using cellulose and cellulose-based materials for dye removal from aqueous solutions is shown. The main attention is paid to composites based on cellulose and metal-organic frameworks (Cell-MOF). The main approaches to the creation of Cell-MOF materials and the possibility of regulating their properties are considered. Examples of using Cell-MOF materials for removing dyes from aqueous solutions by adsorption and catalytic methods are given. Prospects and problems of their practical use are discussed.

Multifunctional radiative cooling cellulose fabrics by in situ grown ZnO for personal thermal management

Multifunctional radiative cooling cellulose fabrics by in situ grown ZnO for personal thermal management

Rapid surface acetylation of cellulosic materials at room temperature by immersion method

Regulating the surface hydrophobicity of cellulosic materials via surface acetylation can greatly extend their applications. However, most of the existing surface acetylation methods for cellulosic materials are time-consuming and costly. Herein a simple but practical immersion method for the rapid surface acetylation of cellulose materials was reported, which involved soaking cellulosic materials in alkaline aqueous solution followed by immersed them in vinyl acetate. Results showed that simply wetting the surface of cellulosic materials with aqueous alkaline solutions can satisfy their surface acetylation requirement, and the consumption of esterifying agent can be significantly reduced. The immersion method can rapidly improve the surface properties of the cellulosic materials at room temperature within minutes and which is highly attractive to the surface acetylation of cellulose fibers. The moisture regain of the viscose filament obviously decreased after surface acetylation. When the surface acetylated viscose fiber was used as cigarette filter, the total particulate matter in the filtered cigarette smoke significantly reduced from 11.03 mg/cigarette to 6.03 mg/cigarette. The products are promising alternatives to the existing cigarette filters.

Recent Advance of Sustainable Polymers for Packaging Applications

The extensive application of non-renewable polymers has brought about deep environmental concerns, demonstrating the immediate requirement for new biodegradable and biobased packaging choices. The work offers an in-depth look at a wide array of degradable and biobased polymers like Polylactic Acid (PLA), Polyhydroxyalkanoates (PHA), and Polyvinyl Alcohol (PVOH), as well as starch and cellulose materials, discussing their qualities, uses, and the issues faced in food packaging. These types of green polymers, either in new ways or from renewable sources, offer great advances not only from decomposition into harmless parts but also from the reduction of environmental damage. The essay covers the exploitation side of this material, be it the role of PLA in enzymatic, hydrolytic, or microbial degradations, or the main tactical function of PHA in terms of a water barrier aimed at preserving the quality of stored food. Additionally, the multifunctionality of these substances is represented anew in packaging dairy goods, such as fruits, and vegetables, and specialized applications like edible films or water-soluble bags. The participation of compostable polymers has become increasingly vital in the area of food packaging to meet consumers’ demands and to upgrade the present science technologies aimed at guiding food producers who are looking for more sustainability in their business.

Lost in the Dark: Current Evidence and Knowledge Gaps About Microplastic Pollution in Natural Caves

In this study, a systematic review of the scientific literature was carried out to summarize the emerging evidence on microplastic pollution in natural caves. After the screening of 655 papers on the topic from a combined search on the Web of Knowledge and the Scopus databases, we found only 14 studies reporting quantitative data on microplastics from a total of 27 natural caves. Most of the assessments focused on water and sediment, with very limited investigations concerning the cave biota. Overall, the most common types of particles found in caves were small (&lt;1 mm) fibers (~70–90% of items), transparent or light-colored, mostly made of polyethylene and polyethylene terephthalate. Anthropogenic cellulosic materials, however, represented a non-negligible portion of particles (i.e., ~20–30%). Microplastic concentrations in caves varied between 0.017 and 911 items/L for water and 7.9 and 4777 items/kg for sediment, thus falling within the levels of microplastic pollution found in other terrestrial, freshwater, and marine environments. Levels of microplastic pollution appear largely variable among caves, stressing the need to extend the geographic and environmental ranges of the assessments, which are currently concentrated on Italian caves on land, with very few case studies from other regions of the world and from marine caves. Despite their putative isolation, natural caves have a high vulnerability to microplastic contamination, requiring much more research effort to understand the potential risk that plastics pose to these fragile ecosystems.

Methanol Equilibrium Curves of Power Transformer Oil–Paper Insulation

To eliminate the problem of the aging of cellulose insulation in the manufacturing stage, a new drying method is being developed based on the use of methanol vapors. Previous studies have shown that the complete removal of methanol from the cellulose insulation after the drying process is very difficult. Therefore, it is necessary to check how the remaining methanol after drying affects the properties of both the cellulose materials and mineral oil. To conduct such studies, it is necessary to know the methanol content in oil that can be expected depending on its initial content in the cellulose materials and the temperature of the insulation system. Therefore, the main goal of this work is to develop methanol equilibrium curves for oil–paper insulation. To achieve the assumed goal, three-stage studies were conducted. A gas chromatograph equipped with a flame ionization detector was used in all stages of these studies. The gas partition coefficient between oil and air was determined for a temperature of 70 °C. The key experimental finding was the development of methanol equilibrium curves for oil–paper insulation. Thanks to this achievement, it is possible to estimate the methanol content in cellulose materials and mineral oil depending on the insulation temperature. Such data are necessary, among others, to plan appropriate studies aimed at assessing the impact of methanol content on the dielectric and physicochemical properties of these materials, important from the point of view of the operation of power transformers.

A novel green approach for reactive printing of cotton/cellulosic regenerated blended fabrics using trisodium nitrilotriacetate

Owing to their comfort, handle, and aesthetic characteristics, cotton fabrics will always be the first and primary choice for clothing and apparel. In recent years, regenerated cellulosic fabrics like bamboo, Tencel, and modal fabrics have had many natural advantages. Fabrics based on blending cotton fibres with regenerated cellulosic fibres are considered promising products in textile industry sectors. Use of urea poses ecological problems associated with the high nitrogen content of the printing effluent. Therefore, urea reduction or elimination in reactive dye print pastes is of ecological interest. We report the use of trisodium nitrilotriacetate as a complete substitution of urea and alkali in the conventional reactive printing of cotton/cellulosic regenerated blended fabrics. CI Reactive Black 5 was selected for the present study. Three different print pastes containing urea/alkali, trisodium nitrilotriacetate/alkali and trisodium nitrilotriacetate without alkali were thoroughly investigated. Different factors that may affect the printability of cotton/cellulosic regenerated blended fabrics, such as the concentrations of dye, trisodium nitrilotriacetate, urea, absence or presence of alkali and steaming time in the prints obtained, were evaluated concerning colour strength, dye fixation, dye penetration, levelling, colure, and fastness properties. All printed fabrics using three print pastes obtained excellent to good fastness. The results proved the viability of using TNA as an environmentally friendly approach for urea/alkali-free printing of cellulosics with reactive dyes.

Characterization of MSC Growth, Differentiation, and EV Production in CNF Hydrogels Under Static and Dynamic Cultures in Hypoxic and Normoxic Conditions.

Mesenchymal stem cells (MSCs) hold immense therapeutic potential due to their regenerative and immunomodulatory properties. However, to utilize this potential, it is crucial to optimize their in vitro cultivation conditions. Three-dimensional (3D) culture methods using cell-laden hydrogels aim to mimic the physiological microenvironment in vitro, thus preserving MSC biological functionalities. Cellulosic hydrogels are particularly promising due to their biocompatibility, sustainability, and tunability in terms of chemical, morphological, and mechanical properties. This study investigated the impact of (1) two physical crosslinking scenarios for hydrogels derived from anionic cellulose nanofibers (to-CNF) used to encapsulate adipose-derived MSCs (adMSCs) and (2) physiological culture conditions on the in vitro proliferation, differentiation, and extracellular vesicle (EV) production of these adMSCs. The results revealed that additional Ca2+-mediated crosslinking, intended to complement the self-assembly and gelation of aqueous to-CNF in the adMSC cultivation medium, adversely affected both the mechanical properties of the hydrogel spheres and the growth of the encapsulated cells. However, cultivation under dynamic and hypoxic conditions significantly improved the proliferation and differentiation of the encapsulated adMSCs. Furthermore, it was demonstrated that the adMSCs in the CNF hydrogel spheres exhibited potential for scalable EV production with potent immunosuppressive capacities in a bioreactor system. These findings underscore the importance of physiological culture conditions and the suitability of cellulosic materials for enhancing the therapeutic potential of MSCs. Overall, this study provides valuable insights for optimizing the in vitro cultivation of MSCs for various applications, including tissue engineering, drug testing, and EV-based therapies.

Biotechnology in Food Packaging Using Bacterial Cellulose.

Food packaging, which is typically made of paper/cardboard, glass, metal, and plastic, is essential for protecting and preserving food. However, the impact of conventional food packaging and especially the predominant use of plastics, due to their versatility and low cost, bring serious environmental and health problems such as pollution by micro and nanoplastics. In response to these challenges, biotechnology emerges as a new way for improving packaging by providing biopolymers as sustainable alternatives. In this context, bacterial cellulose (BC), a biodegradable and biocompatible material produced by bacteria, stands out for its mechanical resistance, food preservation capacity, and rapid degradation and is a promising solution for replacing plastics. However, despite its advantages, large-scale application still encounters technical and economic challenges. These include high costs compared to when conventional materials are used, difficulties in standardizing membrane production through microbial methods, and challenges in optimizing cultivation and production processes, so further studies are necessary to ensure food safety and industrial viability. Thus, this review provides an overview of the impacts of conventional packaging. It discusses the development of biodegradable packaging, highlighting BC as a promising biopolymer. Additionally, it explores biotechnological techniques for the development of innovative packaging through structural modifications of BC, as well as ways to optimize its production process. The study also emphasizes the importance of these solutions in promoting a circular economy within the food industry and reducing its environmental impact.

Functionalization of cellulose nanocrystals with a potent antimalarial compound: Synthesis, characterization, and biological studies

Cellulosic materials, such as cellulose nanocrystals (CNCs), are biocompatible, biodegradable and have unique and fascinating biomedical applications. Calxinin (CXN), a potent multistage antimalarial compound was functionalised with CNCs to improve biocompatibility and enhance the bioactivity of the resulting CNC-CXN nano-conjugate. Elemental analysis, powder X-ray, SEM, AFM, Infrared, and solid-state NMR spectroscopic techniques confirmed the composition of novel CNC-CXN nano-conjugate. Next, CNC-CXN nano-conjugate did not exhibit apparent cytotoxic effects on the sensitive Vero E6 cell line up to a concentration of 4.66 μg/μl. The CNC-CXN nano-conjugate was also evaluated for its preliminary efficacy on Plasmodium falciparum (3D7) malaria parasite and showed a 50 % inhibitory concentration value of 0.02 μg/μl. Overall, the selectivity index (SI) of the CNC-CXN nano-conjugate significantly improved to 233, indicating its suitability for further validation studies in animal models.

Synthesis of bioplastics and the effects of additives on the mechanical, thermal and biodegradable properties

The mounting global concern over the environmental consequences of petroleum-based plastics has prompted significant research into sustainable alternatives, with bioplastics emerging as a forerunning solution. This systematic review elucidates the multifaceted synthesis processes of bioplastics, which are derived from renewable sources such as plant starches, cellulose, and waste materials. The synthesis encompasses stages from raw material selection, pre-treatment, to the incorporation of various additives, with the aim to achieve specific properties in the resultant bioplastics. A substantial focus of this review lies in comprehensively understanding the role of additives, which serve as the pivotal agents in tailoring the mechanical and thermal characteristics of bioplastics. Additives, including cross-linking agents, plasticizers, fillers, compatibilizers, and reinforcement agents, are critically examined for their influence on attributes such as tensile strength, flexibility, thermal stability, and biodegradability. Factors such as intermolecular interactions, hydrogen bonding, and moisture content, play a determining role towards the resultant properties. The prospects for bioplastics are rapidly expanding, signalling a transformative shift in various applications ranging from eco-friendly packaging to advanced biomedical devices. This article serves as a comprehensive guide to both researchers and industry stakeholders, providing deep insights into the synthesis of bioplastics and the transformative role additives play in their functional properties.

Applying Subcritical Water Extraction to Obtain Bioactive Compounds and Cellulose Fibers from Brewer Spent Grains

Of the three types of waste generated in beer processing, brewer’s spent grain (BSG) is the most abundant and has a high potential for valorization. In this work, defatted BSG (DB) was subjected to an extraction process with subcritical water at different temperatures to obtain extracts rich in phenols and the cellulosic fractions, which were also purified by using hydrogen peroxide (H2O2). The results showed that the dry extracts obtained at 170 °C were richer in phenolics (24 mg Gallic Acid Equivalent (GAE) g−1 DB), but with lower antioxidant capacity (71 mg DB·mg−1 2,2-diphenyl-1-pikryl-hydrazyl). This extract also showed the highest antibacterial potential against L. innocua (80 mg·mL−1) and E. coli (140 mg·mL−1) than those obtained at lower temperatures. The purification of cellulose from the treated residues, using hydrogen peroxide, revealed that DB is a limited source of cellulose material since the bleached fractions showed low yields (20–25%) and low cellulose purity (42–71%), even after four bleaching cycles (1 h) at pH 12 and 8% H2O2. Despite this, the subcritical water extraction method highlights the potential of a simple process as a technological option to convert underutilized side streams like beer bagasse into added-value, potential ingredients for innovative food and pharmaceutical applications.