Nanocellulose for Paper and Textile Coating: The Importance of Surface Chemistry

Transforming textile waste into nanocellulose for a circular future

The expansion of the textile industry and improvements in living standards have led to increased cotton textile production, resulting in a rise in textile waste, with cotton accounting for 24% of total textile waste. Effective waste management through recycling and reuse is crucial to reducing global waste production. Nanocellulose has diverse applications in environmental, geotechnical, food packaging, and biomedical engineering areas. As interest in nanocellulose's unique properties grows, cotton-based textile waste emerges as a promising source for nanocellulose development. However, there is a notable lack of comprehensive reviews on the extraction of nanocellulose from textile waste as a sustainable biomaterial. This paper aims to address this gap by exploring current extraction processes, properties, and recent applications of nanocellulose derived from textile waste. We discussed (1) the potential of nanocellulose resources from different textile wastes, (2) a comparison of the various extraction methods, (3) the functionalization technology and the potential application of such nanocellulose in the textile industry, and (4) the life cycle assessment (LCA) and potential gap of the current technology. It also emphasizes the potential reintegration of extracted nanocellulose into the textile industry to manufacture high-value products, thus completing the loop and strengthening the circular economy.

A Simple and Cost-Effective FeCl3-Catalyzed Functionalization of Cellulose Nanofibrils: Toward Adhesive Nanocomposite Materials for Medical Implants

In the present work, we explored Lewis acid catalysis, via FeCl3, for the heterogeneous surface functionalization of cellulose nanofibrils (CNFs). This approach, characterized by its simplicity and efficiency, facilitates the amidation of nonactivated carboxylic acids in carboxymethylated cellulose nanofibrils (c-CNF). Following the optimization of reaction conditions, we successfully introduced amine-containing polymers, such as polyethylenimine and Jeffamine, onto nanofibers. This introduction significantly enhanced the physicochemical properties of the CNF-based materials, resulting in improved characteristics such as adhesiveness and thermal stability. Reaction mechanistic investigations suggested that endocyclic oxygen of cellulose finely stabilizes the transition state required for further functionalization. Notably, a nanocomposite, containing CNF and a branched low molecular weight polyethylenimine (CNF-PEI 800), was synthesized using the catalytic reaction. The composite CNF-PEI 800 was thoroughly characterized having in mind its potential application as coating biomaterial for medical implants. The resulting CNF-PEI 800 hydrogel exhibits adhesive properties, which complement the established antibacterial qualities of polyethylenimine. Furthermore, CNF-PEI 800 demonstrates its ability to support the proliferation and differentiation of primary human osteoblasts over a period of 7 days.

Extraction of Nanocellulose from the Residue of Sugarcane Bagasse Fiber for Anti-Staphylococcus aureus (S. aureus) Application

Nanocellulose contains a large number of hydroxyl groups that can be used to modify its surface due to its structure. Owing to its appealing features, such as high strength, great stiffness, and high surface area, nanocellulose is currently gaining popularity in research and industry. The extraction of nanocellulose from the leftover bagasse fiber from sugarcane production by alkaline and acid treatment was successful in this study, with a production yield of 55.6%. The FTIR and XPS results demonstrated a difference in the functional and chemical composition of untreated sugarcane bagasse and extracted nanocellulose. SEM imaging was used to examined the size of the nanocellulose with ImageJ software v1.8.0. TGA, DTG, and XRD analyses were also performed to demonstrate the successful extraction of nanocellulose in terms of its morphology, thermal stability, and crystal structure before and after extraction. The anti-S. aureus activity of the extracted nanocellulose was discovered by using an OD600 test and a colony counting method, and an inhibitory rate of 53.12% was achieved. According to the results, nanocellulose produced from residual sugarcane bagasse could be employed as an antibacterial agent.

Lignocellulosic-biomolecules conjugated systems: green-engineered complexes modified by covalent linkers

Lignocellulosic biomass represents an abundant and eco-friendly material widely explored in recent years. The main lignocellulosic fractions include cellulose, hemicellulose, and lignin. Nonetheless, the heterogeneity and complexity of these components pose challenges in achieving the desired properties. Conversely, their attractive functional groups can covalently link with other biomolecules, facilitating the creation and enhancement of material properties. Lignocellulosic molecules can form different linkages with other biomolecules through classic and modern methods. Bioconjugation has emerged as a suitable alternative to create new nuances, empowering the linkage between lignocellulosic materials and biomolecules through linkers. These conjugates (lignocellulosic-linkers-biomolecules) attract attention from stakeholders in medicine, chemistry, biology, and agriculture. The plural formations of these biocomplexes highlight the significance of these arrangements. Therefore, this review provides an overview of the progress of lignocellulosic-biomolecule complexes and discusses different types of covalent bioconjugated systems, considering the formation of linkers, applicability, toxicity, and future challenges.

Recent advances in TEMPO-oxidized cellulose nanofibers: Oxidation mechanism, characterization, properties and applications

Cellulose is the richest renewable polymer source on the earth. TEMPO-mediated oxidized cellulose nanofibers are deduced from enormously available wood biomass and functionalized with carboxyl groups. The preparation procedure of TOCNFs is more environmentally friendly compared to other cellulose, for example, MFC and CNCs. Due to the presence of functional carboxyl groups, TOCNF-based materials have been studied widely in different fields, including biomedicine, wastewater treatment, bioelectronics and others. In this review, the TEMPO oxidation mechanism, the properties and applications of TOCNFs are elaborated. Most importantly, the recent advanced applications and the beneficial role of TOCNFs in the various abovementioned fields are discussed. Furthermore, the performances and research progress on the fabrication of TOCNFs are summarized. It is expected that this timely review will help further research on the invention of novel material from TOCNFs and its applications in different advanced fields, including biomedicine, bioelectronics, wastewater treatment, and the energy sector.

The adsorption routes of 4IR technologies for effective desulphurization using cellulose nanocrystals: Current trends, challenges, and future perspectives

The combustion of liquid fuels as energy sources for transportation and power generation has necessitated governments worldwide to direct petroleum refineries to produce sulphur-free fuels for environmental sustainability. This review highlights the novel application of artificial intelligence for optimizing and predicting adsorptive desulphurization operating parameters and green isolation conditions of nanocellulose crystals from lignocellulosic biomass waste. The shortcomings of the traditional modelling and optimization techniques are stated, and artificial intelligence's role in overcoming them is broadly discussed. Also, the relationship between nanotechnology and artificial intelligence and the future perspectives of fourth industrial revolution (4IR) technologies for optimization and modelling of the adsorptive desulphurization process are elaborately discussed. The current study surveys different adsorbents used in adsorptive desulphurization and how biomass-based nanocellulose crystals (green adsorbents) are suitable alternatives for achieving cleaner fuels and environmental sustainability. Likewise, the present study reports the challenges and potential solutions to fully implementing 4IR technologies for effective desulphurization of liquid fuels in petroleum refineries. Hence, this study provides insightful information to benefit a broad audience in waste valorization for sustainability, environmental protection, and clean energy generation.

Upcycling Food By-products: Characteristics and Applications of Nanocellulose

Rising global food prices and the increasing prevalence of food insecurity highlight the imprudence of food waste and the inefficiencies of the current food system. Upcycling food by-products holds significant potential for mitigating food loss and waste within the food supply chain. Food by-products can be utilized to extract nanocellulose, a material that has obtained substantial attention recently due to its renewability, biocompatibility, bioavailability, and a multitude of remarkable properties. Cellulose nanomaterials have been the subject of extensive research and have shown promise across a wide array of applications, including the food industry. Notably, nanocellulose possesses unique attributes such as a surface area, aspect ratio, rheological behavior, water absorption capabilities, crystallinity, surface modification, as well as low possibilities of cytotoxicity and genotoxicity. These qualities make nanocellulose suitable for diverse applications spanning the realms of food production, biomedicine, packaging, and beyond. This review aims to provide an overview of the outcomes and potential applications of cellulose nanomaterials derived from food by-products. Nanocellulose can be produced through both top-down and bottom-up approaches, yielding various types of nanocellulose. Each of these variants possesses distinctive characteristics that have the potential to significantly enhance multiple sectors within the commercial market.

Evaluation of steam explosion pretreatment on the cellulose nanocrystals (CNCs) yield from poplar wood

The high sulfuric acid concentration used in the hydrolysis of cellulose to isolate cellulose nanocrystals (CNCs) leads to low yields due to the dissolution of both amorphous and semi-crystalline cellulose. The present study explored the use of steam explosion pretreatment before acid hydrolysis to enhance the crystallization of semi-crystalline/ non-crystalline cellulose and generating new CNC precursors with poplar wood as feedstock. The crystallinity of steam exploded poplar wood increased 1.3-fold compared to untreated poplar wood. Consequently, the overall yield of CNCs of steam exploded poplar wood increased 2.5-fold compared to untreated poplar wood. Moreover, the steam explosion pretreatment did not affect the quality of the CNCs with regard to the crystal size, crystallinity, and colloidal stability. Whereas the thermal stability of the CNCs increased due to the steam explosion pretreatment. This study demonstrates a simple and scalable pretreatment step that can significantly improve the CNCs yield from the acid hydrolysis step thereby improving the overall economics and commercial viability.

Effect of a Nanocellulose Addition on the Mechanical Properties of Paper

Nowadays, the emphasis is on increasing the durability of all products. For this reason, it is also advisable to look into extending the durability of paper products. The main reason for using flax pulp is that flax and cotton pulp are widely used for the production of banknotes due to their higher strength. This paper deals with flax pulp with the addition of nanocellulose, which should further enhance the mechanical properties of the pulp. The tensile strength, breaking length, and tensile energy absorption index were evaluated as the key mechanical properties. At the same time, the effect of the addition of nanocellulose, whether it was added to the pulp mass or applied to the later produced paper as a spray or coating, was tested in comparison to paper without the addition of nanocellulose. The best mechanical properties, i.e., tensile strength, were achieved for the highest addition of 5% of nanocellulose into the pulp, at 24.3 Nm∙g-1, and for the coating application, at 28.7 Nm∙g-1, compared to the flax pulp without the addition, where the tensile strength was 20.5 Nm∙g-1. The results of this research are used for the assessment of nanocellulose as a natural compatible additive to enhance the strength properties of cellulose-based materials.

Cellulose-Based Conductive Materials for Energy and Sensing Applications

Cellulose-based conductive materials (CCMs) have emerged as a promising class of materials with various applications in energy and sensing. This review provides a comprehensive overview of the synthesis methods and properties of CCMs and their applications in batteries, supercapacitors, chemical sensors, biosensors, and mechanical sensors. Derived from renewable resources, cellulose serves as a scaffold for integrating conductive additives such as carbon nanotubes (CNTs), graphene, metal particles, metal-organic frameworks (MOFs), carbides and nitrides of transition metals (MXene), and conductive polymers. This combination results in materials with excellent electrical conductivity while retaining the eco-friendliness and biocompatibility of cellulose. In the field of energy storage, CCMs show great potential for batteries and supercapacitors due to their high surface area, excellent mechanical strength, tunable chemistry, and high porosity. Their flexibility makes them ideal for wearable and flexible electronics, contributing to advances in portable energy storage and electronic integration into various substrates. In addition, CCMs play a key role in sensing applications. Their biocompatibility allows for the development of implantable biosensors and biodegradable environmental sensors to meet the growing demand for health and environmental monitoring. Looking to the future, this review emphasizes the need for scalable synthetic methods, improved mechanical and thermal properties, and exploration of novel cellulose sources and modifications. Continued innovation in CCMs promises to revolutionize sustainable energy storage and sensing technologies, providing environmentally friendly solutions to pressing global challenges.

Harnessing Nature's Ingenuity: A Comprehensive Exploration of Nanocellulose from Production to Cutting-Edge Applications in Engineering and Sciences

Primary material supply is the heart of engineering and sciences. The depletion of natural resources and an increase in the human population by a billion in 13 to 15 years pose a critical concern regarding the sustainability of these materials; therefore, functionalizing renewable materials, such as nanocellulose, by possibly exploiting their properties for various practical applications, has been undertaken worldwide. Nanocellulose has emerged as a dominant green natural material with attractive and tailorable physicochemical properties, is renewable and sustainable, and shows biocompatibility and tunable surface properties. Nanocellulose is derived from cellulose, the most abundant polymer in nature with the remarkable properties of nanomaterials. This article provides a comprehensive overview of the methods used for nanocellulose preparation, structure-property and structure-property correlations, and the application of nanocellulose and its nanocomposite materials. This article differentiates the classification of nanocellulose, provides a brief account of the production methods that have been developed for isolating nanocellulose, highlights a range of unique properties of nanocellulose that have been extracted from different kinds of experiments and studies, and elaborates on nanocellulose potential applications in various areas. The present review is anticipated to provide the readers with the progress and knowledge related to nanocellulose. Pushing the boundaries of nanocellulose further into cutting-edge applications will be of particular interest in the future, especially as cost-effective commercial sources of nanocellulose continue to emerge.

Advanced Sustainable Trilayer Cellulosic "Paper Separator" Functionalized with Nano-BaTiO3 for Applications in Li-Ion Batteries and Supercapacitors

In the quest of developing a sustainable, low-cost and improved separator membrane for application in energy storage devices like lithium-ion batteries (LIBs) and supercapacitors (SCs), here we fabricated a trilayer cellulose-based paper separator engineered with nano-BaTiO₃ powder. A scalable fabrication process of the paper separator was designed step-by-step by sizing with poly(vinylidene fluoride) (PVDF), thereafter impregnating nano-BaTiO₃ in the interlayer using water-soluble styrene butadiene rubber (SBR) as the binder and finally laminating the ceramic layer with a low-concentration SBR solution. The fabricated separators showed excellent electrolyte wettability (216-270%), quicker electrolyte saturation, increased mechanical strength (43.96-50.15 MPa), and zero-dimensional shrinkage up to 200 °C. The electrochemical cell comprising graphite|paper separator|LiFePO₄ showed comparable electrochemical performances in terms of capacity retention at different current densities (0.05-0.8 mA/cm²) and long-term cycleability (300 cycles) with coulombic efficiency >96%. The in-cell chemical stability as tested for 8 weeks revealed a nominal change in bulk resistivity with no significant morphological changes. The vertical burning test as performed on a paper separator showed excellent flame-retardant property, a required safety feature for separator materials. To examine the multidevice compatibility, the paper separator was tested in supercapacitors, delivering a comparable performance to that of a commercial separator. The developed paper separator was also found to be compatible with most of the commercial cathode materials such as LiFePO₄, LiMn₂O₄, and NCM111.

Polyelectrolyte Coatings-A Viable Approach for Cultural Heritage Protection

The continuous degradation of cultural heritage artifacts (due to different factors, including the rising air pollution, climate change or excessive biological activity, among others) requires the continuous development of protection strategies, technologies and materials. In this regard, polyelectrolytes have offered effective ways to fight against degradation but also to conserve the cultural heritage objects. In this review, we highlight the key developments in the creation and use of polyelectrolytes for the preservation, consolidation and cleaning of the cultural heritage artifacts (with particular focus on stone, metal and artifacts of organic nature, such as paper, leather, wood or textile). The state of the art in this area is presented, as well as future development perspectives.

Isolation of Pure Lignin and Highly Digestible Cellulose from Defatted and Steam-Exploded Cynara cardunculus

In this work, a three-step approach to isolate the main components of lignocellulosic cardoon, lignin and cellulose, was investigated. The raw defatted biomass, Cynara cardunculus, after steam explosion was subjected to a mild organosolv treatment to extract soluble lignin (L1). Then, enzymatic hydrolysis was performed to achieve decomposition of the saccharidic portion into monosaccharides and isolate residual lignin (L2). The fractionation conditions were optimized to obtain a lignin as less degraded as possible and to maximize the yield of enzymatic hydrolysis. Furthermore, the effect of the use of aqueous ammonia as an extraction catalyst on both fractions was studied. Each fraction was characterized by advanced techniques, such as elemental analysis and ³¹P nuclear magnetic resonance (NMR), ¹³C-¹H two-dimensional (2D)-NMR, attenuated total reflectance-Fourier transform infrared (ATR-FTIR), and UV-vis spectroscopies for lignin and X-ray diffraction (XRD), Klason compositional analysis, elemental analysis, and ATR-FTIR spectroscopy for cellulose-rich fractions. The impact of the cellulose-rich fraction composition and crystallinity was also correlated to the efficiency of the hydrolysis step, performed using the enzymatic complex Cellic CTec3.

Antibacterial and degradation properties of dialdehyded and aminohexamethylated nanocelluloses

Dialdehyde cellulose nanofibrils (CNF) and nanocrystals (CNC) were prepared via periodate oxidation (CNF/CNC-ox) and subsequently functionalized with hexamethylenediamine (HMDA) via a Schiff-base reaction, resulting in partially crosslinked micro-sized (0.5-10 μm) particles (CNF/CNC-ox-HMDA) with an aggregation and sedimentation tendency in an aqueous media, as assessed by Dynamic Light Scattering and Scanning Electron Microscopy. The antibacterial efficacy, aquatic in vivo (to Daphnia magna) and human in vitro (to A594 lung cells) toxicities, and degradation profiles in composting soil of all forms of CNF/CNC were assessed to define their safety profile. CNF/CNC-ox-HMDA exhibited higher antibacterial activity than CNF/CNC-ox and higher against Gram-positive S. aureus than Gram-negative E. coli, yielding a bacteria reduction of >90 % after 24 h of exposure at the minimum (≤2 mg/mL), but potentially moderately/aquatic and low/human toxic concentrations (≥50 mg/L). The presence of anionic, un/protonated amino-hydrophobized groups in addition to unconjugated aldehydes of hydrodynamically smaller (<1 μm) CNC-ox-HMDA increased the reduction of both bacteria to log 9 at ≥4 mg/mL and their bactericidal activity. While only CNF/CNC-ox can be considered as biosafe and up to >80 % biodegradable within 24 weeks, this process was inhibited for the CNF/CNC-ox-HMDA. This indicated their different stability, application and disposal after use (composting vs. recycling).