Cellulose Microfibers Research Articles

Cool roofing tiles derived from recycled corrugated containers

To reduce the heat island effect brought by conventional asphalt roofing products with high solar absorption, we propose a category of self-cleaning and self-cooling composited roofing tile (CRT) made of old corrugated containers (OCC) and tung oil inspired by traditional Chinese oil-paper umbrellas, which can be fabricated at scale and easily recycled for roofing applications. Compared with asphalt shingles, CRTs can improve the solar reflection due to the randomized structure of the cellulose microfibers, contributing to a significant temperature difference of ∼13.2 °C. In addition, they have a high thermal emissivity of 0.93 in the atmospheric window, radiating great amounts of heat into the cold outer space (∼ 3 K). The top layer tung oil film smeared on the OCC pulp fibers transforms the roofing tile from a waterabsorbing to a waterproofing state and significantly enhances the mechanical strength, contributing to a stable thermal performance in outdoor applications. Furthermore, dyed CRTs can selectively reflect visible light for desired colors and effectively reflect near-infrared light to reduce solar heating, which synchronously achieves roof cooling and aesthetic variety. These cheap, eco-friendly, and multifunctional roofing tiles can provide a value-added path for OCC recycling, which may inspire more radiative cooling composites purely from recycling waste towards an energy-saving and sustainable society.

Cellulose microfiber extraction from leftover celery pulp: Chemomechanical treatments, structural, morphological, and thermal characterization

Based on the variety of attractive applicability and structural advantages, cellulose is suggested as a sustainable and environmentally-friendly replacement for petroleum-based materials. Therefore, the current study proposed two chemo-mechanical treatments including bleaching with sodium chlorite and sodium hypochlorite for pure cellulose extraction from leftover celery pulp (Apium graveolens var. dulce). The characterizations of the extracted cellulose fibers were measured and analyzed, by using FT-IR, XRD, optical microscopy, FE-SEM, and TGA analysis. FTIR analysis confirmed the successful removal of non-cellulosic and impurities materials by chemical treatments. Analyzing the X-ray diffraction showed that the proposed chemo-mechanical procedures did not have damaging impacts on the cellulose crystalline structure. Microscopies analysis within optical microscopy and FE-SEM indicated that the diameters of the untreated fibers generally ranged from 100 to 150 μm, while for the treated ones, they ranged from 10 to 15 μm. The TGA results illustrated the higher initial degradation temperatures for the treated samples which led to significant improvement in their thermal stabilities.

Strong, Lightweight, and Shape-Memory Bamboo-Derived All-Cellulose Aerogels for Versatile Scaffolds of Sustainable Multifunctional Materials.

Strong, lightweight, and shape-memory cellulose aerogels have great potential in multifunctional applications. However, achieving the integration of these features into a cellulose aerogel without harsh chemical modifications and the addition of mechanical enhancers remains challenging. In this study, a strong, lightweight, and water-stimulated shape-memory all-cellulose aerogel (ACA) is created using a combination strategy of partial dissolution and unidirectional freezing from bamboo. Benefiting from the firm architecture of cellulose microfibers bridging cellulose nanofibers /regenerated cellulose aggregated layers and the bonding of different cellulose crystal components (cellulose Iβ and cellulose II), the ACA, with low density (60.74mg cm-3 ), possesses high compressive modulus (radial section: 1.2MPa, axial section: 0.96MPa). Additionally, when stimulated with water, the ACA exhibits excellent shape-memory features, including highly reversible compression-resilience and instantaneous fold-expansion behaviors. As a versatile scaffold, ACA can be integrated with hydroxyapatite, carboxyl carbon nanotubes, and LiCl, respectively, via a simple impregnation method to yield functionalized cellulose composites for applications in thermal insulation, electromagnetic interference shielding, and piezoresistive sensors. This study provides inspiration and a reliable strategy for the elaborately structural design of functional cellulose aerogels endows application prospects in various multifunction opportunities.

Potential of Nanocellulose as a Dietary Fiber Isolated from Brewer's Spent Grain.

Steady growth in beer production is increasing the number of by-products named brewers' spent grain. Such by-products are a source of several components, where cellulose is usually present in high amounts. The aim of this study was to develop a protocol to obtain a mix of cellulose microfibers with an average diameter of 8-12 µm and cellulose nanoplatelets with an average thickness of 100 nm, which has several applications in the food industry. The process comprised one alkaline treatment followed by acid hydrolysis, giving a new mix of micro and nanocellulose. This mix was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and laser scanning microscopy corroborating the presence and measurements of the cellulose nanostructure, showing an aspect ratio of up to 500. Finally, we demonstrated that the administration of this new type of nanocellulose allowed us to control the weight of mice (feed intake), showing a significant percentage of weight reduction (4.96%) after 15 days compared with their initial weight, indicating the possibility of using this material as a dietary fiber.

Cellulose microfibers from rice straw: Low-temperature alkali-mediated extraction and functionalization for thermal insulation and electromagnetic shielding

Highly efficient and cost-effective extraction of cellulose biomass from straws is of high significance for the development of eco-friendly materials in the field of sustainable biorefineries, however, the current approaches generally suffer from high solvent toxicity, energy consumption, and environmental pollution. Here, we demonstrate a low-temperature alkali-treating method to prepare cellulose microfibers from rice straw. The underneath mechanism, i.e., entropy-driven separation mediated by cellulose swelling and polymorphic transformation, is disclosed. Notably, the cellulose microfibers are explored to develop thermal insulation materials, which exhibit low relative density (19.7 mg/cm3) and extremely low thermal conductivity (0.037 W·m−1·K−1), surpassing untreated straw powders and even cotton materials. Furthermore, the microfibers can be further constructed into electromagnetic shielding films with a high shielding efficiency of up to 28 dB, blocking over 99 % of electromagnetic waves. These findings pave a foundation for high value-utilization of straw biomass to create high-performance functional green materials.

Techno-Economic Assessment of Peruvian Stipa Ichu Microfibres by Steam Explosion

ABSTRACT Steam explosion as a pre-treatment for lignocellulosic fibers is an eco-friendly technology for obtaining cellulose microfibres. This study used a sustainable process design to produce Stipa Ichu (endemic fiber) cellulose microfibres on a pilot scale. Pseudolignin models and experimental data from recent studies were used to validate and simulate the steam explosion in a range of 150 to 220°C using acetic acid concentrations of 0.1 to 0.3 g/g of fiber. A peak yield of 92% was obtained for lignin recovery. The proposed process, which would produce 5 tons of dried cellulose microfibres per year, is economically feasible with an ROI of 48% and a PBP of 2.45 years. Additionally, the process is environmentally viable, with an E-factor of 9.42.

Flocculation of Cellulose Microfiber and Nanofiber Induced by Chitosan-Xylan Complexes.

This study aims to provide a comprehensive understanding of the key factors influencing the rheological behavior and the mechanisms of natural polyelectrolyte complexes (PECs) as flocculation agents for cellulose microfibers (CMFs) and nanofibers (CNFs). PECs were formed by combining two polyelectrolytes: xylan (Xyl) and chitosan (Ch), at different Xyl/Ch mass ratios: 60/40, 70/30, and 80/20. First, Xyl, Ch, and PEC solutions were characterized by measuring viscosity, critical concentration (c*), rheological parameter, ζ-potential, and hydrodynamic size. Then, the flocculation mechanisms of CMF and CNF suspensions with PECs under dynamic conditions were studied by measuring viscosity, while the flocculation under static conditions was examined through gel point measurements, floc average size determination, and ζ-potential analysis. The findings reveal that PEC solutions formed with a lower xylan mass ratio showed higher intrinsic viscosity, higher hydrodynamic size, higher z-potential, and a lower c*. This is due to the high molecular weight, charge, and gel-forming ability. All the analyzed solutions behave as a typical non-Newtonian shear-thinning fluid. The flocculation mechanisms under dynamic conditions showed that a very low dosage of PEC (between 2 and 6 mg PEC/g of fiber) was sufficient to produce flocculation. Under dynamic conditions, an increase in viscosity indicates flocculation at this low PEC dosage. Finally, under static conditions, maximum floc sizes were observed at the same PEC dosage where minimum gel points were reached. Higher PEC doses were required for CNF suspensions than for CMF suspensions.

Flexoelectric and piezoelectric effects in micro- and nanocellulose films

In this work, we evaluated the flexoelectric and piezoelectric contributions to the overall macroscopic polarization in cellulose films. To this end, the flexoelectric μ31 and transverse effective piezoelectric e31,f coefficients of cellulose films were determined using cantilever beam bending. The experiments were based on theoretical developments allowing to separate the flexoelectric from the piezoelectric contribution, represented by an effective flexoelectric coefficient, μeff, depending on both e31,f and μ31. Five free-standing and stainless steel/cellulose bilayer films were prepared from cellulose showing different morphologies and surface charge degrees: two almost neutral cellulose microfibers (CMF) and three (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized cellulose micro- (TCMF) and nanofibers (TCNF) bearing negative charged groups on the surface.The dielectric properties of the films indicated a low dielectric constant for unmodified CMF, and a huge increase for TEMPO-oxidized samples, which were up to 9 times higher than poly(vinylidene fluoride)-based polymers. TEMPO-oxidized cellulose films exhibited the largest flexoelectric coefficients (almost 7 times higher than those of synthetic polymer dielectrics), which evidenced that the presence of polar groups and surface charge boosted both flexoelectricity and piezoelectricity in unpoled cellulose films. These findings pave the way towards sustainable cellulose-based curvature sensors with large effective flexoelectric coefficients, without the need of preliminary energy consuming poling step.

Thermo-compression process-mediated in-situ cellulose microfibers phosphorylation enables high performant cellulosic paper packaging

With the increasing demand for environmentally friendly alternatives to traditional plastic packaging, the development of sustainable cellulosic-based materials has become a strategic research topic. In this concept, a groundbreaking approach was adopted herein to produce phosphorylated cellulose microfibers (CMFs)-based paper packaging via a one-pot preparation step using a thermo-compression process (150 °C under pression for 45 min) in the presence of diammonium hydrogen phosphate ((NH4)2HPO4, denoted DAP) and urea. This process involves a chemical mechanism leading to the production of phosphorylated cellulosic paper with a very compacted structure induced by the hornification phenomenon. This phenomenon reveals the formation of additional and irreversible strong hydrogen bonds leading thus to an increase of the materials’ crystallinity up to 91%, and to an enhancement of their morphological, thermal stability, flame retardancy, hydrophobicity, water vapor permeability, and mechanical strength properties. To further enhance these properties, and thus their potential applications, the as-produced phosphorylated CMF paper samples were then coated with a thin layer (40 ± 1.11 µm) of poly[ethylene-co-(vinyl acetate)] (EVA) polymer. A comparison of collected properties with those from non-phosphorylated CMFs or from materials prepared using the conventional phosphorylation process clearly demonstrates that the proposed one-pot preparation method led to the production of advanced materials more effective for packaging applications. Overall, the findings associated to this work could be used as a proof-of-concept for the development of sustainable packaging materials, which could be made by following a more efficient and cost-effective manufacturing procedure than current benchmarks.

Physicochemical characteristics of oil palm frond and application of CMF Hydrogel as a natural encapsulant for probiotic

Oil palm solid waste from Indonesia’s large oil palm plantations has enormous potential to meet various human needs. Lb. fermentum InaCC B 1295 (LFB1295) was tested in vitro for viability, acid and bile tolerance, safety assessment, and antioxidant activities as a potential probiotic. The physiochemical characteristics of oil palm frond (OPF) and cellulose microfiber (CMF) were also examined. OPF mainly consisted of carbohydrates, particularly fiber, followed by ash, protein, and fat. The major components of OPF fiber were cellulose, lignin, and hemicellulose. The crystal index of the cellulose from OPF was 93.4%, according to an X-ray diffraction examination. The vibrations that stretch the cellulose’s -OH group were discovered via FTIR analysis at 3420.05 cm-1. The viability of LFB1295 was maintained at 9.99 log CFU/g by CMF from OPF. The persistence of LFB1295 under bile-containing conditions and at low pH was characterized by a decrease in cell number at 2.03 and 1.56 log CFU/mL, respectively. Based on its ability to repel hydrogen peroxide, neutralize DPPH radicals, and actively neutralize hydroxyl radicals. LFB1295, encapsulated in CMF hydrogel of OPF, has good antioxidant characteristics. This fact is demonstrated by the value of Hydroxyl radical scavenging activity, which is 78.43%, and the capacity to scavenge DPPH radicals, which has an inhibition and IC50 of 47.28%. Encapsulated LFB1295 by CMF hydrogel from OPF passed all in vitro safety tests.

Extraction and Modification of Cellulose Microfibers Derived from Biomass of the Amazon Ochroma pyramidale Fruit

Microfibers are important to several areas of human lifestyle, and the knowledge about their physicochemical characteristics allows for proposing new technological applications. The in natura microfiber of Ochroma pyramidale fruit (IN sample) and its extracted pulp (PU sample) were evaluated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetry and Differential Scanning Calorimetry (TG/dTG and DSC). Microfibers were composed mainly of (68 ± 1)% holocellulose, (35.8 ± 0.1)% cellulose, (32 ± 3)% lignin and (3.7 ± 0.3)% extractives. The XRD pattern of the PU sample revealed that the mercerization process resulted in the change of the cellulose crystal structure from Iα type (triclinic) to type II (monoclinic). The SEM technique showed that the IN sample presented regular cylindrical/hollow-shaped wire-like microfibers with diameters ranging from 5 µm to 25 µm. However, the mercerization process changed their natural morphology. A significant change in the FTIR spectra after the removal of hemicellulose and lignin components was observed: weak bands at 1739 cm−1 (C=O stretching of lignin and hemicellulose fractions), 1463 cm−1 (CH3 of lignin) and 1246 cm−1 (C-O of lignin) were still observed in the PU sample, indicating that the lignin was not completely removed due to the natural difficulty of isolating pure cellulose. The TG/dTG and DSC evaluation revealed a temperature increase of the second thermal event (starting at 235 °C) in the PU sample, which was assigned to the cellulose and residual hemicellulose degradation. Then, this work aimed to disseminate and characterize a microfiber with unusual characteristics still little explored by the scientific community, as well as its cellulosic pulp, providing information that may be useful in its application in different industries, enabling the positive development of new biocompatible, renewable and sustainable materials.

Mitigating self-desiccation of cement composites via cellulose microfibers: Evidence of the microscopic behavior

Water-saturated cellulose microfibers (CMFs) incorporated into fresh cement composites can mitigate microcracking induced by self-desiccation during drying. This study utilized a nonlinear impact resonance acoustic spectroscopy (NIRAS) technique to elucidate the mechanism underlying the CMF-driven mitigation of self-desiccation. The hysteresis nonlinearity parameter (α) from the NIRAS was used to quantify the microstructural changes in three different mixtures (0 0.3 and 1% dosages of CMFs). Computed tomography (CT) compression tests and periodic measurements of mass and resonance frequency were performed to obtain more insights into mitigating self-desiccation. Supported by the collected data the results show a remarkable reduction in α over time confirming high sensitivity of α to the microstructural change. Furthermore the trend of α was consistent with the pore size distribution estimated by the CT test which provides quantitative evidence to support the mitigation of self-desiccation promoted by CMFs. We envision that these findings can be used as guidelines for enhancing the durability of cement composites facilitated by CMFs.

Structure and properties of monolithic cellulose aerogels prepared from oil palm cellulose microfiber (OPMFC) using alkaline/urea solvent system potentially for solar thermal applications

Structure and properties of monolithic cellulose aerogels prepared from oil palm cellulose microfiber (OPMFC) using alkaline/urea solvent system potentially for solar thermal applications

Biomass-based single- and double-network hydrogels derived from cellulose microfiber and chitosan for potential application as plant growing substrate

A series of hydrogels were synthesized from renewable and low-cost micro-sized cellulose fiber. The single-network hydrogel was composed of cellulose fiber and a small amount of another polysaccharide, chitosan, which ‘glued’ individual cellulose fiber pieces together through Schiff-base bonding. The double-network hydrogel was constructed by adding a secondary network, the covalently crosslinked polyacrylamide, into the single-network hydrogel, which was synthesized by conducting Schiff-base reaction and free radical polymerization at the same time in a facile one-pot process. In both single- and double-network hydrogels, cellulose fiber constituted the dominant component. Both types of hydrogels exhibited good swelling properties. The double-network hydrogel showed much improved stability against soaking in water and higher salt tolerance. Germination experiment with choy sum seeds sowed on hydrogel surface showed that the seeds were able to germinate and further develop roots, shoots, and true leaves, demonstrating the potential of the biomass-derived hydrogels for soilless plant growing applications.

Vapor Barrier Membranes Based on Polylactic acid and Cellulose Microfibers for the Building Envelope Application

Vapor Barrier Membranes Based on Polylactic acid and Cellulose Microfibers for the Building Envelope Application

All-natural and high-performance structural material based on lignin-reinforced cellulose

Sustainable materials derived from lignocellulosic resources are attractive alternatives to ubiquitous petrochemical plastics. However, it remains a huge challenge to improve the mechanical properties of lignocellulosic materials through efficient and low-energy processing strategy. Herein, we report a facile lignin-reinforced cellulose strategy to manufacture an all-natural and high-performance structural material from bamboo particles via partial delignification followed by hot-pressing. Partial delignification can regulate the amount of lignin in the bamboo particles and release internal cellulose microfibers. The subsequent hot-pressing drives residual lignin into the cellulose matrix to form a dense structure, which acts as a polyphenolic binder to improve the performance of the structural material. The obtained lignin-reinforced cellulose plate (LRCP) demonstrates high isotropic flexural strength (∼162 MPa), which is higher than that of natural bamboo and typical petrochemical plastics. Moreover, LRCP shows outstanding toughness (∼2.58 MPa m1/2), excellent compressive strength (∼178 MPa), improved wet stability and superior flame resistance. LRCP is all-natural and eco-friendly without the need for additional chemical cross-linking reagents. We believe that this facile and cost-effective strategy provides a promising way to process lignocellulosic resources into all-natural and high-performance structural materials that can serve as powerful plastic alternatives in the future.

PH dependence of glyphosate adsorption from aqueous solution using a cationic cellulose microfibers (cCMF) biosorbent

Abstract Currently, the agricultural sector is responsible for the contamination of groundwater and springs due to the excessive use of pesticides, which represents a risk to human and environmental health. Among pesticides, glyphosate is the most used herbicide to increase agricultural production, however, it can cause intoxication in humans and has been classified as a potentially carcinogenic agent. Alternatives for removing these contaminants from water have been studied and discussed, including biosorption, a physical-chemical process that removes substances from solutions using a natural and renewable material. In this sense, this work studied the process to obtain cationic cellulose microfibers (cCMF) from sugarcane bagasse residue, by cellulose isolation followed by cationization reaction with Girard T reagent to promote a new adsorbent for glyphosate removal from water. It was observed that cCMF structure maintains the fibrillar morphology after the microfiber production (1.375 mmol g−1 oxidation degree). Results of zero charge of cCMF microfibers showed an isoelectric point pH = 5.4 ± 0.016 and the highest adsorption capacity was reached at pH 14 (59.21 %), showing a clear pH dependence on the adsorption process. Thereby, the cCMF can be produced from sugarcane bagasse residue being applied as a potential biomaterial for removing organic compounds from water.

Considerations about highly crystalline cellulose microfiber additive from Eucalyptus grandis for 3D-printing acrylonitrile butadiene styrene filament

The current work aimed to produce acrylonitrile butadiene styrene (ABS) filament with cellulose microfibers additive for three-dimensional (3D)-printing and perform initial mechanical characterizations. 3D printing is a Fourth Industrial Revolution enabling technology aimed at smart production process. Cellulose is an organic molecule extremely common in nature with potential application as materials reinforcement. Highly crystalline cellulose microfibers were extracted from certified Eucalyptus grandis wood. E. grandis is a species native to Australia, but widely used in reforestation initiatives on a global scale. Cellulose microfiber was inserted at 0.5% in weight into commercial ABS to produce filaments for 3D printing. After the production of pure ABS and ABS with microcellulose filaments, specimens were printed using fused deposition modeling for traction, flexion, and impact tests, in addition to measuring the melt flow index. The results between the two materials were compared, revealing that most of the mechanical properties were similar within the limits of experimental errors, but the strain at break in the traction test was improved in microfibers composite, in addition to an improvement in the elastic modulus and stress at break in flexion test. On melt flow index measurement, both materials were found to be considerably more fluid than the polymer from commercial producer sources. This is an indication that the ABS degraded throughout the process, losing molar mass. However, our work demonstrated that it is possible to add highly crystalline cellulose microfibers to ABS to form filaments for 3D printing.

A biodegradable cellulose fibrous membrane comprising cellulose microfibers and nanofibrils with enhanced interaction through crosslinking structure

AbstractThe petroleum‐based materials are widely used in daily life, which are inherently tough to degrade, increasingly polluting the environment and affecting human health. Cellulose fibrous membrane, the ubiquitous, low‐cost, and biodegradable material, can serve as a promising substitute. Herein, the biodegradable cellulose fibrous membranes were constructed with cellulose microfibers made from wood particle fibers (WPF) and the mechanical properties were enhanced by introducing the crosslinking system. The cellulose fibrous membrane made of the original WPF showed low tensile strength (0.1 KPa) and elastic modulus (1 MPa). By adding 10 wt% cellulose nanofibrils (CNFs), the prepared cellulose fibrous membrane exhibited an increase in tensile strength (0.525 MPa) and elastic modulus (535 MPa), respectively. To further improve the mechanical properties, the sodium alginate (SA) and Ca2+ were introduced to crosslink with the CNFs and promote the interaction among SA, CNFs and microfibers, which resulted in a substantial increase in tensile strength (5.62 MPa) and elastic modulus (1660 MPa) due to the formation of the interpenetrating entanglements and anchors. The normalized fracture energy of crosslinked hybrid cellulose fibrous membrane was 100.38 times higher than that of the original WPF membrane and 16 times higher than that of the un‐crosslinked cellulose membrane comprising CNFs. This strategy can serve as the foundation for preparing a mechanically enhanced cellulose fibrous membrane via crosslinking, making it possible to replace petroleum‐based plastics.

Flame-Retardant and Fire-Sensing Packaging Papers Enabled by Diffusion-Driven Self-Assembly of Graphene Oxide and Branched Polyethyleneimine Coatings

Paper has gained popularity as a packaging material due to its reduced environmental impact compared with non-degradable alternatives. However, its flammability poses safety risks, prompting research on enhancing its flame retardancy. This work introduces a diffusion-driven self-assembly strategy (DDSAS) to create a functional graphene oxide (GO) coating on various packaging papers. DDSAS involves infiltrating the paper’s cellulose microfiber network with branched polyethyleneimine (b-PEI), which binds firmly to cellulose microfibers. Electrostatic interactions between GO and b-PEI then drive GO assembly into a densely stacked, layered structure on the paper surface. This GO structure provides a physical barrier against flames and generates incombustible gases (CO2, H2O, NO2, and NO) when heated, diluting the surrounding oxygen concentration and acting as a heat insulation layer. These factors increase the flame retardancy of treated papers ten-fold. Additionally, the gradual reduction of GO upon heating forms reduced graphene oxide (rGO) on the paper, significantly increasing its electrical conductivity. As a result, the flame-retardant papers not only prevent the fire from spreading but can also act as fire sensors by triggering an alarm signal at the early stages of contact with fire. In summary, this work offers a rational strategy for designing and manufacturing flame-retardant paper packaging materials.