Lignocellulosic Film Research Articles

GEM Parçacık Dedektörlerinde Lignoselülozik Malzeme Kullanım Potansiyeli

This study investigates the potential use of lignocellulosic material for Gas Electron Multiplier (GEM) foils in high-energy physics experiments. A 50 µm thick lignocellulosic film was created using a scattering method, and both surfaces were coated with a 2 µm thick copper electrode layer. Electrical characterization studies were conducted to assess the suitability of lignocellulosic material in GEM detectors. To ensure consistent atmospheric conditions during measurements, a special chamber was designed to monitor temperature and humidity values over time using an SHT3x sensor module and Rense Temperature/Humidity Meter. Electrical measurements were performed using a Keithley 4200 semiconductor characterization system, and I-V curves showing the current-voltage relationship under different atmospheric conditions were plotted. The results demonstrate the potential for developing sustainable and efficient detectors for various high-energy physics experiments using GEM detectors with lignocellulosic foils. This study comprehensively presents the advantages and disadvantages of using lignocellulosic material in GEM foils and contributes to the development of more environmentally friendly alternatives for GEM detector manufacturing.

Strong and flexible lignocellulosic film fabricated via a feasible molecular remodeling strategy

Biomass-derived sustainable film is a promising alternative to synthetic plastic, but hampered by strength, toughness and flexibility trade-off predicament. Here, a feasible and scalable strategy was proposed to fabricate strong and flexible lignocellulosic film through molecular reconstruction of cellulose and lignin. In this strategy, polyphenol lignin was absorbed and wrapped on the surface of cellulose fiber, forming strong interfacial adhesion and cohesion via intramolecular and intermolecular hydrogen bonding. Further, covalent ether bond was generated between the hydroxyl groups of lignocellulose to form chemical cross-linking network induced by epichlorohydrin (ECH). The synergistic effect of hydrogen bonding and stable chemical cross-linking enabled the resultant lignocellulosic film (ELCF) with outstanding mechanical strength of 132.48 MPa, the elongation at break of 9.77 %, and toughness of 9.77 MJ·m−3. Notably, the integration of polyphenol lignin synergistically improved the thermal stability, water resistance, UV-blocking performances of ELCF. Importantly, after immersion for 30 d, ELCF still possessed high wet strength of 70.38 MPa, and elongation at break of 7.70 %, suggesting excellent and durable mechanical performances. Moreover, ELCF could be biodegraded in the natural soil. Therefore, this study provides a new and versatile approach to reconstruct highly-performance lignocellulosic films coupling strength, toughness with flexibility for promising plastic replacement.

Bio-inspired, UV-blocking, water-stable and antioxidant lignin/cellulose films combining high strength, toughness and flexibility

Lignocellulosic films with good properties are prepared by constructing sacrificial networks of hydrogen and coordination bonds, and are expected to be used in several emerging fields.

Tuning the functional properties of lignocellulosic films by controlling the molecular and supramolecular structure of lignin

This study investigated the relationships between lignin molecular and supramolecular structures and their functional properties within cellulose-based solid matrix, used as a model biodegradable polymer carrier. Two types of derivatives corresponding to distinct structuration levels were prepared from a single technical lignin sample (PB1000): phenol-enriched oligomer fractions and colloidal nanoparticles (CLP). The raw lignin and its derivatives were formulated with cellulose nanocrystals or nanofibrils to prepare films by chemical oxidation or pressure-assisted filtration. The films were tested for their water and lignin retention capacities, radical scavenging capacity (RSC) and antimicrobial properties. A structural investigation was performed by infrared, electron paramagnetic resonance spectroscopy and microscopy. The composite morphology and performance were controlled by both the composition and structuration level of lignin. Phenol-enriched oligomers were the compounds most likely to interact with cellulose, leading to the smoothest film surface. Their RSC in film was 4- to 6-fold higher than that of the other samples. The organization in CLP led to the lowest RSC but showed capacity to trap and stabilize phenoxy radicals. All films were effective against S. aureus (gram negative) whatever the lignin structure. The results show the possibility to tune the performances of these composites by exploiting lignin multi-scale structure.

In-situ lignin drives lytic polysaccharide monooxygenases to enhance enzymatic saccharification

Recently low-molecular lignin was reported to activate lytic polysaccharide monooxygenases (LPMOs) to oxidize cellulose. However, whether lignin formed in cell wall can play the role as electron donor for LPMOs is still largely unknown due to the complex ultrastructure of lignocellulosic biomass. In this study, we presented a new strategy to elucidate in-situ lignin function in LPMOs reaction. A lignocellulosic mimicking model was used as substrate, which was equipped with a polysaccharide template of self-assembled bacterial cellulose film and synthesized lignin. Remarkably, it has been demonstrated that lignin polymer deposited on cellulose can reduce LPMOs in-situ for cellulose oxidation and then boost cellulose hydrolysis, and the cellulose conversion ratio of the mimicked lignocellulosic film was increased by 26.0%. More importantly, lignin in-situ might exceed the well-known reductant of ascorbic acid to drive LPMOs for cellulase enzymatic hydrolysis with equivalent cellulose oxidation efficiency and extremely lower H2O2 generation, avoiding the inactivation of enzymes. The maximum H2O2 yield from lignin-driven LPMO reaction was 75.8% lower than that from ascorbic acid-driven reaction. Therefore, by using the lignocellulosic mimicking model, we have elucidated the function of in-situ lignin in boosting enzymatic hydrolysis. Such understanding could significantly promote current utilization of LPMOs in lignocellulosic biorefinery.

Atomic force microscopy reveals how relative humidity impacts the Young’s modulus of lignocellulosic polymers and their adhesion with cellulose nanocrystals at the nanoscale

Lignocellulosic biomass is receiving growing interest as a renewable source of biofuels, chemicals and materials. Lignocellulosic polymers and cellulose nanocrystals (CNCs) present high added-value potential in the nanocomposite field, but some issues have to be solved before large-scale applications. Among them, the interaction between polymers at the nanoscale and the effect of the external parameters on the mechanical properties have to be more precisely investigated. The present study aims at evaluating how the relative humidity affects the reduced Young’s modulus of lignocellulosic films prepared with crystalline cellulose, glucomannan, xylan and lignin and how relative humidity changes their nanoscale adhesion properties with CNCs. Using atomic force microscopy and force volume experiments with CNC-functionalized levers, increasing the relative humidity is shown to decrease the Young’s modulus values of the different films and promote their adhesion forces with CNCs. In particular, CNCs more strongly interact with glucomannan and lignin than xylan, and in the case of lignin, the oxidation of the film promotes strong variations in the adhesion force. Such results allow to better understand the lignocellulosic film properties at the nanoscale, which should lead to an improvement in the production of new highly added-value composites.

Real Time and Quantitative Imaging of Lignocellulosic Films Hydrolysis by Atomic Force Microscopy Reveals Lignin Recalcitrance at Nanoscale.

Lignocellulosic biomass is considered as a sustainable source of energy and chemicals, but its recalcitrance to bioconversion still limits its use. In this paper, a strategy based on two aspects was developed to improve our knowledge on the lignin recalcitrance to enzymatic hydrolysis. First, lignocellulosic films of cellulose nanofibrils (CNFs) with increasing content of lignin (up to 40%) were prepared. Thanks to in situ real time Atomic Force Microscopy (AFM) measurements during the hydrolysis and by comparison with biochemical assays, the use of such films allows to fully assess the importance of the lignin content and of the arrangement between CNFs and lignin on the hydrolysis efficiency. In a second time, contrary to other studies by AFM which only followed a specific structure during enzymatic processes mostly on simple systems (CNFs or cellulose nanocrystals), a quantitative analysis of in-situ time-lapse measurements was developed.Itenablesto accurately address lignocellulosic biomass recalcitrance mechanisms mediated by lignin at nanoscale. Such analysis could pave the way for the use of a quantitative criteria to visualize in situ deconstruction of complex lignocellulosic substrates. Coupling the use of lignocellulosic films and dynamical AFM quantitative analysis to follow the evolution of the structure at nanoscale might lead to an effective targeting of new promising bioconversion strategies.

Lignocellulosic Film as a Valid Tool to Investigate Inhibitions to Cellulose Enzymatic Hydrolysis

The complex supramolecular structure of lignocellulose makes it difficult to clarify the recalcitrance to enzymatic digestibility. As an extensively used model mimicking the plant cell wall, assembled lignocellulosic film was applied to investigate inhibition factors of enzymatic hydrolysis for the first time. Xylan was deposited and then a model lignin compound was synthesized to equip bacterial cellulose films. Scanning electron microscopy and surface contact angle analyses revealed that lignin inhibited enzymatic hydrolysis by reducing cellulase accessibility to the cellulose surface. Moreover, xylan showed a good correlation (R2 = 0.969) with the decreased cellulose conversion, although xylan itself did not display inhibitions. The component and surface analyses revealed that xylan enhanced lignin formation on the cellulose surface, and thus increased lignin inhibition. These results highlighted the validity of lignocellulosic films in elucidating inhibitions of cellulose enzymatic hydrolysis. The research could thus open a new avenue for the mechanistic study of the recalcitrance of lignocellulose to enzymatic hydrolysis.

Valorization of Arundo donax for the production of high performance lignocellulosic films

This work reports on the valorization of the biomass from the aquatic invasive species Arundo donax for the extraction of lignocellulosic fractions and the development of films with interest in food packaging. Stems and leaves were separately evaluated, with the stems producing higher yields and better properties for the extracted fractions.The purification of cellulose by removing hemicelluloses led to more crystalline and thermally stable fractions, which were more homogeneously dispersed in water and produced films with enhanced transparency, mechanical and water barrier properties.The application of a simplified extraction protocol, avoiding the use of organic solvents, led to the presence of minor amounts of lipidic impurities in the fractions, which, surprisingly, had a positive impact in the properties of the films. In particular, the film obtained from the purified cellulose without Soxhlet treatment (F3A) outperforms biopolymeric materials such as starch and PLA in terms of mechanical and water barrier performance.

Potential of lignocellulosic fractions from Posidonia oceanica to improve barrier and mechanical properties of bio-based packaging materials

This work reports on the valorization of residues from Posidonia oceanica leaves for the purpose of obtaining lignocellulosic fractions of interest for the development of bio-based materials for food packaging. The lignocellulosic fractions were characterized, thereby confirming the purification of cellulose and showing increases in crystallinity and thermal stability after the consecutive extraction steps. Subsequently, pure lignocellulosic films were obtained and characterized and the pure cellulose film showed the best properties in terms of mechanical performance and water vapor permeability. Finally, composite starch films containing lignocellulosic fractions were developed by melt compounding and characterized. Although the film containing the pure cellulose additive showed the optimum improvement in terms of mechanical properties (with an increase of 85% in the elastic modulus and 38% in the tensile strength), similar water vapor permeability reduction (~40%) was achieved with the least purified fractions, explained by their effect on starch gelatinization, as evidenced by SAXS/WAXS.

The effect of lignin on processing and the properties of lignocellulose material recovered by ionic liquid

As a prospective raw material, lignin containing papermaking fibers can be easily recycled, dissolved with proper solvents and reused. However, in order to utilize this material, more eco-friendly green dissolution methods are also required. As a green solvent, ionic liquids (ILs) have been attracted too much interest in processing of lignocellulosic biopolymers, but the practical effect of lignin on this process was not clear. In this due, production of lignocellulosic bio-composite films from bleached (lignin-free) and unbleached (lignin-containing) soda pulps was studied. First, fibers were dissolved in 1-Buthyl 3-Methyl Imidazolium Chloride (BMIMCL) at 85-95 °C. Following fabrication and preparation of the lignocellulosic films, certain mechanical and physical properties of cellulose composite films were analyzed. FESEM and XRD analytical methods were applied to study the product morphology and structure. Microscopic studies showed both fibers were disappeared in the ionic liquid in less than 1 h, although the unbleached fibers took more time for complete dissolution. The results indicated that the films produced from unbleached pulp had less tensile strength and more dynamic contact angle with water droplet than the ones produced from bleached pulp. Moreover, the optical tests revealed that the lignin resulted in less transparency of the films, but increased absorption of UV radiations. This implies that even impure lignocellulose feedstock can have promising features.

Controlled Assembly of Lignocellulosic Biomass Components and Properties of Reformed Materials

Reforming whole lignocellulosic biomass into value-added materials has yet to be achieved mainly due to the infusible nature of biomass and its recalcitrance to dissolve in common organic solvents. Recently, the solubility of biomass in ionic liquids (ILs) has been explored to develop all-lignocellulosic materials; however, efficient dissolution and therefore production of value-added materials with desired mechanical properties remain a challenge. This article presents an approach to producing high-performance lignocellulosic films from hybrid poplar wood. An autohydrolysis step that removes ≤50% of the hemicellulose fraction is performed to enhance biomass solvation in 1-ethyl-3-methyl imidazolium acetate ([C2mim][OAc]). The resulting biomass–IL solution is then cast into free-standing films using different coagulating solvents, yet preserving the polymeric nature of the biomass constituents. Methanol coagulated films exhibit a cocontinuous 3D-network structure with dispersed domains of less than 100 nm. The consolidated films with controllable morphology and structural order demonstrate tensile properties better than those of quasi-isotropic wood. The methods for producing these biomass derivatives have potential for fabricating novel green materials with superior performance from woody and grassy biomass.

Novel Approach to Prepare Ultrathin Lignocellulosic Film for Monitoring Enzymatic Hydrolysis Process by Quartz Crystal Microbalance

The applications of quartz crystal microbalance (QCM) rely heavily on the preparation of ultrathin films. So far, techniques on direct lignocellulosic film making without components isolation have been hardly investigated. In this work, a novel approach was developed to prepare spin-coated ultrathin films based on the complete dissolution of ball-milled wood in LiCl/DMSO solvent system. The surface analysis and elemental composition of the films respectively using atomic force microscopy and X-ray photoelectron spectroscopy proved that an even-textured lignocellulosic film could be formed on QCM gold sensors. The prepared ultrathin films were successfully applied on monitoring the enzymatic hydrolysis process in situ and in real time by QCM. The changes of QCM frequency showed clearly that the enzymatic hydrolysis of lignocellulosic materials could be divided into three stages, including cellulase adsorption, fast substrate hydrolysis, and slow substrate hydrolysis. The adsorption and hydrolysis processes...

Bioinspired lignocellulosic films to understand the mechanical properties of lignified plant cell walls at nanoscale

The physicochemical properties of plant fibres are determined by the fibre morphology and structural features of the cell wall, which is composed of three main layers that differ in chemical composition and architecture. This composition and hierarchical structure are responsible for many of the mechanical properties that are desirable for industrial applications. As interactions between the lignocellulosic polymers at the molecular level are the main factor governing the final cohesion and mechanical properties of plant fibres, atomic force microscopy (AFM) is well suited for the observation and measurement of their physical properties at nanoscale levels. Given the complexity of plant cell walls, we have developed a strategy based on lignocellulosic assemblies with increasing complexity to understand the influence of the different polymers on the nanomechanical properties. Measurements of the indentation moduli performed on one type of lignified cell wall compared with those performed on the corresponding lignocellulosic films clearly show the importance of the lignin in the mechanical properties of cell walls. Through this strategy, we envision a wide application of bioinspired systems in future studies of the physical properties of fibres.