Crystallinity Index Research Articles

Understanding the Role of Surface Chemistry in Nanocellulose Kink Formation: A Case Study of TEMPO-Mediated Oxidation.

This study found that the sources of cellulose have a significant effect on the parameters related to the kinks present in nanocellulose. During nanocellulose preparation, 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation induced partial depolymerization on whole cellulose and made the amorphous regions more susceptible to consequent mechanical treatment irrespective of cellulose sources. However, plant cellulose microfibrils were prone to break into shorter nanocellulose with fewer kinks, while bacterial and tunicate cellulose were more likely to bend rather than break, thus leading to the generation of more kinks. The kinks did not show significant effects on the size, crystallinity index, and thermal properties of nanocellulose for each cellulose source, though the kink numbers were positively related to the mechanical performance of nanocellulose. Collectively, this study elucidated the kink formation mechanisms and clarified the effects of kinks on nanocellulose performance, thus providing new insights into understanding the source and behaviors of microdefects present in nanocellulose.

Different metal-doped NiO nanoparticles for sunlight-mediated degradation of low-density polyethylene microplastic films.

Due to the widespread use and incorrect handling of plastics, we need to find a practical and effective way to eliminate plastic waste from the environment. Different metal-doped nickel oxide (DMD-NiO) nanoparticles (NPs) were synthesized using a sol-gel technique and were used to degrade low-density polyethylene (LDPE) microplastic (MP) films when exposed to sunlight. The optical and structural properties of sol-gel method synthesized materials were investigated using a variety of characterization methods (Fourier transform infrared (FT-IR), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), X-ray diffractometer (XRD) analysis, X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, and thermogravimetric analysis (TGA). Degradation study results suggest that the photocatalytic activity of DMD-NiO-LDPE nanocomposites (NCs) films was greater than that of pure LDPE and undoped NiO-LDPE films. Because of their increased optical absorption and efficient suppression of photo-produced charge carriers' recombination, the DMD-NiO NPs showed higher photocatalytic degradation of LDPE films. Thus, LDPE films with 2% wt Fe-NiO (iron-doped nickel oxide) nanomaterials showed a degradation of around 38.16% among DMD-NiO-LDPE NCs films under visible light over a short period of 30 days (240 h). The formation of carbonyl groups in the degradation product of LDPE was confirmed by Fourier transform infrared (FT-IR) analysis. When compared to the original LDPE film, the Fe-NiO-LDPE NCs films showed a significant decrease in crystallinity and carbonyl indexes, as much as 8.4% lower. The current project proposes the development of eco-friendly photocatalysts using a sol-gel technique for combating MP pollution in the environment.

Simple model to predict the intrinsic flexural modulus of abaca strands from crystallinity and microfibril angle

AbstractThis study presents a novel equation that obtains the intrinsic flexural modulus of a natural fiber from its microfibril angle (MFA) and its crystalline cellulose content, once having estimated both parameters from X‐ray diffraction (XRD). The percentage of crystalline cellulose was estimated as the content of cellulose times the crystallinity index. Moreover, the MFA of abaca strands was obtained through an equation relating MFA with the strain at break of the strands and by XRD azimuthal integration, obtaining similar results. Fully bio‐based composites, consisting of biopolyethylene reinforced with of abaca strands at 20 to 50 wt% contents, were tested to assess the impact of the natural fibers on the flexural modulus of the composites. The intrinsic flexural modulus was also evaluated by using three micromechanics models (Hirsh equation, Halpin and Tsai equation, and its modification by Nielsen). The values obtained from the application of the new equation, the micromechanics methods, and the literature showed satisfactory agreement.Highlights Evaluation of the flexural modulus of abaca strand reinforced bio‐polyethylene composites. Use of micromechanics models to obtain the intrinsic modulus of abaca strands. Formula that correlates the intrinsic flexural modulus of abaca to its crystalline cellulose content and microfibril angle.

Optimization of Microcrystalline Cellulose Production from Brewer’s Spent Grain by Acid Hydrolysis

Brewer’s spent grain (BSG) is the main insoluble solid by-product of the brewing industry. To add value to this non-wood material, microcrystalline cellulose (MCC) was prepared from BSG by alkaline pretreatment, bleaching, and subsequent acid hydrolysis to produce non-wood MCC. This study aimed to optimize MCC production using a statistical design (Box-Behnken) with three factors at three levels: acid concentration (0.5–1.5 M), hydrolysis time (70–90 min) and hydrolysis temperature (55–65 °C), to achieve the maximum yield and crystallinity of MCC derived from BSG. Results from 17 experimental runs revealed that the hydrolysis condition of 0.63 M HCl for 70 min at 61 °C yielded the highest output of 15% with a crystallinity index of 60%. The chemical structures and characteristics of MCC derived from BSG were verified by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction analysis (XRD). FT-IR analysis showed that the major wavenumbers of lignin and hemicellulose after the chemical processes (1500 cm–1 and 1735 cm–1) decreased by 21.40% and 4.60%, respectively. The XRD chromatogram revealed that the XRD characteristic peaks were sharper after the chemical treatments, indicating an increase in cellulose crystallinity due to removing lignin and hemicellulose. The crystallinity index of MCC derived from BSG ranged from 55–64%, which is comparable in quality to commercial pharmaceutical MCC, Avicel® PH-101 (67.37%). These results demonstrated that MCC from BSG was successfully prepared by acid hydrolysis under optimized conditions. BSG proved a viable non-wood source for preparing MCC for application in the pharmaceutical and nutraceutical industries.

Reinforcing polyvinyl alcohol films with layered double hydroxide and tannic acid to enhance tensile strength, tribological performance, and corrosion resistance in biomedical coating applications

Abstract This study investigates the synergistic effects of incorporating layered double hydroxide (LDH) and tannic acid (TA) into polyvinyl alcohol (PVA) films to enhance their mechanical, tribological, and corrosion resistance properties for biomedical applications. Composite coating films were prepared by blending PVA with LDH and TA in various concentrations. The addition of LDH and TA significantly increased the crystallinity index of the composite films, with the highest crystallinity observed at 66.3% for the sample containing 1 wt% TA and 2 wt% LDH (PVA/TA1/LDH2). This enhancement in crystallinity contributed to improved mechanical performance, as demonstrated by tensile tests, where the PVA/TA1/LDH2 composite exhibited the highest tensile strength among all samples. Tribological testing revealed that the PVA/TA1/LDH2 composite also achieved the lowest coefficient of friction (COF), along with a minimal wear rate, indicating superior wear resistance. SEM analysis of the wear scars confirmed a narrow wear track and smoother surface morphology for this composite, which suggests effective load distribution and reduced surface degradation. The addition of TA was further shown to improve the corrosion resistance of the PVA composite films, with the PVA/TA1/LDH1 sample exhibiting the lowest corrosion current density (Icorr) of 0.36 µA cm⁻², representing a significant improvement over neat PVA. These findings highlight the potential of PVA/LDH/TA films for coating applications in biomedical devices, where enhanced mechanical strength, wear resistance, and corrosion protection are critical. The synergistic effects of LDH and TA provide a pathway for developing durable and functional coatings, expanding the practical utility of PVA films in demanding biomedical environments.

Paclitaxel loaded Capmul MCM and tristearin based nanostructured lipid carriers (NLCs) for glioblastoma treatment: screening of formulation components by quality by design (QbD) approach.

Paclitaxel (PTX), a naturally occurring diterpenoid isolated from Taxus brevifolia, is a first-line drug for the treatment of glioblastoma; however, it suffers from the disadvantages of poor water solubility and nonspecific biodistribution, which cause serious side effects in the human body. The marketed formulation suffers from serious side effects, such as allergic reactions, neutropenia, and neuropathy, which require safe and effective formulations of PTX. In the present study, PTX was entrapped in a solid-liquid lipid mixture with the aid of a surfactant using a modified solvent evaporation technique. Higher entrapment of the impressive stability of the formulation was achieved by employing quality design-based strategies. Optimized levels by employing a numerical optimization technique for each factor, that is, surfactant concentration (X1), lipid concentration (X2), and amount of organic solvent (X3) were 0.3%, 0.76% & 8.3 ml respectively. The resultant formulation exhibited a particle size of 121.44 nm, entrapment efficiency of 94.27%, and zeta potential of -20.21 mV with unimodal size distribution. A reduction in the % crystalline index from 48 to 3.4% ensured the amorphous form of the entrapped drug inside the formulation, which precludes the fear of leakage and instability of the formulation. Cell line studies conducted on U87MG Cell lines also suggested that the NLC of paclitaxel are more effective than those of pure PTX. In summary, PTXNLC seem to be a superior alternative carrier system for the formulation industry to obtain higher entrapment with excellent stability.

The influence of plasticizer on the mechanical, structural, thermal and strain recovery properties following stress-relaxation process of silk fibroin/sodium alginate biocomposites for biomedical applications

The influence of plasticizer glycerol (GLY) on the mechanical, structural, and thermal properties of silk fibroin (SF)/sodium alginate (SA) biocomposite films was investigated in detail. As the SF/SA ratio increased up to 65%, the SF content significantly improved the Tensile strength (σT), Young's modulus (Ey) but reduced the elongation at break (εb). To modify and enhance the elasticity and flexibility of the biocomposite films, the GLY as a plasticizer was used at different ratio from 20 to 50% for each SF/SA biocomposite films. Although the extensibility of the films was improved greatly with increasing GLY ratio, σT and Ey reduced significantly. The effect was observed more apparently for the GLY ratio starting from 35%. It was also shown that crystallinity index in the Amide I region increased as the SF/SA ratio increased to 65%. Increasing SF content improved the thermal stability of the SF/SA biocomposites. The XRD results showed that crystallinity was increased as SF/SA ratio increased. Stress-relaxation of SF/SA (30%) biocomposite films plasticized with GLY revealed that each kind of plasticized films showed a viscoelastic behavior and a fast relaxation in the first stage (1–2 min) of the processes and then continued slowly. The GLY increased the extensibility and elasticity limit of the SF/SA (30%) composite films. During the strain recovery processes, the plasticized composite films recovered completely in a quite shorter time than that of unplasticized films. It was observed higher the GLY content, the recovery times became shorter.

Crystallographic Characterization of Gypsum Synthesized from Marine Wastes: Babylonia japonica, Olive sayana, and Conasprella bermudensis

The study synthesized gypsum nanocrystals using conventional wet chemical precipitation methods from marine mollusks like Babylonia Japonica, Olive Sayana, and Conasprella bermudensis. Different characterization techniques like Thermogravimetric Analysis (TGA), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDX) were used to confirm the formation of the nanocrystals. XRD data assessed various structural parameters, including the dimension of the unit cell, crystallinity index, specific surface area, lattice parameters, dislocation density, and macrostrain. The Rietveld refinement study did not reveal the formation of alternate phases, and the predicted lattice parameters, Full Width at Half Maximum (FWHM), and X-ray density contradicted the actual data. The synthesized gypsum displays crystallite dimension within the acceptable range of < 200 nm, as calculated using various XRD model equations. Additionally, the values for strain (2× 10-4 to 4 × 10-4), stress (-1×107 to 2×107 N/m2), and energy density (2.87 × 102 to 2.16× 103 J/m3) were also estimated for the synthesized samples. The preferential growth calculation indicates stable phase formation of gypsum along the (020) and (040) plane. Furthermore, The study compared the properties of gypsum, including pH, conductivity, and potential difference (PD), in soil extraction and an aqueous medium.

Isolation and characterization of biomass waste based bioplasticizer from Eucalyptus leaf: A suitability analysis of biofiller for polymeric composites

Plasticizers improve polymeric materials' properties and processability as additives. Currently, a variety of liquid synthetic plasticizers derived from fossil fuels are available. The environmental unsuitability of these materials could potentially lead to adverse effects on the environment. When we compare solid and liquid plasticizers, we find an infinite variety of liquid plasticizers. As a result, our work focuses on the extraction of plasticizer from plant sources. Accordingly, the plasticizer is extracted from eucalyptus leaves via solvent purification and surface catalysis. Research was conducted utilizing X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Ultraviolet (UV) visible spectroscopy to determine the characteristics of plasticizer. The scanning electron microscopy (SEM) and energy dispersive spectrum (EDS) analysis are used to analyze the surface morphology of the isolated plasticizer. The plasticizer's UV examination reveals active absorption at 375.21 nm. The plasticizer was determined to have a lower density of 0.941 g/cm3. The plasticizer that was extracted had a low solubility in water and organic solvents while possessing an estimated molecular weight of 340. The glass transition temperature of plasticizer was also examined using differential scanning electron microscopy analysis and found to be 64.17°C. The crystallinity index and size were found to be 34.08% and 28.57 nm, respectively. The characteristic features obtained were well-suited for use as filler in polymer composite materials.

Unveiling the untapped potential of Hibiscus Rosa-sinensis lignocellulosic fiber: A multifaceted characterization for advancing sustainable biocomposite applications

In the pursuit of sustainable advancements in bio-inspired fiber reinforced polymer composite materials, the exploration of novel natural fibers has become a focal point of research. This experimental study aims to elucidate the unexplored potential of Hibiscus Rosa-sinensis fiber (HRF) as a versatile reinforcement material for high-performance composites. Through an integrated approach, this research offers a meticulous analysis of the HRF's physico-chemical properties, and single fiber tensile strength. The crystalline structure are revealed by X-ray diffraction (XRD), thermal behavior are characterized through thermo-gravimetric analysis (TGA), and surface morphology has been visualized using field emission scanning electron microscopy (FESEM) studies. From the results, it is found that the HRF contains a cellulose content of 79.50 %, positioning it as a prime bast fiber among its counterparts. This composition is complemented by hemicellulose (10.36 %), lignin (4.62 %), wax (0.84 %), and ash (2.96 %). The Fourier-transform infrared spectroscopy (FTIR) spectra unveils the intricate functional groups present in the fibers. XRD analysis highlights a crystallinity index (CI) of 66.93 %, confirming a well-organized and structured crystalline arrangement. The thermal stability established through TGA underscores HRF's resilience up to 284 °C, presenting it is an optimal reinforcement material for bio-inspired green composites operating within 280 °C. The surface morphology of HRF is examined through FESEM and three-dimensional profiling, showcasing its inherent morphological intricacies. The multidimensional characterization provided herein contributes significantly to the evolving landscape of biocomposite research, fostering a platform for future advancements and innovations in HRF-based composite materials.

Spatial heterogeneity of sediments on a topographically diverse descending plate at convergent margins: An example from the outer slope of the Mariana Trench

Unraveling deep ocean sediment composition and its controlling mechanisms is crucial to understanding the interplay between the Earth's surface and the deep Earth. Convergent margins are generally featured by various seafloor landforms, but how submarine topography affects sediment accumulation processes remains poorly understood. Here we focus on submarine surface sediments from the outer slope of the Mariana Trench (covering water depths of 1218–6310 m) and combine microscopic observation, clay mineralogy, and elemental geochemistry to characterize sediment composition and to reveal physical, chemical, and biological sedimentary processes at topographically diverse convergent margins. Smear slide observations indicate that foraminifera shells dominate in shallow areas, while pelagic clays and diatom oozes prevail in trench and slope areas. Clay minerals primarily consist of illite (26–98 %) with low crystallinity index values and diverse chemical index values, followed by chlorite (0–45 %) and kaolinite (0–29 %). Smectite (0–61 %, 46 of 70 samples have smectite contents <5 %) of the samples from the outer slope area is low but appears dominant close to the trench. Bulk element compositions are mainly affected by the relative calcareous, siliceous, and lithogenous components that dissolved or accumulated inconsistently as submarine topographic feature changes. Our results imply that submarine topography and sediment provenance lead to significant heterogeneity of sediment composition at topographically diverse convergent margins. The submarine topographic relief, together with associated bathymetry and deep-sea circulation primarily controls carbonate deposition on the Caroline Plateau, and influences the sinking particles (including diatom shells and arc volcanic-sourced materials) accumulation in the trench basin. Continent-derived aeolian dust introduces illite-rich detritus, while localized volcanism potentially contributes to smectite-rich sediment in certain topographic provinces. We propose that the deep sea sedimentation processes in the Mariana convergent system are more diverse and complex than those at the margins with relatively plain topographic characteristics (e.g., the Japan Trench). The significant heterogeneity on descending plates along convergent margins may lead to various subduction behaviors. These findings contribute to a better understanding of deep ocean sediment source-to-sink systems and have implications for Earth's material cycle and multi-sphere interaction studies.

A holocellulose air filter with highly efficient formaldehyde adsorption prepared via low temperature pulping and partial dissolving from corn stalks

Emissions of particulate matter (PM) originating from industrial and agricultural incineration had emerged as a significant public health concern. Furthermore, the considerable annual production of straw remains underutilized, particularly in China. In this study, we proposed a novel approach for holocellulose air filter production from corn stalks via low-temperature anthraquinone pulping, partial dissolving, and high-speed shear-induced regeneration. About 61.40–78.23 % of hemicellulose in corn stalks was retained in holocellulose, furthermore, the delignification rate was up to 81.63–92.51 % after low temperature (<100 °C) alkaline exactment. Subsequently, holocellulose air filters (RHF) was prepared through regeneration with high-speed shear induced (25,000 rpm) and freeze-drying. The final air filters contained approximately 8.56–12.4 % hemicellulose, exhibiting a substantial adsorption capacity for low molecules such as formaldehyde. The results revealed remarkably low PM2.5 penetration ratio (0.12 %) and pressure drop (14.3 Pa) of the air filter, while exhibiting a remarkable formaldehyde adsorption capacity of 54.5 mg/g. Moreover, the characters of high crystallinity index and robust micro/nano-structure of regenerated cellulose were obtained. This study introduced an innovative and facile strategy for gaseous formaldehyde adsorption and introduced novel solutions for agricultural waste utilization.

Bacterial nanocellulose production: Improvement in productivity and properties via a sustainable medium

High production cost is a significant barrier to commercial bacterial nanocellulose (BNC) production. This study addresses this issue using a low-cost molasses and cheese whey medium via Gluconacetobacter hansenii. The one-factor-at-a-time method investigated the effect of critical factors on BNC production, including total sugar and total protein concentrations (g/L), initial pH, and additives such as ethanol and acetic acid (%(v/v)). The productivity in the HS medium was 0.125 g/L/day, while the low-cost medium without additives achieved a productivity of 0.5275 g/L/day. Although the addition of ethanol decreased the productivity, the inclusion of 0.4 %(v/v) acetic acid increased the productivity to 0.64 g/L/day. Using the low-cost medium with acetic acid led to a 40-fold reduction in production costs compared to the HS medium. Furthermore, transitioning from HS media to the low-cost medium resulted in BNC with thicker fibres, a higher crystallinity index (%) and improved mechanical properties. The ratio of Iα/ Iβ in BNC produced in HS media decreased from 1.68 to 1.09 in the low-cost medium. The thermal properties of BNC produced in the low-cost medium also showed slight improvements compared to those in the HS medium. The degree of polymerization significantly increased from 1096 to 1457 in the low-cost medium compared to HS media. These findings highlight the potential of using a low-cost medium to produce BNC with enhanced properties, offering a sustainable and cost-effective alternative to conventional plastics.

Advancing bamboo fiber reinforcement: A novel approach using eco-friendly plant ash alkali treatment.

This study aimed to enhance the engineering performance of bamboo fibers for use in composite materials by employing a sustainable plant ash alkali treatment. The primary objective was to improve the tensile strength, crystallinity, and thermal stability of bamboo fibers, which are known for their high specific strength, low density, and biodegradability but suffer from poor compatibility with hydrophobic matrices. The study involved treating bamboo fibers with varying concentrations of plant ash solutions (5 %, 10 %, 20 %, and 30 % by mass fraction) and comparing the results with those from conventional NaOH treatment. The results showed that plant ash treatment at a 20 % concentration significantly improved tensile strength by 14.16 % compared to untreated fibers, increased the crystallinity index to 75.57 %, and enhanced thermal stability, retaining more residual mass at high temperatures than NaOH-treated fibers. These improvements are attributed to the reduction in fiber polarity and better preservation of fiber structure. The findings suggest that plant ash, as a cost-effective and eco-friendly alternative to NaOH, can significantly enhance the mechanical and thermal properties of bamboo fibers, making them suitable for use in environmentally sustainable composite materials in construction, and other industries.

Optical Studies of Silver Oxide Deposited Thin Films Using the RF Sputtering Technique

Background/Objectives: Silver Oxide is an efficient material because it is used in batteries. Apart from this, it is a moderate oxidizing agent in a variety of processes including the oxidation of aldehydes to carboxylic acids. The objective of the study is to synthesize silver oxide films by RF sputtering technique so that synthesized films can be inserted in the spectrophotometer for optical study. Methods: Silver Oxide films were deposited on Fluorine-doped Tin Oxide (FTO) glass using Radio Frequency (RF) sputtering method and annealed at 200 °C, for two hours, and then it was used in DK2 Ratio recording Spectrophotometer to analyze absorption and transmission data. Findings: The thickness of the films was measured using a non-contact optical Profilometer, in the range of (42– 660) nm. The films were subsequently exposed to optical characterization, revealing exceptionally low transmittance and high absorbance. The band gap is estimated to be 2.2 eV. The X-ray diffraction (XRD) studies reveal that the material is crystalline and Miller indices have also been determined. The morphology and topography of the thin films were analyzed using Field Emission Scanning Electron Microscope (FESEM) and the chemical composition was estimated using EDS. Novelty: The present work reveals that the optical properties are highly dependent on the thickness and the material distribution. The direct band gap energy is evaluated from the absorption spectrum which comes out to be 2.2 eV. The XRD spectra synthesized Silver Oxide films are crystalline in nature. Keywords: Silver Oxide, Band gap, XRD, FESEM

Performance analysis of biodegradable composite using polyvinyl alcohol and pomegranate peel powder for sustainable dry packaging applications

This study focuses on the fabrication of a biodegradable dry packaging material for fruits, vegetables, and flowers, with an emphasis on affordability for street vendors. Approximately 55% of waste originates from packaging materials. To address this issue, a biodegradable Polyvinyl alcohol/Pomegranate peel powder (PVA/PPP) composite film was fabricated. The PVA, a water-soluble synthetic biodegradable polymer, served as the matrix, while PPP, an agro-waste product, was used as the filler. The PVA/PPP films were characterized through optical microscopy, FTIR, XRD, TGA, DSC, moisture absorption analysis, water vapour transmission rate (WVTR), water vapour permeability (WVP), and oxygen permeability testing. The inclusion of PPP enhanced the film’s properties via increasing moisture absorption by 85%, reducing PVA crystallinity index from 33.2 to 17.5%, percentage crystallinity reduced from 73.90 to 0.57%, lowering WVTR from 0.063 to 0.042 g/h.m2, low oxygen permeability and improving thermal stability up to 423 °C. Additionally, the pH of PPP (4.5) contributed to microbial resistance. The fabricated PVA/PPP films were fully biodegradable and produced via green synthesis without any hazardous chemicals. The use of PPP as a filler not only improved film performance but also reduced environmental hazard, demonstrating the material’s suitability for sustainable packaging applications.

Integrated formic acid and deep eutectic solvent mediated sustainable synthesis of cellulose nanocrystals from Sterculia foetida shells

The present study reports the green synthesis of cellulose nanocrystals from the shells of Sterculia foetida (SFS) cellulose. Three different methods, alkali, acid and organic acid, were screened for the maximum cellulose extraction. A maximum cellulose yield, 30.6 ± 0.84 w/w, was obtained using 90% formic acid at 110 °C in 120 min. The extracted cellulose was characterized and identified by instrumental analyses. SEM analysis showed skeletal rod-like microfibril structures and similar intra-fibrillar widths. CP/MAS 13C NMR and FTIR spectrum revealed the purity of cellulose and the absence of other components like hemicellulose and lignin. XRD study revealed a cellulose crystallinity index of 88.07%. BET analysis showed a good surface area (3.3213 m2/g) and a micro-pore area of 1.871 m2/g. The cellulose nanocrystals were synthesized from the extracted cellulose using deep eutectic solvents (DES), choline chloride and lactic acid (1:2 ratio). The cellulose nanocrystals (CNC) synthesized from DES-based exhibited zeta potential and particle size of −16.7 mV and 576.3 d.nm. DES-synthesized cellulose nanocrystals were spherical-like shapes, as observed from TEM images. The present results exposed that formic acid is an effective and green catalyst for the extraction of cellulose and DES for the sustainable synthesis of CNC.

Microwave-associated ZnCl2 pretreatment followed by enzymatic hydrolysis for high-efficiency production of nanocellulose from Eucalyptus dissolving pulp

Herein, we developed a novel microwave-associated ZnCl2 pretreatment followed by enzymatic hydrolysis for high-efficiency and environmentally friendly production of nanocellulose. With a short pretreatment time (60 s), nanocellulose was yielded with a high overall yield of 87.99 % from Eucalyptus Dissolving Pulp (EDP). Characterization analysis revealed that microwave-associated ZnCl2 pretreatment can efficiently swollen the structure of EDP, and after enzymatic hydrolysis, the nanocellulose in spherical shape was formed with abundant functional groups, low crystalline index, and poor thermal stability. By Energy Dispersive X-Ray Spectroscopy (EDS) and inductively coupled plasma mass spectrometry (ICP-MS) analysis, approximately 20 wt% of zinc distributed on the surface and in the interior of cellulose, that may lead to the low Zeta potential of the nanocellulose and the formation of nanospheres. Furthermore, through optimization of the pretreatment process, it was feasible to increase the solid concentration of EDP to 3 wt% while concurrently reducing the ZnCl2 concentration to 0.1 mol (ZnCl2·9H2O). Under this condition, ultrafine cellulose nanocrystals (CNC) and cellulose nanofiber (CNF)/CNC blend were produced with an outstanding yield of 93.3 %. Moreover, the recyclability of ZnCl2 post-pretreatment was demonstrated, as ZnCl2 could be efficiently reused for subsequent pretreatment cycles. Notably, even after five cycles of recycling, the nanocellulose yield remained consistently above 90 %. Overall, this study highlights the viability and sustainability of microwave-assisted ZnCl2 pretreatment for efficient nanocellulose production, offering a sustainable and cost-effective route for industrial-scale applications.

Production and characterization of bacterial cellulose synthesized by Enterobacter chuandaensis strain AEC using Phoenix dactylifera and Musa acuminata.

Bacterial cellulose (BC) is a biopolymer synthesized extracellularly by certain bacteria through the polymerization of glucose monomers. This study aimed to produce BC using Enterobacter chuandaensis with fruit extracts from Phoenix dactylifera (D) and Musa acuminata (M) as carbon sources. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) showed characteristic cellulose vibrations, while X-ray diffraction (XRD) identified distinct peaks at 15.34°, 19.98°, 22.58°, and 34.6°, confirming the cellulose structure. Whole-genome sequencing of E. chuandaensis identified key genes involved in BC production. The BC produced then exhibited a molecular weight of 1,857,804g/mol, with yields of 2.8g/L and 2.5g/L for treatments D and M, respectively. The crystallinity index of the purified BC was 74.1, and 13C NMR analysis confirmed the dominant cellulose Iα crystalline form. The BC showed high biocompatibility in cytotoxicity assays, with cell viability between 92% and 100%, indicating its potential for use in biomedical applications. This investigation represents the first report of BC production by E. chuandaensis, which promises a new avenue for sustainable and efficient BC synthesis using fruit extracts as carbon sources.

Isolation and Characterization of Novel Cellulose Micro/Nanofibers from Lygeum spartum Through a Chemo-Mechanical Process.

Recent studies have focused on the development of bio-based products from sustainable resources using green extraction approaches, especially nanocellulose, an emerging nanoparticle with impressive properties and multiple applications. Despite the various sources of cellulose nanofibers, the search for alternative resources that replace wood, such as Lygeum spartum, a fast-growing Mediterranean plant, is crucial. It has not been previously investigated as a potential source of nanocellulose. This study investigates the extraction of novel cellulose micro/nanofibers from Lygeum spartum using a two-step method, including both alkali and mechanical treatment as post-treatment with ultrasound, as well as homogenization using water and dilute alkali solution as a solvent. To determine the structural properties of CNFs, a series of characterization techniques was applied. A significant correlation was observed between the Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) results. The FTIR results revealed the elimination of amorphous regions and an increase in the energy of the H-bonding modes, while the XRD results showed that the crystal structure of micro/nanofibers was preserved during the process. In addition, they indicated an increase in the crystallinity index obtained with both methods (deconvolution and Segal). Thermal analysis based on thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) confirmed improvement in the thermal properties of the isolated micro/nanofibers. The temperatures of maximum degradation were 335 °C and 347 °C. Morphological analysis using a scanning electron microscope (SEM) and atomic force microscope (AFM) showed the formation of fibers along the axis, with rough and porous surfaces. The findings indicate the potential of Lygeum spartum as a source for producing high-quality micro/nanofibers. A future direction of study is to use the cellulose micro/nanofibers as additives in recycled paper and to evaluate the mechanical properties of the paper sheets, as well as investigate their use in smart paper.