Cellulose Nanocrystals Research Articles

Interface interactions driven antioxidant properties in olive leaf extract/cellulose nanocrystals/poly(butylene adipate-co-terephthalate) biomaterials

Functional packaging represents a new frontier for research on food packaging materials. In this context, adding antioxidant properties to packaging films is of interest. In this study, poly(butylene adipate-co-terephthalate) (PBAT) and olive leaf extract (OLE) have been melt-compounded to obtain novel biomaterials suitable for applications which would benefit from the antioxidant activity. The effect of cellulose nanocrystals (CNC) on the PBAT/OLE system was investigated, considering the interface interactions between PBAT/OLE and OLE/CNC. The biomaterials' physical and antioxidant properties were characterized. Morphological analysis corroborates the full miscibility between OLE and PBAT and that OLE favours CNC dispersion into the polymer matrix. Tensile tests show a stable plasticizer effect of OLE for a month in line with good interface PBAT/OLE interactions. Simulant food tests indicate a delay of OLE release from the 20 wt% OLE-based materials. Antioxidant activity tests prove the antioxidant effect of OLE depending on the released polyphenols, prolonged in the system at 20 wt% of OLE. Fluorescence spectroscopy demonstrates the nature of the non-covalent PBAT/OLE interphase interactions in π-π stacking bonds. The presence of CNC in the biomaterials leads to strong hydrogen bonding interactions between CNC and OLE, accelerating OLE released from the PBAT matrix.

RETRACTED: Green and efficient synthesis of cellulose nanocrystals from Hamelia patens leftover via hydrolysis of microwave assisted-ionic liquid (MWAIL) pretreated microcrystalline cellulose

The efficient bioconversion of the lignocellulosic agro-waste has immense importance in biorefinery processing in extracting the cellulose and saccharide fractions. To achieve this, a series of chemical pretreatments is employed, thus concerning environmental threats limit its use. Therefore, an ionic liquid is employed for pretreatment before sustainable extractions owing to its safe manipulation, recycling, and reusability. Specifically, microwave-assisted ionic liquid (MWAIL) pretreatment has significant importance in extracting high cellulose yield at less thermal power consumption. In this study, the leftover stalks of Hamelia patens were subjected to MWAIL pretreatment at 60, 70, 80, and 90 °C to extract microcrystalline cellulose (MCC). Subsequently, the MCC was fabricated into cellulose nanocrystals (CNC) through hydrolytic treatment using acidic and ionic liquids and denoted as CNC-AH and CNC-ILH. Thus obtained CNC was characterized by FTIR, FESEM, XRD, and TGA to investigate the influence of solvent on its morphology, crystallinity, and thermal stability of CNC. The results support that the CNC-ILH has comparatively more thermal and dispersal stability with a reduced crystallinity index than CNC-AH. The surprising results of CNC-ILH signify its utilization in diverse applications in the food and industrial sectors.

Enhancing chondrogenic differentiation of mesenchymal stem cells through synergistic effects of cellulose nanocrystals and plastic compression in collagen-based hydrogel for cartilage formation

Collagen-based (COL) hydrogels could be a promising treatment option for injuries to the articular cartilage (AC) becuase of their similarity to AC native extra extracellular matrix. However, the high hydration of COL hydrogels poses challenges for AC's mechanical properties. To address this, we developed a hydrogel platform that incorporating cellulose nanocrystals (CNCs) within COL and followed by plastic compression (PC) procedure to expel the excessive fluid out. This approach significantly improved the mechanical properties of the hydrogels and enhanced the chondrogenic differentiation of mesenchymal stem cells (MSCs). Radially confined PC resulted in higher collagen fibrillar densities together with reducing fibril-fibril distances. Compressed hydrogels containing CNCs exhibited the highest compressive modulus and toughness. MSCs encapsulated in these hydrogels were initially affected by PC, but their viability improved after 7 days. Furthermore, the morphology of the cells and their secretion of glycosaminoglycans (GAGs) were positively influenced by the compressed COL-CNC hydrogel. Our findings shed light on the combined effects of PC and CNCs in improving the physical and mechanical properties of COL and their role in promoting chondrogenesis.

Characterization and isolation method of Gigantochloa scortechinii (Buluh Semantan) cellulose nanocrystals

This study explored the impact of sodium hydroxide and benzoylation treatment on the production of cellulose nanocrystals from Semantan bamboo (Gigantochloa scortechinii). Bamboo cellulose nanocrystals (BCNs) were obtained via acid hydrolysis, with the effectiveness of an isolation method and chemical treatments demonstrated in removing non-cellulosic constituents. X-ray diffraction analysis revealed a crystalline cellulose II structure for benzoylated BCN (B) and a crystalline cellulose I structure for NaOH-treated BCN (S), with BCN (S) exhibiting a higher crystallinity index (80.55 %) compared to BCN (B) (67.87 %). The yield of BCN (B) (23.68 ± 1.10 %) was higher than BCN (S) (20.65 ± 2.21 %). Transmission electron microscopy images showed a mean diameter of 7.95 ± 2.79 nm for BCN (S) and 9.22 ± 3.38 nm for BCN (B). Thermogravimetric analysis indicated lower thermal stability for BCN (B) compared to BCN (S), with charcoal residues at 600 °C of 31.06 % and 22 %, respectively. Zeta potential values were −41.60 ± 1.97 mV for BCN (S) and −21.80 ± 2.54 mV for BCN (B). Gigantochloa scortechinii holds significant potential for sustainable and eco-friendly applications in the construction, furniture, and renewable energy industries. These findings highlight the versatility and potential of BCNs derived from Gigantochloa scortechinii for various applications.

Insights into contrastive cellulose nanofibrils assembly and nanocrystals catalysis from dual regulations of plant cell walls

Insights into contrastive cellulose nanofibrils assembly and nanocrystals catalysis from dual regulations of plant cell walls

Facile preparation of highly adhesive yet ultra-strong poly (vinyl alcohol)/cellulose nanocrystals composite hydrogel enabled by multiple networks structure

Poly (vinyl alcohol) (PVA) hydrogel showed potential applications in bioengineering and wearable sensors fields. It is still a huge challenge to prepare highly adhesive yet strong poly (vinyl alcohol) hydrogel with good biocompatibility. Herein, we prepared a highly self-adhesive and strong poly (vinyl alcohol)/tannic acid@cellulose nanocrystals (PVA/TA@CNCs) composite hydrogel using TA@CNCs as functional nanofiller via facile freezing-thawing method. Multiple networks consisting of hydrogen bonding and coordination interactions endowed the hydrogel with high mechanical strength, excellent flexibility and fracture toughness with adequate energy dissipation mechanism and relatively dense network structure. The tensile strength of PVA/TA@CNCs hydrogel reached the maximum of 463 kPa, increasing by 367 % in comparison with pure PVA hydrogel (99 kPa), demonstrating the synergistic reinforcing and toughening effect of TA@CNCs. The hydrogel exhibited extremely high adhesion not only for various dry and wet substrates such as plastic, metal, Teflon, rubber, glass, leaf, but also sweaty human skin, showing good adhesion durability. The highest adhesion strength to silicone rubber, steel plate and pigskin could reach 197 kPa, 100 kPa and 46.9 kPa, respectively. Meanwhile the hydrogel had negligible cytotoxicity to cells and showed good biocompatibility.

In‐situ preparation and performance of cellulose nanocrystals grafted with polyamide 6 composites

AbstractNylon nanocomposites were prepared by in‐situ ring‐opening polymerization to overcome the problem of poor properties due to the uneven dispersion of the nanoparticles by the traditional melt blending. This high‐performance polyamide 6 (PA6) nanocomposites with high dispersion and strong interface was prepared by grafting PA6 onto the surface of cellulose nanocrystals (CNC). The micromorphology, mechanical, crystalline and thermal properties of the composites were also investigated. Firstly, the hydroxyl group on the surface of CNC reacted with the para isocyanate of toluene diisocyanate (TDI), and the remaining ortho isocyanate was blocked by caprolactam to prepare CNC grafted with caprolactam (CNC‐g‐CL). Then CNC‐g‐CL was used as an activator to prepare cellulose nanocrystal grafted with polyamide 6 (CNC‐g‐PA6) composites by the ring‐opening polymerization of caprolactam on the CNC. The effects of different reaction temperatures, solvent amounts and molar ratios on the grafting rate of CNC‐g‐CL were investigated. The results showed that the highest grafting rate of CNC‐g‐CL with 66.7% was achieved at a reaction temperature of 45°C, 0.1 g/mL CNC in toluene, and a molar ratio of 6 for TDI/CNC. Further, different CNC‐g‐PA6 composites prepared from different CNC content and activator content were explored. For CNC‐g‐PA6 composites, CNC was uniformly dispersed in the PA6 matrix and had a good compatibility with the matrix. CNC exhibited significant reinforcement in the composites with a tensile strength of up to 108 MPa. In addition, the glass transition temperature of CNC‐g‐PA6 was increased to 92°C, which significantly improved the heat resistance of the new composites.Highlights Effects of reaction condition of CNC and TDI on DSTDI and DSCL were studied. Effects of CNC and activator content on CNC‐g‐PA6 properties were studied. CNC is uniformly dispersed in PA6 with average particle size less than 1 micron. The nylon matrix was significantly strengthened by the addition of CNC. The addition of CNC significantly improved the heat resistance of the composites.

Evaluating the reinforcing potential of enzymatic cellulose nanocrystals in polypropylene nanocomposite

Cellulose nanocrystals (CNCs) produced through enzymatic hydrolysis exhibit physicochemical properties that make them attractive as eco-friendly reinforcing agents in polymer composites. However, the extent of their efficacy within a polymeric matrix is yet to be fully established. This study investigated the reinforcing capabilities of enzymatic CNC (approximately 3 nm in diameter) isolated from bleached eucalyptus Kraft pulp (BEKP), focusing on its application in polypropylene (PP) nanocomposites produced by injection molding. The study compared the performance of this enzymatic CNC (1–5 % wt) with PP composites reinforced with micro-sized cellulose fibers (BEKP at 10–30 % wt, approximately 13 μm) and additionally with commercial CNC produced by sulfuric acid hydrolysis. Despite enzymatic CNC experiencing agglomeration during spray-drying, leading to an average diameter increase to 3 μm, it still significantly increased the crystallization and glass transition temperature of the PP matrix. However, this agglomeration likely hindered the improvement of the mechanical properties within the nanocomposites. The results also showed that enzymatic CNC provided higher thermal stability at lower reinforcement levels compared to BEKP, but this came with a reduction in stiffness, posing a significant consideration in composite design. The addition of a coupling agent greatly enhanced the dispersion of reinforcements and the interfacial adhesion within the matrix, contributing to the enhanced performance of the composite properties. Additionally, enzymatic CNC demonstrated potential for superior reinforcement efficacy compared to commercially available CNC produced by sulfuric acid hydrolysis. In conclusion, enzymatic CNC exhibited a promising role as nano-reinforcement for thermoplastic polymer nanocomposites, exhibiting higher thermal properties at lower reinforcing loads than traditional micro-sized fiber reinforcements. The absence of sulfur, coupled with its higher thermal stability and sustainable potential, positions enzymatic CNC as a particularly favorable choice for applications involving direct contact with food, cosmetics, pharmaceuticals, and biomedical materials.

Synthesis and characterization of bio‐based poly(urethane‐urea) nanocomposite coatings employing cellulose nanocrystals incorporated by two different routes

AbstractDuring the last decades, the interest in the development of materials fully or partially biobased has increased. Polyurethanes are extensively used in a wide range of industries because of their versatility. The present work explores the synthesis of partially biobased poly(urethane‐urea) (PUU) composites employing soy‐based polyol (SPO) and cellulose nanocrystals (CNC). The latter were incorporated during the synthesis (in‐situ) or after the synthesis (ex‐situ). The possibility of a technological application as coatings was investigated for the designed materials. Polycaprolactone diol was used as a soft segment due to high functionality of the soy‐based polyol. The physicochemical, thermal and mechanical properties of the prepared matrices were analyzed. Poly(urethane‐urea)s containing up to 20% by weight of biobased polyol showed coating application potentiality. Compared to a polycaprolactone‐based polyurethane, the utilization of the bioprecursor enhanced light absorption in the UV–Vis region. In addition, partially biobased systems showed better mechanical resistance (Young's modulus increased up to 6 times) and hydrophobicity (sweeling decreased from 60 to 8 per cent by weight). Incorporation of cellulose nanocrystals affected primarily the physicochemical and rheological properties of dispersions. Regarding coating properties, nanocrystals utilization complemented the soy‐based polyol improving the performance of the films. Furthermore, the incorporation route affected the dispersions and films properties.Highlights SPO was incorporated up to 20 per cent by weight in PUU composites. Higher SPO contents improved UV–Vis absorption and tensile strength of films. Films were less hydrophilic as more SPO was incorporated. The CNC‐reinforcement was complementary to the utilization of the SPO. CNC incorporation route affects properties and performance of the coatings.

A simple and high-performance cellulose nanocrystal based biocatalytic Pickering emulsion system for pharmaceutical molecule vitamin E nicotinate

The use of Pickering emulsions for biocatalysis is gaining increased attention. However, the extensive application is greatly limited due to the enzyme inactivation. Herein, a biocatalytic Pickering emulsion with high-performance utilizing cellulose nanocrystals immobilized lipases (CNCs-Lps) particles as stabilizer is advanced and applied for the synthesis of Vitamin E nicotinate. CNCs-Lps display high activity and reusability due to the construction of biocatalytic microreactor in the O/W emulsion system. The yield of vitamin E nicotinate ester reached up to 83 %. More importantly, the CNCs-Lps can be reused due to the similar principles to microreactors in Pickering emulsions. Reusability test showed that the CNCs-Lps could be recovered from the emulsion system by centrifugation and the yield of vitamin E nicotinate retains 78 % of initial value after five cycles, demonstrating overwhelming advantage than the fair counterpart with free lipases.

A cellulose nanocrystal-based dual response of photonic colors and fluorescence for sensitive benzene gas detection

Benzene, as a common volatile organic compound, represents serious risk to human health and environment even at low level concentration. There is an urgent concern on visualized, sensitive and real time detection of benzene gases. Herein, by doping Fe3+ and graphene quantum dots (GQDs), a cellulose nanocrystal (CNC) chiral nematic film was designed with dual response of photonic colors and fluorescence to benzene gas. The chiral nematic CNC/Fe/GQDs film could respond to benzene gas changes by reversible motion. Moreover, chiral nematic film also displays reversible responsive to humidity changes. The resulting CNC/Fe/GQDs chiral nematic film showed excellent response performance at benzene gas concentrations of 0–250 mg/m3. The maximal reflection wavelength film red shifted from 576 to 625 nm. Furthermore, structural color of CNC/Fe/GQDs chiral nematic film change at 44 %, 54 %, 76 %, 87 %, and 99 % relative humidity. Interestingly, due to the stability of GQDs to water molecules, CNC/Fe/GQDs chiral nematic film exhibit fluorescence response to benzene gas even in high humidity (RH = 99 %) environment. Besides, we further developed a smartphone-based response network system for quantitively determinization and signal transformation. This work provides a promising routine to realize a new benzene gas response regime and promotes the development of real-time benzene gas detection.

Eco-friendly cellulose-based antioxidation film by partial esterification

Cellulose nanocrystals (CNCs) have received increasing attention because of their superior dispersion and thermal stability. In this study, TEMPO-oxidized cellulose nanocrystal (TOCNC) multifunctional antioxidationantioxidation films (TOCNC–GA film) were prepared by the esterification of TOCNC and gallic acid (GA). TOCNC–GAX films, where X represents the ratio of the amount of GA to the amount of TOCNC, were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The films with the GA:TOCNC ratio of 1:1 achieved higher interfacial compatibility than the other films. The mechanical properties and water resistance of the TOCNC–GA films were superior than those of pure TOCNC films. Moreover, the original TOCNC structure changed owing to the presence of GA, which endowed a certain thermoplasticity owing to the formation of ester groups. The antioxidation properties of the TOCNC–GA1 films reached 43.8 % and 71.85 % after 6 and 24 h, respectively, as evaluated by the 2,2-biphenyl-1-picrylhydrazyl method and the free radical scavenging activities of the TOCNC–GA1 films. The innovative development of the functional antioxidation film presented in this paper has great potential for use in antioxidation packaging materials and food preservation.

Preparation of waterborne anti-counterfeiting ink based on dual luminescent nanohybrids of bacterial cellulose nanocrystals and lanthanide‑nitrogen co-modified GQDs

To address the growing challenge of counterfeit prevention, this study developed a novel anti-counterfeiting ink system based on bacterial cellulose nanocrystals (BCNC) and lanthanide (Er, Yb)‑nitrogen (N) co-dropped graphene quantum dots (GQDs), which exhibited both photoluminescence (PL) and upconversion photoluminescence (UCPL) fluorescent properties as well as excellent rheological characteristics. The Er/Yb/N-GQDs with positive charges were synthesized by a one-step hydrothermal method and subsequently assembled with negatively charged BCNC through electrostatic self-assembly to fabricate a novel nanohybrid, Er/Yb/N-GQDs-BCNC. Raman spectroscopy results indicated an enhancement in the graphitization of GQDs due to lanthanide modification. The TEM results demonstrated a homogeneous distribution of Er/Yb/N-GQDs on BCNC, while XRD, FTIR, and XPS analyses confirmed their physical binding, thus validating the successful synthesis of novel nanohybrids. Then, Er/Yb/N-GQDs-BCNC was introduced into PVA waterborne ink and exhibited dual anti-counterfeiting properties by emitting blue fluorescence at Em 440 nm under Ex 370 nm and green fluorescence at Em 550 nm under Ex 980 nm. Furthermore, the incorporation of BCNC significantly enhanced the thixotropic behavior and yield stress of the PVA waterborne ink. This enhancement made the dual anti-counterfeiting fluorescent ink more suitable for diversified applications on different devices and various substrates, thus providing a novel approach for convenient and rapid information encryption and high security anti-counterfeiting.

Controlled reaction dynamics of cellulose: Revealing the dual morphology nanocrystals

Cellulose nanocrystals exhibit diverse morphology with embedded crystallinity derived from the ordered crystalline regimes of cellulose fibers. Acid hydrolysis parameters controls the morphology of nanocrystals and is the primary efficient route for the synthesis of cellulose nanocrystals. In this study, we explored the impact of temperature on the morphology engineering of cellulose nanocrystals derived from banana pseudostem by oxalic acid hydrolysis, an underexplored method. Confirmation of successful cellulose extraction was achieved through fibrous morphology observed in FESEM and TEM analyses. X-ray diffraction and Raman spectroscopy affirmed the presence of type II cellulose. Notably, for the first time, we report the derivation of toroidal and spherulitic sheet-like morphologies in cellulose nanocrystals synthesized by hydrothermal method from banana psuedostem. Our investigation revealed that cellulose hydrolysis at 120 °C yields nanocrystals characterized by toroidal and spherulitic sheet-like morphologies with excellent crystallinity, as confirmed by FESEM and TEM analyses, with average thicknesses of 13.70 nm and 18.05 nm, respectively. Interestingly, elevating the hydrolysis temperature to 180 °C led to the collapse of these structures into carbon dots, exhibiting notable cyan emission.

Preparation of CO2‐based waterborne polyurethane/cellulose nanocrystal composite films and research of their radiative cooling properties

AbstractConventional colored radiative cooling (ColPRC) has a single color and limited reflection of visible light bands, which affects its radiative cooling effect, and the introduction of multiple photonic crystal structures can improve its radiative cooling performance. Therefore, in this study, a composite film was established by cross‐linking cellulose nanocrystals (CNC) with CO2‐based waterborne polyurethane (WPU) to obtain multistage structural colors. X‐ray diffraction pattern, thermogravimetric analysis, scanning electron microscopy, spectral analysis, and so on were used to examine the structure and properties of the films. The results showed that with the increase of CNC content, the color shifted blue, the crystallinity increased, the flame retardancy increased, but the thermal stability decreased; the addition of WPU assists in resisting moisture; the reflectivity of the multistage structured films is improved in the VIS–NIR range compared with the monochromatic films (an average increase of 5%), which helps to reduce solar irradiation in the visible wavelengths; high emissivity (≈90%) in the atmospheric window, which facilitates deep‐space heat exchange. The maximum temperature difference of the multistage structural color film can reach 6°C under strong solar irradiation. This research can be applied in photovoltaic devices or outdoor thermal management to provide new ways to address human energy efficiency.

Acrylic acid incorporated nanocellulose/acrylamide ion-conductive hydrogels for wearable sensors

In this paper, CNC/PAM/PAA interpenetrating network composite hydrogels were prepared from acrylamide (AM), cellulose nanocrystals (CNC), and acrylic acid (AA) by in situ free radical polymerization. CNC/PAM/PAA-Ca2+ hydrogels were successfully prepared by adding CaCl2 to the mixed solution to introduce ions. The composite hydrogels were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy and tested for their mechanical, electrical, and sensing properties. The experimental results showed that the copolymerization reaction of AM and AA resulted in hydrogels with excellent mechanical properties, with a maximum tensile strength of 98.7 kPa and an elongation at break of 643.6%. In addition, the introduction of Ca2+ ions significantly improved the conductivity and sensitivity of the hydrogel. The developed multifunctional poly (AM-AA) hydrogels were able to stably detect the relative changes in electrical resistance during cyclic tensile, compressive, and bending motions of a human finger, which is expected to be widely used in flexible sensor devices.

Cellulose nanocrystal‐modified bio‐based aqueous polyurethane coating agent for kraft paper packaging

AbstractWith the implementation of the “plastic restriction order” and the demand for sustainable society development, biodegradable coatings derived from biomass materials have garnered significant interest. This study presents the synthesis of a double‐salt bio‐based waterborne polyurethane (PLA‐WPU) by utilizing poly(lactic acid) polyol (PLA) and isophorone diisocyanate (IPDI) as the main raw materials, along with 2,2‐dihydroxymethylpropionic acid (DMPA) and sodium ethylenediamine ethanesulfonate (A‐95) as a hydrophilic chain extender. Synergistic reinforcement of PLA‐WPU using hydrophobically modified cellulose nanocrystals (M‐CNC) and polycarbonate diimide (PDCDA). At an M‐CNC content of 3% relative to the effective mass of PLA‐WPU, the tensile strength reached 36.12 MPa. After 8 days a lipase PBS solution, the degradation rate reached 54%. Excellent waterproof performance was observed, exhibiting a contact angle of 143.5°. When applied as a surface coating on kraft paper, the Cobb 60 value decreased from 74.0 to 28.6 g/m2, while increasing the tensile strength by 451.3%. Importantly, the kraft paper maintained excellent waterproofing, mechanical strength, and high barrier properties even after repeated folding, high and low‐temperature conditions, and exposure to varying pH solutions. It proved to be both degradable and recyclable, making it a promising alternative to liner paper or plastic membrane, especially in food packaging.

Valorization of Eichhornia crassipes for the production of cellulose nanocrystals further investigation of plethoric biobased resource

Chemical processing is among the significant keys to tackle agro-residues utilization field, aiming to obtain value-added materials. Extraction of cellulose nanocrystals (CNCs) is an emerging route to valorize lignocellulosic wastes into high value particles. In this investigation, effect of acidic hydrolysis duration was monitored on size and morphology of obtained crystals; namely: CNCs from Nile roses fibers (NRFs) (Eichhornia crassipes). Different acidic hydrolysis duration range or different characterization techniques set this article apart from relevant literature, including our group research articles. The grinded NRFs were firstly subjected to alkaline and bleaching pretreatments, then acid hydrolysis process was carried out with varied durations ranging from 5 to 30 min. Microcrystalline cellulose (MCC) was used as reference for comparison with NRFs based samples. The extracted CNCs samples were investigated using various techniques such as scanning electron microscopy (SEM), Atomic force microscopy (AFM), Raman spectroscopy, and thermogravimetric (TGA) analysis. The figures gotten from SEM and AFM depicted that NRFs based CNCs appeared as fibril-like shapes, with reduced average size when the NRFs underwent pulping and bleaching processes. This was indicated that the elimination of hemicellulose and lignin components got achieved successfully. This outcome was proven by chemical composition measurements and TGA/DTG curves. On the other hand, AFM-3D images indicated that CNCs topology and surface roughness were mostly affected by increasing hydrolysis durations, besides smooth and homogeneous surfaces were noticed. Moreover, Raman spectra demonstrated that the particle size and crystallinity degree of NRFs based CNCs can be affected by acidic hydrolysis durations and optimum extraction time was found to be 10 min. Thermal stability of extracted CNCs-NRFs and CNCs-MCC was measured by TGA/DTG and the kinetic models were suggested to identify the kinetic parameters of the thermal decomposition of CNCs for each acid hydrolysis duration. Increasing hydrolysis duration promoted thermal stability, particularly for NRFs based CNCs. Results showcased in this article add new perspective to Nile rose nanocellulose and pave down the way to fabricate NRFs based humidity nano-sensors.

Synthesis and properties of transparent PMMA/cellulose nanocomposites prepared by in situ polymerization in green solvent

AbstractIn order to contribute to the demanded sustainability transparent poly(methyl methacrylate) (PMMA) composites with cellulose nanocrystals (CNC) up to high shares of 50 wt% were prepared by in situ radical polymerization in green solvent Cyrene. The weight average molecular weights of PMMA were in the range from 144,000 to 160,000 g mol−1 and the dispersity was in the range of 1.49 to 1.89 with high conversion of monomer to polymer. The DSC thermal analysis showed that the glass transition temperature of pure PMMA was at 99°C while in composites increased from 103°C up to 129°C with the increase of CNC from 1 wt% to 50 wt%. TGA shows that the addition of CNC does not have a significant effect on the thermal stability of PMMA. In composites Young's modulus increases with the increasing CNC ratio and composites with 50 wt% of CNC showed more than twice the modulus of the PMMA matrix. The SEM images indicate uniform distribution of CNC in polymer matrix. The transparent and semitransparent PMMA/cellulose composites of improved sustainability with higher modulus of elasticity and glass transition temperature can be used as lightweight materials for a wide range of technical and everyday applications as well as optical lenses or acoustic lenses for ultrasound transducers and other devices.Highlights Cellulose nanocrystals/PMMA composites fabricated by a green in situ process. Synthesized PMMA matrices have high molecular weights. Improved elastic modulus and glass transition temperature were achieved. Prioritizing eco‐friendly chemicals for a greener production approach.

Cellulose nanocrystals mediated spontaneous weaving of ZIF-67 hybrid networks: Enhanced peroxymonosulfate activation and rapid removal of dye

Inter-connected zeolite imidazolate framework-67 (ZIF-67) hybrid networks were successfully synthesized by a cellulose nanocrystals (CNCs) mediated spontaneous weaving strategy, which was denoted as ZIF-67@CNC, and was applied to activate peroxymonosulfate (PMS) for Rhodamine B (RhB) degradation. Characterizations results demonstrated that the ZIF-67 nanocrystals are encapsulated within CNCs and subsequently arranged in a string-like configuration. In comparison to pristine ZIF-67, the ZIF-67@CNC catalyst presented superior performances for RhB dye removal both in terms of degradation efficiency and rate, as the kinetic rate constant increased 5.8-fold. This finding was attributed to the improvement in oxygen-containing groups and meso/microporous structures after the introduction of CNCs, leading to efficient binding to compounds and rapid molecular diffusion. Moreover, the ZIF-67@CNC exhibited remarkable stability throughout the catalysis process in aqueous solutions owing to the robust crosslinking between negatively charged CNCs and positively charged cobalt ions, which significantly mitigated the potential secondary pollution of cobalt to the environment. This research opens up new possibilities for the design of highly efficient and durable ZIF-67-based catalysts to promote future wastewater treatment technology.