Cellulose Nanowhiskers Research Articles

Tannin-encapsulated electrospun nanofibrous membrane of cellulose nanowhiskers-reinforced polysulfone for colorimetric detection of iron(III)

A nanocomposite of tannic acid and cellulose nanowhiskers (CNW)-reinforced polysulfone (PSF) was used to develop a metallochromic nanofibrous membrane sensor for iron(III) in aqueous media. Tannic acid was used as an active detecting probe, whereas the CNW@PSF composite was employed as a hosting material. Cellulose nanowhiskers (7–12 nm) were obtained from microcrystalline cellulose (MCC). According to the coloration parameters, a bathochromic shift from colorless (415 nm) to purple (561 nm) occurs when ferric cations bind to the phenolic hydroxyls of the tannic acid probe. The concentration of ferric was found to be directly correlated to the extent of the color change, demonstrating a detection limit of 0.1–250 ppm. This could be attributed to the creation of a coordinative complex between ferric ions and phenolic tannic acid. The generated nanofibers were inspected by energy-dispersive X-ray (EDX) and scanning electron microscopy (SEM). The electrospun nanofibrous membrane showed an average diameter between 75 and 150 nm. The tannic acid-containing nanofibers are remarkably reusable and simple. The tannic acid-encapsulated polysulfone nanofibrous membrane was used to detect various metal ions, demonstrating a high selectivity for Fe3+. The ideal pH range for the identification of Fe3+ was determined to be in the range of 4.25–6.75.

Study of the electrospun PVDF fibrous membrane in capturing particulate matters in smoke by the synergy between GO and CNWs

The filtration capability can be effectively adjusted by involving the incorporation of fillers into filter materials. Here, we present a promising filter material for capturing particulate matters in smoke, a polyvinylidene fluoride (PVDF) fibrous membrane modified by cellulose nanowhisker (CNWs) and graphene oxide (GO), which was prepared by a facile electrospinning method. GO with oxygen-containing groups can improve the capability of capturing particle owing to its excellent adsorption performance. CNWs with highly ordered crystalline regions can alter the dimension and properties of PVDF fibers. The synergistic effect of GO and CNWs enabled uniform fiber diameter, higher porosity, and better filtration property as compared with that of pristine PVDF membranes. Experimental results demonstrated a significant improvement in the filtration efficiency of PVDF fibrous membranes after blending with GO and CNWs. The filtration data showed that the filtration efficiency (95.58%) of GO/CNWs/PVDF membrane was higher than that (87.68%) of CNWs/PVDF membrane and that (86.36%) of PVDF membrane. The reusability for capturing pollutants showed that the fibrous membrane could keep a certain filtration capability (93.85%) after 5 cycles. Computational results suggested there was an interaction between GO and smoke pollutants (monoterpene) and the addition of GO play an effect on the filtration efficiency of fibrous membranes. These results showed that GO/CNWs/PVDF fibrous membranes was ideal filter materials for air pollutant.

A one-dimensional bacterial cellulose nano-whiskers-based binary-drug delivery system for the cancer treatment

It's currently a challenge to design a drug delivery system for chemotherapy with high drug contents and minimal side effects. Herein, we constructed a novel one-dimensional binary-drug delivery system for cancer treatment. In this drug delivery system, drugs (doxorubicin (DOX) and resveratrol (RES)) self-assemble on bacterial cellulose nano-whiskers (BCW) and are subsequently encapsulated by polydopamine (PDA) with high encapsulation efficiencies (DOX: 81.53 %, RES: 70.32 %) and high drug loading efficiencies (DOX: 51.54 %, RES: 36.93 %). The cumulative release efficiencies can reach 89.27 % for DOX and 80.05 % for RES in acidic medium within 96 h. The BCW/(DOX + RES)/PDA can enter tumor cells easily through endocytosis and presents significant anti-cancer effects. Furthermore, the released-RES plays a protective role in normal cells through up-regulation of antioxidant enzymes activities and scavenging of reactive oxygen species. Taken together, the one-dimensional BCW/(DOX + RES)/PDA binary-drug delivery system can be used for the anticancer treatment along with slight side effects.

From Chitin Nanowhisker Colloidal Dispersions to Anisotropic Microfibers: Structural Evolution in Its Transformation Process as Revealed by Synchrotron Wide-Angle X-ray Diffraction Measurements.

Nanowhiskers in a colloidal dispersion are known to form chiral nematic liquid crystals (CNLC), as seen in a cellulose nanowhisker or so-called cellulose nanocrystal and chitin nanowhisker. In our related work, we clarified that once the thus-created chitin nanowhiskers with surface modified by chitosan (CTWK-CS) in CNLC phase were wet-spun, we could directly obtain anisotropic microfibers containing the highly ordered CTWK-CS. This drastic structural transformation from CNLC to anisotropic microfibers might relate to several important stages, i.e., stage (i) is the alignment of CTWK-CS initiated by a specific concentration and flow to create aggregation in the CNLC state, stage (ii) is the coagulation of CTWK-CS in CNLC to transform to microfibers, and stage (iii) is the drying of the thus-extruded microfibers to allow CTWK-CS alignment. The present work sets up the experimental systems simulating stages (i) and (iii) to reveal the orientational behavior of CTWK-CS and the structural evolution, respectively, by synchrotron 2D WAXD measurement. In stage (i), the high degree of the parallel alignments of CTWK-CS with the chain axis oriented along the flow direction of the colloidal dispersions confirms that the flow and concentration synergistically controlled CTWK-CS alignment. In contrast, for stage (iii), the poor c-axial orientation of CTWK-CS in as-spun wet microfibers gradually changed to the high degree of c-axial orientation along the fiber direction during drying process, indicating a reorientation of CTWK-CS along with dehydration. The present study declares an in situ observation of the direct wet spinning of nanowhiskers about their remarkable alignments in the sheared colloidal dispersions (stage (i)) and their random-to-high reorientation during the drying process of the as-spun wet microfiber (stage (iii)).

The Development of Polylactide Nanocomposites: A Review

Polylactide materials present a promising alternative to petroleum-based polymers due to their sustainability and biodegradability, although they have certain limitations in physical and mechanical properties for specific applications. The incorporation of nanoparticles, such as layered silicate (clay), carbon nanotubes, metal or metal oxide, cellulose nanowhiskers, can address these limitations by enhancing the thermal, mechanicals, barriers, and some other properties of polylactide. However, the distinct characteristics of these nanoparticles can affect the compatibility and processing of polylactide blends. In the polylactide nanocomposites, well-dispersed nanoparticles within the polylactide matrix result in excellent mechanical and thermal properties of the materials. Surface modification is required to improve compatibility and the crystallization process in the blended materials. This article reviews the development of polylactide nanocomposites and their applications. It discusses the general aspect of polylactides and nanomaterials as nanofillers, followed by the discussion of the processing and characterization of polylactide nanocomposites, including their applications. The final section summarizes and discusses the future challenges of polylactide nanocomposites concerning the future material’s requirements and economic considerations. As eco-friendly materials, polylactide nanocomposites offer significant potential to replace petroleum-based polymers.

Biopolymers and their Nanocomposites: Current Status and Future Prospects

Abstract: For many years, petroleum-based polymers have been successfully enhanced by the addition of nanoparticles as additives. Carbon nanotubes, graphene, nanoclays, 2-D layered materials, and cellulose nano whiskers are a few of the several nanoreinforcements that are currently being researched. In comparison to unmodified polymer resin, the use of these nanofillers with bio-based polymers could improve a wide range of physical properties, including barrier, flame resistance, thermal stability, solvent uptake, and rate of biodegradability. This nano-reinforcement is a very appealing method to create new functional biomaterials for a variety of applications because these enhancements are typically achieved at minimal filler content.

Synthesis of Biodegradable Plastic Film from Chitosan-Glycerol with Cellulose Nanowhiskers of Coconut Coir as Reinforcing Agent

Abstract This research was conducted to synthesize biodegradable plastic films from chitosan and glycerol with the addition of cellulose nanowhiskers as a reinforcing agent. Cellulose synthesis of nanowhiskers from coconut husks was carried out with 3 phases, i.e., pre-treatment, bleaching, and sulphuric acid hydrolysis with a concentration of 55%. The result of cellulose hydrolysis in the form of needle-like nanowhiskers with an average of 223.6 nm particle size and a crystallinity index of 34.27% were shown through the results of FTIR, SEM, PSA, and XRD. Plastic film was made by blending method, which was mixing whole material then stirred until homogeneous and printed at room temperature. This study showed that the addition of cellulose nanowhiskers 3% can increase the tensile strength value up to 50 MpA, water resistance by 88.86%, and the biodegradation rate by 0.51 mg/day, but the value decreased if the addition of cellulose nanowhiskers was more than 3%. This was influenced by the rigid properties of cellulose nanowhiskers and experienced aggregation if it was added in excess. In conclusion, the addition of cellulose nanowhiskers with precise concentration can increase the tensile strength, water resistance, and the rate of biodegradation in the plastic film from chitosan-glycerol.

Development of cellulose nanowhisker–gallic acid antioxidant bioconjugate via covalent conjugation and supramolecular interactions: A comparative study

A new supramolecular antioxidant bioconjugate based on cellulose nanowhisker (CNW) and gallic acid (GA) was developed by grafting β-CD on the surface of CNW and then employing host- guest chemistry to involve GA. Our challenge was to explore the effect of supramolecular conjugation of antioxidant molecules versus their covalent binding on the CNW backbone on the antioxidant activity. The synthesis of these products was confirmed using Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC) analyses. The antioxidant activity of gallic acid (GA) containing products, both products including its non-covalent interactions with CNW-g-β-CD and covalent bonding with CNW were experimentally evaluated using DPPH test. Theoretical calculations using Gaussian software and the density functional theory (DFT) method were also performed. The results showed that GA's antioxidant activity increased in non-covalent conjugated form. Hydrogen atom transfer (HAT) was used to predict the antioxidant activity of GA in computational methods. These findings not only expand our understanding of the structure-activity relationships in antioxidant systems but also provide valuable insights that can aid in the design and development of novel biopolymer-based antioxidants with improved properties.

Nanohybrids with potential barrier property and antimicrobial activity for application in sustainable polymer food packaging: A mini‐review

AbstractPackaging has important functions for products, contributing to their protection and presenting information. Recognizing that food loss and waste affect all countries, it is necessary to search for alternatives that change this scenario, such as active packaging. Particles with sizes between 1 and 100 nanometers (nanoparticles) are incorporated into polymeric materials because they are capable of improving or even providing properties that the film formed by the pure polymer does not have, due to its surface area being greater than that of macro‐sized particles. If two nanoparticles are previously combined to form a nanohybrid before being dispersed in a polymeric matrix, in addition to having this purpose, they can provide even better results when incorporated, due to the synergistic effects that can be attributed to the nanoparticles used. The utilization of active packaging composed of nano‐hybrids within biodegradable polymers holds significant potential for reducing solid plastic waste and the generation of persistent microplastics, thereby positively impacting human health. In this literature review, the effects of nanohybrid on antibacterial and barrier properties for application in food packaging in polymeric matrices were investigated using materials such as: nickel nanoparticles, zinc oxide nanoparticles, silver nanoparticles, copper oxide nanoparticles, cellulose nanowhiskers, Cloisite 30B, sodium alginate, poly(ethylene oxide), starch, poly(vinyl alcohol), chitosan and gelatin. The results were found to show the efficiency of nanohybrids in polymeric matrices, decreasing the water vapor and oxygen permeability and also increasing the antibacterial activity, which can prevent illnesses stemming from contaminated food occurs.

Tailoring natural rubber composites via surface-modified nanocellulose whiskers with sodium isopropyl xanthate: characterization and performance analysis

Tailoring natural rubber composites via surface-modified nanocellulose whiskers with sodium isopropyl xanthate: characterization and performance analysis

Cellulose nanowhiskers‐reinforced polymer nanofibers for photoresponsive authentication

AbstractThe objective of the current study is to develop novel photochromic polyurethane (PUR) nanofibrous films supported with cellulose nanowhiskers (CNW) and immobilized with nanoparticles of alkaline‐earth doped aluminate (NAEA) using the highly efficient and low‐cost solution blowing spinning (SBS) technique. CNW revealed a crystal diameter of 4–8 nm, and a crystal length of 55–105 nm. The solution blown spun nanofibers exhibited diameters of 250–450 nm. In order to prepare a transparent film, CNW and NAEA must be dispersed efficiently in the PUR composite. When supported with CNW, the efficiency of PUR nanofibrous films was strengthened. Cellulose paper sheets were coated with the colorless NAEA/CNW@PUR films to emit a green light at 518 nm upon excitation at 365 nm as proved by photoluminescence spectra. The prepared nanofibrous films exhibited efficient optical photochromic characteristics for potential security encoding applications. The nanofibers‐coated papers showed high photochromic reversibility without fatigue. The current approach can be reported as an efficient technology for authentication of commercial products.

Preparation of novel polyurethane/activated carbon/cellulose nano-whisker nanocomposite film as an efficient adsorbent for the removal of methylene blue and basic violet 16 dyes from wastewater

The purpose of this research was to evaluate the effectiveness of a porous and flexible polyurethane (PU)-based nanocomposite consists activated carbon (AC) and cellulose nano-whisker (CNW) on adsorption of methylene blue (MB) and basic violet16 (BV16) as two industrial dyes. The morphology, hydrophilicity, chemical structure, and mechanical properties of the fabricated nanocomposite films were investigated using FE-SEM, water contact angle, ATR-FTIR and tensile tests respectively. The water contact angle tests exhibited that the addition of 1.0 wt% CNW resulted in the highest hydrophilicity in the nanocomposite film. The results of the adsorption tests showed that the nanocomposites containing 1.0 wt% AC have the best performance in the adsorption of dyes. In addition, the effect of parameters such as contact time, pH, adsorbent dosage, and temperature on the removal efficiency of dyes was investigated. It was found that the adsorption mechanism of MB and BV16 dyes by the PU nanocomposite can occur as a combination of chemical and physical adsorption. Kinetic and isotherm studies of the adsorption also showed that the adsorption of MB and BV16 dyes on the PU/AC/CNW nanocomposite follows the pseudo-second-order kinetic model and the Freundlich isotherm. The maximum adsorption capacity (qm) of 71.4 mgg-1 for BV16 dye and 67.1 mgg-1 for MB dye showed that the PU/AC/CNW nanocomposite can be used as an efficient adsorbent for adsorption of BV16 and MB dyes.

Grafting bacterial cellulose nanowhiskers into whey protein/essential oil film composites: Effect on structure, essential oil release and antibacterial properties of films

The development of bio-based primary packaging is imperative to improve food safety and quality, along with mitigating the environmental pollution resulting from the increasing production of packaging wastes. Whey protein concentrate (WPC) has received significant attention as an alternative raw material for edible films production, whereas an area of many ongoing researches has been the inclusion of bio-based compounds to formulate functional edible films. This study elaborated the development of WPC edible films fortified with different essential oils (EO) to assess antimicrobial activity against gram-positive (Staphylococcus aureus and Listeria monocytogenes) and gram-negative (Salmonella enteritidis and Pseudomonas aeruginosa) food-borne pathogens. Subsequently, the effect of grafting bacterial cellulose nanowhiskers (BCNW) in film composites was evaluated for WPC/oregano EO (WPC/OEO) films, which showed the highest antibacterial activity. Notably, increasing the concentration of grafted BCNW entailed a proportional increase on the inhibitory activity. In specific, antibacterial activity increased up to 80% when 10% BCNW was grafted in WPC/OEO films. Inclusion of BCNW and homogenous distribution of OEO into the film blend was pointed out through Raman analysis. In addition, AFM and SEM analysis revealed that inclusion of BCNW and OEO into the film matrix led to the formation of rough films with pores. This structural change enhanced the release capacity of OEO, that was further confirmed through a release kinetic experiment. This study indicated that BCNW addition positively affected whey protein films properties, thereby envisaging the potential development of sustainable food packaging materials with tailor-made properties.

Three‐phase bio‐nanocomposite natural‐rubber‐based microfibers reinforced with cellulose nanowhiskers and 45S5 bioglass obtained by solution blow spinning

AbstractAiming at biomedical applications, the present work developed a new bio‐nanocomposite fibrous mat based on natural rubber (NR) reinforced with 45S5 bioglass particles (BG) and cellulose nanowhiskers (CNW), which reveals excellent mechanical properties, good biocompatibility and bioactivity properties. Analyses of the specimens were conducted by means of morphological observations (SEM) and thermal analysis (TG/DTG), as well as mechanical tests used to verify the effect of the incorporation of BG particles and CNW on the ultimate properties of these flexible NR‐CWN/BG fibrous membranes. An SEM analysis revealed that all filaments possessed a ribbon‐like morphology, with increasing diameters as the BG concentration increased. This likely results from an increased viscosity of the solution used for fiber blowing. In comparison with neat NR fibrous mats, the ultimate mechanical properties of bio‐nanocomposites were significantly improved due to the presence of CNW and BG particles dispersed in the NR matrix. According to the TG/DTG analysis, the specimens' thermal stability was unaffected by the high BG content, and the thermal profiles were similar, with isoprene chains decomposition of the NR occurring between 350 and 450°C. In‐vitro analysis on fibroblasts confirmed that the bio‐nanocomposite fibrous mats are noncytotoxic. It was found that fibrous mats enhanced cellular growth and hold great promise for tissue engineering applications.

Improved performance of poly(lactic acid) nanocomposites with poly(butyl acrylate)‐modified cellulose nanowhiskers

AbstractPoly(butyl acrylate) (PBA) was grafted onto cellulose nanowhiskers (CNW) via transesterification in an ionic liquid and solution polymerization in water. Fourier‐transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, x‐ray photoelectron spectroscopy, and x‐ray diffraction were used to determine the structure and morphology of the PBA‐modified CNW (CNW‐g‐PBA). Poly(lactic acid) (PLA)/CNW‐g‐PBA nanocomposites were prepared by solution casting. The inclusion of CNW‐g‐PBA significantly increased the composite strength, toughness, and thermal stability. The maximum tensile strength and elongation‐at‐break values were approximately 28% and 268%, respectively, higher than those of PLA. The fracture surface showed typical ductile fracture characteristics. The glass‐transition temperature raised from 56.7 for PLA to 60.3°C for CNW‐g‐PBA (5 wt% PBA), and the crystallinity rose from 1.6% to 10.3%. These findings show that the modification of nanowhiskers increased their compatibility with, and dispersion in, PLA. These results show that a combination of surface‐functionalized CNWs and PLA provides biocomposites with a broad range of applications, for example, in packaging and biomedical products.Highlights CNW‐g‐PBA was prepared by transesterification and solution polymerization route. PLA/CNW‐g‐PBA exhibited strong and tough performance. Compatibility mechanism have been developed.

Preparation of new eco-friendly covalent dynamic network based on polylysine, cellulose nanowhisker dialdehyde, and chitosan for curcumin delivery

Preparation of new eco-friendly covalent dynamic network based on polylysine, cellulose nanowhisker dialdehyde, and chitosan for curcumin delivery

Large scalable, ultrathin and self-cleaning cellulose aerogel film for daytime radiative cooling

Passive cooling strategy shows great potential in mitigating global warming and reducing energy consumption. Because of the high emissivity in the atmospheric transparency window (λ ≈ 8–13 µm), cellulose is considered as a good candidate for radiative cooling. However, traditional cellulose coolers generally show poor solar reflection and can be polluted by dust outside, thereby resulting in poor daytime cooling efficiency. To address these drawbacks, we developed sustainable cellulose nanowhiskers (CNWs)/ZnO composite aerogel films with favorable optical performance, mechanical robustness, and self-cleaning function for efficient daytime radiative cooling, which can be achieved via freeze casting and hot-pressing process. Due to formation of multi-level porous structure and chemical bonds (Si-O-C/Si-O-Si), such aerogel film exhibited high solar reflectance (97%) and high infrared emittance (92.5%). It achieved a sub-ambient temperature drop of 6.9 °C under direct sunlight in hot weather. Most importantly, the surface roughness and low surface energy enable cellulose aerogel film hydrophobicity (contact angle = 133°), thereby resulting in an anti-dust function. This work provides insight into the design of sustainable thermal regulating materials to realize carbon neutrality.

Green Biodegradable Polylactide-Based Polyurethane Triblock Copolymers Reinforced with Cellulose Nanowhiskers

A novel series of biodegradable polylactide-based triblock polyurethane (TBPU) copolymers covering a wide range of molecular weights and compositions were synthesized for potential use in biomedical applications. This new class of copolymers showed tailored mechanical properties, improved degradation rates, and enhanced cell attachment potential compared to polylactide homopolymer. Triblock copolymers, (TB) PL-PEG-PL, of different compositions were first synthesized from lactide and polyethylene glycol (PEG) via ring-opening polymerization in the presence of tin octoate as the catalyst. After which, polycaprolactone diol (PCL-diol) reacted with TB copolymers using 1,4-butane diisocyanate (BDI) as a nontoxic chain extender to form the final TBPUs. The final composition, molecular weight, thermal properties, hydrophilicity, and biodegradation rates of the obtained TB copolymers, and the corresponding TBPUs were characterized using 1H-NMR, GPC, FTIR, DSC, and SEM, and contact angle measurements. Results obtained from the lower molecular weight series of TBPUs demonstrated potential use in drug delivery and imaging contrast agents due to their high hydrophilicity and degradation rates. On the other hand, the higher molecular weight series of TBPUs exhibited improved hydrophilicity and degradation rates compared to PL-homopolymer. Moreover, they displayed improved tailored mechanical properties suitable for utilization as bone cement, or in regeneration medicinal applications of cartilage, trabecular, and cancellous bone implants. Furthermore, the polymer nanocomposites obtained by reinforcing the TBPU3 matrix with 7% (w/w) bacterial cellulose nanowhiskers (BCNW) displayed a ~16% increase in tensile strength, and 330% in % elongation compared with PL-homo polymer.

Fabrication and characterization of additively manufactured CNT-bioglass composite scaffolds coated with cellulose nanowhiskers for bone tissue engineering

During the fabrication of scaffolds for bone regeneration, it is difficult to concurrently achieve bioactivity, mechanical performance, and ease of fabrication. Additionally, implant surface functionalization is a topic of intense research to improve bone-to-implant interaction and augment bone repair. Accordingly, this study reports additively manufactured (AM) 45S5 Bioglass scaffolds reinforced with functionalized multi-walled carbon nanotubes (CNTs) that were dip-coated with cellulose nanowhiskers (CNWs). Carboxymethyl cellulose (CMC) was used as an ink carrier that showed suitable shear thinning behavior. The fabricated scaffolds were characterized using x-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), and energy dispersive x-ray spectroscopy (EDS). 45S5 Bioglass reinforcement with CNTs and coating with CNWs led to an increase in the compressive strength from 20.5 to 27 MPa (∼32% enhancement), while the toughness increased from 2.08 to 3.92 MJ/m3 (∼88% enhancement). Additionally, structural analysis based on microcomputed tomography images showed that the AM-fabricated scaffolds exhibited suitable porosity, pore size, pore throat size, and interconnectivity. Moreover, the coating of the scaffold with CNWs increased the surface roughness, which may aid in bone cell attachment on the scaffold surface. Finally, these scaffolds were found to be bioactive, as revealed by in vitro studies in simulated body fluid (SBF). These results show the potential for efficient fabrication of hybrid scaffolds with controlled structure, bioactivity, and required toughness as well as strength for bone tissue engineering.

Composites of resorcinol and hexamethylenetetramine modified nanocellulose whiskers as potential biofiller in natural rubber latex: synthesis, characterization and property evaluation

Composites of resorcinol and hexamethylenetetramine modified nanocellulose whiskers as potential biofiller in natural rubber latex: synthesis, characterization and property evaluation