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Nanofibrillated cellulose (NFC) has found extensive potential and existing utilizations across various industries. Nonetheless, a notable constraint of NFC lies in its inherent hydrophilic nature, which restricts its suitability for non-aqueous application. This study aims at synthesising hydrophobic NFC through a two-step surface modification by reacting NFC with tannic acid and amine group. The study also investigated the effect of using various alkylamines on the properties of modified NFC. The hydrophobic NFC was characterized using various analytical techniques namely Thermogravimetric Analysis (TGA), X-Ray Diffraction analysis (XRD), Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectroscopy (FTIR), elemental analysis, and contact angle measurements. The present study also looked into the possible use of modified NFC as a pharmaceutical excipient for the delivery of water insoluble curcumin. The analysis of curcumin binding onto the modified NFC was conducted using UV–Visible spectrophotometry. The findings from the study indicated that the modified NFC effectively bound a substantial quantity of curcumin (80 % - 87 %) and the binding varied for samples of different degree of substitution. [ABSTRACT FROM AUTHOR]

In this study, hydrophobic nanochitin aerogels are synthesized via one-pot synthesis strategy and subsequent freeze-drying technique, employing nanochitin, hexanal and formaldehyde as primary components. The tert-butyl alcohol (TBA)/water binary solvents are found efficient for well mixing of hydrophilic nanochitin and hydrophobic hexanal, which is fundamental for fabricating hydrophobic aerogels with water contact angle as high as 105°. Schiff base reaction between amino groups in nanochitin and aldehyde groups in hexanal is believed to be the main reason for the successful hydrophobization of nanochitin aerogels. Additionally, formaldehyde is employed to enhance the mechanical properties of aerogels via ice templated crosslinking technique. Nanochitin aerogels prepared in this work possess surface area as high as 237 m2 g−1, which are believed benefiting from the TBA/water binary solvents with lower density, smaller ice crystal and convenience in freeze-drying. The ultralow density, ultrahigh porosity, and hydrophobicity nature also lead to the advanced oil adsorption (as high as 210 g g−1) of nanochitin aerogels. The simple preparation process, nature sustainability and excellent adsorption performance is believed rendering nanochitin aerogels as a viable alternative for the remediation of oil spills. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights • The acetoacetyl group is used to modify cotton via the heterogeneous reaction. • Cotton-acac-Gen-ODA shows durable hydrophobic and antibacterial performance. • The heterogeneous strategy is a versatile way to design new functional materials. Abstract Herein, the acetoacetyl group was directly anchored on the surface of cotton fabric (Cotton-acac) via heterogeneous transesterification. This surface modification strategy was systematically characterized by Fourier transform infrared spectroscopy, solid-state 13C nuclear magnetic resonance spectroscopy, X-ray diffraction, and thermogravimetric analysis, which confirmed it was a mild and efficient process. Besides, Cotton-acac was used as the versatile intermediate post-modified with gentamicin (Gen) and octadecyl amine (ODA) molecules to impart cotton fabric dual functions with hydrophobic and antibacterial properties. The resulting cotton fabric showed dual and outstanding hydrophobic and antibacterial performance against E. coli and S. aureus , with the bactericidal rates of over 99.99% and the water contact angle of 145°even after 10 cycles of standard washing. Therefore, the heterogeneous modification provided a benign and versatile method for regulating the interfacial properties of the cellulosic materials, with the possibility of post modification for various applications through the acetoacetyl chemistry. [ABSTRACT FROM AUTHOR]

Cellulose films have attracted extensive interest in the field of burgeoning electronic devices. However, it remains a challenge to simultaneously address the difficulties including facile methodology, hydrophobicity, optical transparency, and mechanical robustness. Herein, we reported a coating-annealing approach to fabricate highly transparent, hydrophobic, and durable anisotropic cellulose films, where poly(methyl methacrylate)- b -poly(trifluoroethyl methacrylate) (PMMA- b -PTFEMA) as low surface energy chemicals was coated onto regenerated cellulose films via physical (hydrogen bonds) and chemical (transesterification) interactions. The resultant films with nano-protrusions and low surface roughness exhibited high optical transparency (92.3 %, 550 nm) and good hydrophobicity. Moreover, the tensile strength of the hydrophobic films was 198.7 MPa and 124 MPa in dry and wet states, respectively, which also showed excellent stability and durability under various conditions, such as hot water, chemicals, liquid foods, tape peeling, finger pressing, sandpaper abrasion, ultrasonic treatment, and water jet. This work provided a promising large-scale production strategy for the preparation of transparent and hydrophobic cellulose-based films for electronic device protection as well as other emerging flexible electronics. [ABSTRACT FROM AUTHOR]

In order to improve the superhydrophobic and oil-wet properties of raw cotton fibers come from Jiangsu province, China. A novel adsorbent, hydrophobic cotton fibers (HCF) with an excellent superhydrophobic and larger length was synthesized via modified sol–gel method and examined for the removal of nitrobenzene in aqueous solution. Results show that the treated raw cotton fibers exhibited outstanding non-wettability with the WCA of 152° and the larger length of 0.2–0.4 cm, which offers an opportunity to separation in for the removal of nitrobenzene. It was found that adsorption isotherm and kinetics of nitrobenzene onto HCF were well described by the Freundlich and pseudo-second-order kinetic models, respectively. The thermodynamic data showed that the nitrobenzene adsorption onto HCF was a spontaneous, endothermic and physisorption reaction. The monolayer adsorption capacity of nitrobenzene was found to be 16.85 mg/g at 30 °C. [ABSTRACT FROM AUTHOR]

Oily wastewater is generated in diverse industrial processes, and its treatment has become crucial due to increasing environmental concerns. Herein, silanized cellulose was prepared by sol–gel reaction between microcrystalline cellulose (MCC) and hexadecyltrimethoxysilane (HDTMS) using for oil–water separation. The silanized cellulose was characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). A higher mass ratio of HDTMS to MCC made silanized cellulose become looser, and showed lower water absorbency. The silanized cellulose exhibited specific separation performance towards vegetable oil–water mixture (not for mineral oil–water mixture) with separation efficiency of 99.93%. Moreover, the separation was fast with a water flux of 4628.5 L m −2 h −1 . The separation efficiency still remained at 99.77% even after recycling for 10 times. [ABSTRACT FROM AUTHOR]

Graft copolymerisation of methyl methacrylate (MMA) onto Agave angustifolia was conducted with ceric ammonium nitrate (CAN) as the redox initiator. The maximum grafting efficiency was observed at CAN and MMA concentrations of 0.91 × 10 −3 and 5.63 × 10 −2 M, respectively, at 45 °C for 3 h reaction time. Four characteristic peaks at 2995, 1738, 1440, and 845 cm −1 , attributed to PMMA, were found in the IR spectrum of grafted cellulose. The crystallinity index dropped from 0.74 to 0.46, while the thermal stability improved upon grafting. The water contact angle increased with grafting yield, indicating increased hydrophobicity of cellulose. SEM images showed the grafted cellulose to be enlarged and rougher. The changes in the physical nature of PMMA-grafted cellulose can be attributed to the PMMA grafting in the amorphous regions of cellulose, causing it to expand at the expense of the crystalline component. [ABSTRACT FROM AUTHOR]

To obtain the nanofibriled cellulose from natural pine needles, a combination of chemical pretreatments and subsequently ultrasonic treatments was employed for removing the hemicelluloses and lignins and splitting the bundled cellulose into pine needle nanofibers. Using SEM and diameter distribution method, it was confirmed that the obtained pine needle nanofibers had a narrow diameter from 30 to 70 nm. The crystalline type of the pine needle nanofibers was the cellulose I type. The crystallinity reached 66.19%, which was increased by 7.61% as compared with the raw material pine needles. The TGA and DTG results showed that the degradation temperature of the nanofibers was increased to approximately 267 and 352 °C compared with 221 and 343 °C of the raw material fibers, respectively. Furthermore, the highly flexible and ultralight pine needle nanofibers aerogels were prepared from the aqueous pine needle nanofibers solution using the freezing-drying technique. Aerogels were studied by SEM observation and nitrogen gas adsorption. The mechanical properties were measured in compression for aerogels. This study provides a new opportunity to fabricate novel nanomaterials from waste biomass materials, which is crucial for the fully utilizing of abundant biomass resources. [ABSTRACT FROM AUTHOR]

Herein, a facile strategy was proposed for preparing a high-strength and super-hydrophobic packaging paper with improved moisture and air barrier properties, which was derived from cellulosic pulps, micro-fibrillated cellulose (MFC), and nano-silica (n-SiO 2). Owning to the laminated process followed by spraying approach, MFC and n-SiO 2 were assembled onto two surfaces of the cellulose paper base, respectively, endowing the mechanical behaviors and superhydrophobic performance of this biodegradable composite papers as packaging material. The as-obtained multilayered papers demonstrated impressive dry tensile strength and remarkable wet tensile strength of 6542.5 N/m and 5875 N/m, which were increased by 56% and 2277%, respectively. In addition, the multilayered paper with rational mechanical properties possessed low permeabilities of air (3.17 × 10−3 μm·Pa−1·s−1), oxygen (9.687 cm3·m−2·day−1·atm), and water vapor (378.24 g·m−2·day−1), respectively, as well as a superhydrophobic performance with the contact angle of ~151.2°. Overall, the feasibility of large-scale production of biodegradable packaging materials in the paper-making industry is demonstrated by the fact that the micro/nanostructures and hydrophobic surfaces could be directly constructed on cellulosic paperboard. Synopsis In this work, the feasibility of large-scale production of biodegradable packaging materials in the paper-making industry is demonstrated by the fact that the micro/nanostructures and hydrophobic surfaces could be directly constructed on cellulosic paperboard. [Display omitted] [ABSTRACT FROM AUTHOR]

An environmental-friendly lipase induced highly hydrophobic NFC film was fabricated through lipase induced dimethyl adipate (DA) esterification followed by silver nanowires (AgNWs) coating for strain sensor application. Due to the lipase activation, the substitution degree (DS NMR) of 0.18 was achieved, which was three times higher than that of the control sample (without lipase treatment of NFC-DA). As a result, the water contact angle (WCA) of lipase induced adipated-NFC film was reached to 105 ± 3° from 50 ± 2.3° of NFC-DA. In addition, the cellulose structure and performance were well maintained after lipase induced esterification, confirmed by AFM, SEM, TG/DTG, and XRD analysis. After AgNWs coating and annealing, the hydrophobic NFC film-based strain sensor exhibited excellent sensitivity towards human motion, such as finger/wrist movement in real-time, even under wet conditions. Overall, a highly hydrophobic NFC film-based strain sensor was fabricated, which has promising application in wearable devices for human motion monitoring. Schematic representation of lipase induced highly hydrophobic NFC film. [Display omitted] • Hydrophobic NFC film-based strain sensor was fabricated though lipase induced esterification and silver nanowires coating. • Dimethyl adipate was efficiently grafted onto cellulose by lipase inducing esterification reaction. • Silver nanowires was uniformly coated on the NFC film using a rolling bar. • The fabricated strain sensor could monitor human motion in both dry and wet condition. [ABSTRACT FROM AUTHOR]

Abstract: In this report, ZnO nanoparticles embedded cellulose acetate (CA) fibrous membrane with multifunctional properties have been prepared through electrospinning method. The morphology of the electrospun composite membrane was analyzed by scanning electron microscope (SEM). It was found that the polymer concentration in the solution has a significant effect on the morphology of the fibers. The optical property of the sample was tested using photo luminescence (PL) spectra. There is no significant change in the emission features of cellulose acetate with the addition of ZnO. The anti-bacterial property of the sample was studied using disk diffusion method. The wettability of the pure and composite fibrous membrane was also studied by measuring the contact angle of water on the membrane. It was observed that the embedded ZnO in the CA was responsible for the hydrophobic nature of the surface. [Copyright &y& Elsevier]

Abstract: In this report, ZnO nanoparticles embedded cellulose acetate (CA) fibrous membrane with multifunctional properties have been prepared through electrospinning method. The morphology of the electrospun composite membrane was analyzed by Scanning Electron Microscope (SEM). It was found that the polymer concentration in the solution has a significant effect on the morphology of the fibers. The optical property of the sample was tested using Photo Luminescence (PL) spectra. There is no significant change in the emission features of cellulose acetate with the addition of ZnO. The anti-bacterial property of the sample was studied using disc diffusion method. The wettability of the pure and composite fibrous membrane was also studied by measuring the contact angle of water on the membrane. It was observed that the embedded ZnO in the CA was responsible for the hydrophobic nature of the surface. [Copyright &y& Elsevier]

Abstract: Bacterial cellulose preserving the microfibrillar morphology was partially acetylated by the solvent-free acetylation method using acetic anhydride in the presence of iodine as a catalyst. The results showed that within the range of catalyst amounts studied, the overall degree of substitution increased as the amount of iodine used increased. We also found that the reaction time and temperature had an active influence on the extent of acetylation. X-ray diffraction profiles indicated that acetylation proceeded from the surface to the interior of BC nanofibers, and scanning electron microscopy images revealed that even low levels of acetylation were effective to make the nanofibers separated from each other. NMR analysis indicated the regio-nonselective reactivity of the OH groups in the glucose units in the acetylation process. The obtained acetylated BC membrane shows more hydrophobic surface and good mechanical properties which is in favor of enhancing the hydrophobic non-polar polymeric matrix. [Copyright &y& Elsevier]

Hydrophobized chitosan derivatives, hexyl chitosan (HCS), dodecyl chitosan (DCS), and phthaloyl chitosan (PhCS) of approximately 30 and 50% degree of substitution (%DS) reacted with glycidyltrimethylammonium chloride (GTMAC) to incorporate hydrophilic positively charged groups of N -[(2-hydroxyl-3-trimethylammonium)propyl] and yielded amphiphilic quaternized chitosan derivatives. They can assemble into spherical nanoparticles with a hydrodynamic diameter of ~100–300 nm and positive ζ-potential values (+15 to +56). Their anti-biofilm efficacy was evaluated against the dental caries pathogen, Streptococcus mutans. Among all derivatives, the one having 30%DS of hexyl group and prepared by reacting with 1 mol equivalent of GTMAC (H 30 CS-GTMAC) showed the best performance in terms of its aqueous solubility, the lowest minimum inhibitory concentration (138 μg/mL) and the minimum bactericidal concentration (275 μg/mL) which are superior to the unmodified chitosan. Its equivalent anti-biofilm efficacy to that of chlorhexidine suggests that it can be a greener antibacterial agent for oral care formulations. [Display omitted] • Amphiphilic chitosan derivatives with varied composition were synthesized. • All derivatives were water soluble at a neutral pH. • The derivatives with hexyl groups are the most effective antibacterial agent. • The anti-biofilm efficacy against S. mutans is concentration dependent. • The anti-biofilm property was comparable to chlorhexidine. [ABSTRACT FROM AUTHOR]

Abstract: The influence of molecular structure of small ionised molecules on the thermo-reversible sol:gel phase transition of a hydroxyalkyl cellulose ether has been investigated with respect to an l-amino acid series. The concentration dependency of the phase transition temperature of 1% w/w hydroxypropyl methylcellulose solutions in the presence of different amino acids was studied turbidimetrically. The effects of different amino acids ranged from −33.54 to +45.52°CM−1. Correlations between the effect on phase transition temperature and amino acid molecular properties showed the strongest relationships with amino acid hydrophobicity. Small hydrophilic amino acids lowered the transition temperature, whereas large hydrophobic aromatic amino acids increased this temperature. The effect of different amino acids was proposed to be a balance between the ability of their hydrophilic regions to dehydrate and disrupt the polymer hydration sheath, and the ability of their hydrophobic regions to associate with and solubilise the methoxyl-dominated regions of the polymer. [Copyright &y& Elsevier]

Plastic pollution has inspired the preparation of environmentally friendly bio-based plastics that can replace petroleum-based plastics. Herein, a composite film with oxygen and water resistant properties was prepared by a fluidized bed method, employing bio-based cellulose acetate (CA) as raw material, glycerol as a plasticizer, and chitosan and silica as additives. The addition of 15% chitosan greatly reduced the oxygen transmission rate of the CA film by 83.5%, and increased the tensile stress and tensile strain of the composite membrane, reaching 26.5 MPa and 22.2%, respectively. The deposition of silica particles is able to compensate for the undesired increase in the hydrophilicity caused by the addition of chitosan, and tune the hydrophilic nature of the surface of the CA/CS films to the hydrophobic nature, which is desirable for water-resistant applications. The prepared composite film displays good oxygen and water resistant properties and can be used for food packaging and related applications. • A bio-based degradable composite film for the substitution of plastics was prepared. • The oxygen transmission rate of cellulose acetate film was reduced by 83.5% with the addition of 15% chitosan. • The hydrophobicity of the composite film was enhanced by depositing silica particles. • The composite film has good mechanical property and good thermal stability. [ABSTRACT FROM AUTHOR]

• The preparation of aerogels was based on refined fibers. • The magnetic hydrophobic aerogel was made by using MTES and Fe 3 O 4 nanoparticles. • The aerogel had high adsorption capacity(181 g/g) and good reusability. A novel approach was introduced to prepare very low density, highly porous, economic, reusable, hydrophobic, and magnetic cellulose aerogels from hardwood dissolving pulp via a simple freeze-drying procedure. The aerogels showed outstanding adsorption efficiency for several oils and organic solvents and demonstrated excellent selectivity for absorbing oil from an oil/water mixture. Moreover, they were easily collected by an external magnet, indicating excellent recyclability and reusable for at least 10 cycles while still retaining supreme adsorption capacity (up to 181 g/g for silicone oil). This study proposes an economic and novel method for the large-scale preparation of hydrophobic and magnetic cellulose aerogels, making them a promising candidate for the efficient and sustainable cleaning of oils and chemical spills. [ABSTRACT FROM AUTHOR]

• Sucrose-based ionic liquid (IL) is successfully used to prepare hydrophobic TPS. • TPS with the maximum tensile strength of 8.4 MPa and water contact angle of 117° is obtained. • Intenser interactions between Cl atoms of the IL and HO- groups of starch are detected. • Chloride atoms of the IL play crucial roles in the thermoplasticization of TPS. • The prepared TPS is promising to replace many unsustainable petroleum-based polymers. It is still a big challenge to obtain hydrophobic thermoplastic starch with outstanding mechanical performance due to the inevitable usage of typical hydrophilic plasticizers like glycerol during processing. Herein, we report a novel hydrophobic thermoplastic starch using a supramolecularly induced thermoplasticization technique. To achieve this aim, a functional sucrose-based ionic liquid crystal (ILC) including numerous chloride atoms has been firstly synthesized, and the obtained ILC molecules are then used as supramolecular inducers to thermoplasticize corn starch granules. Thermoplasticity and hydrophobicity of the prepared supramolecularly induced thermoplastic starch (STPS) with different ILC contents have been extensively investigated. Mechanism of the supramolecularly induced thermoplasticization has been investigated using molecular simulation as well. The prepared STPS with the maximum tensile strength of 8.4 MPa and water contact angle of about 117° show large potential applications in green and sustainable packaging materials. [ABSTRACT FROM AUTHOR]

• Development of slender nano-ribbons from spherical xyloglucan nanoparticles by degalactosylation. • The transition results from stronger hydrophobic interaction. • Reduced number of hydrophilic galactose caused decreased water solubility. As a common side-chain residue of polysaccharide, galactose plays a significant role in multiple aspects of the macromolecules. This study showed how degalactosylation induced drastic self-assembly transition of xyloglucan from spherical aggregates toward ribbon-like aggregates, and how it led to largely decreased water solubility and apparent viscosity within a short range of galactose removal ratio. To better understand this phenomenon, the size of the ellipsoid-like aggregated nanoparticles were carefully measured and compared, and it was found out that those nanoparticles which lost more galactose residues turned out to be more slender and tend to bind and stack closely in parallel, thereby forming huge ribbon-like aggregates. The galactose residue is considered as the hydrophilic group, and the decreased number of which caused a more hydrophobic behavior. [ABSTRACT FROM AUTHOR]

Hydrophobic and thermally-stable cellulose nanocrystals (CNCs) were synthesized by polycarpolactone diol (PCL diol) grafting via click chemistry strategy. The synthesis was designed as a three-step procedure containing azide-modification of CNCs, alkyne-modification of PCL diol and sequent copper(I)-catalyzed azide-alkyne cycloaddition reaction. The structure of azide-modified CNCs and alkyne-modified PCL diol, the structure, hydrophobic ability and thermal stability of click products CNC-PCL were characterized. FTIR, XPS and H 1 NMR results indicated a successful grafting of the N 3 groups onto the CNCs, synthesis of PCL diol-CCH, and formation of the CNC-PCL material. CNC-PCL had enhanced dispersion in the non-polar solvent chloroform owing to the well-maintained microscale size and PCL-induced hydrophobic surface. The thermal stability of CNC-PCL was largely increased due to the grafting of thermally-stable PCL. This work demonstrates that click chemistry is an attractive modification strategy to graft CNCs with polyester chains for further potential application in polymer composites., (Copyright © 2018 Elsevier Ltd. All rights reserved.)