Water-resistant Cellulose Research Articles

Ion Selective and Water Resistant Cellulose Nanofiber/MXene Membrane Enabled Cycling Zn Anode at High Currents

AbstractAqueous rechargeable zinc ion batteries (ZIBs) are regarded as a promising candidates for next‐generation energy storage devices but strongly hindered by the limited utilization of the zinc metal anode (below 5%) due to the active water/anion corrosion. Herein, an ion selective and water‐resistant cellulose nanofiber (CNF)/MXene composite membrane has been developed through molecular sieving to restrict active water and anions from the electrode/electrolyte interface through dehydration of zinc ions, avoiding the water/anion‐induced corrosion/decomposition. In this way, the CNF/MXene@Zn anode exhibits significantly enhanced coulombic efficiency (99.5 % at 10 mA cm‐2) and low voltage hysteresis. Moreover, coated with CNF/MXene composite membrane, zinc symmetric batteries can be operated at the extremely high current of 100 mA cm‐2 and ultra‐high Zn utilization of 88.2% to achieve record‐high cumulative plating capacity of 12 Ah cm‐2. Furthermore, the full vanadium dioxide (VO2) |CNF/MXene@Zn batteries exhibit a high capacity of 357 mAh g‐1 at 2 A g‐1 and retain 93.3% of the capacity after 500 cycles. Moreover, at negative/ positive capacity (N/P) ratio of 2.8, the CNF/MXene membrane coated zinc is able to stably cycle for 100 cycles, demonstrating the potential for high energy zinc battery. This designed CNF/MXene membrane enables ZIBs as viable energy storage devices for practical applications.

Highly foldable, robust and water-resistant cellulose specialty paper reinforced by aramid nanofibers

Highly foldable, robust and water-resistant cellulose specialty paper reinforced by aramid nanofibers

Water Resistant Cellulose Acetate Based Photopolymer for Recording of Volume Phase Holograms

The development of environmentally robust photosensitive materials for holographic recording is crucial for applications such as outdoor LED light redirection, holographic displays and holographic sensors. Despite the progress in holographic recording materials development, their sensitivity to humidity remains a challenge and protection from the environment is required. One approach to solving this challenge is to select substrate such as cellulose acetate, which is water resistant. This work reports the development of a cellulose-based photopolymer with sensitivity of 3.5 cm2/mJ and refractive index modulation of 2.5 × 10−3 achieved in the transmission mode of recording. The suitability for holographic recording was demonstrated by recording gratings with the spatial frequency of 800 linepairs/mm. The intensity dependence of the diffraction efficiency of gratings recorded in 70 μm thick layers was studied and it was observed that the optimum recording intensity was 10 mW/cm2. The robustness of the structures was studied after immersing the layer in water for one hour. It was observed that the diffraction efficiency and the surface characteristics measured before and after exposure to water remain unchanged. Finally, the surface hardness was characterized and was shown to be comparable to that of glass and significantly higher than the one of PVA-based acrylamide photopolymer.

A Review of Water-Resistant Cellulose-Based Materials in Pharmaceutical and Biomedical Application.

Cellulose, having huge reserves of natural polymers, has been widely applied in pharmaceutical and biomedicine fields due to its good biocompatibility, biodegradability, non-toxicity and excellent mechanical properties. At present, water- resistant metal-based and petroleum-based materials applied in the medical field have obvious problems of poor biocompatibility and high cost. Therefore, water-resistant cellulose- based materials with good biocompatibility and low price have become an attractive alternative. This review aims to summarize the preparation of water-resistant cellulose- based materials and their potential application in pharmaceutical and biomedical in recent years. Common hydrophobic treatments of cellulose fibers or paper were overviewed. The preparation, properties and applications of water-resistant cellulose- based materials in the pharmaceutical and biomedical fields were summarized. Common hydrophobic treatments of cellulose fibers or paper were divided into chemical modification (graft polymerization, crosslinking, solution casting or dip-coating), physico-chemical surface modifications (plasma treatments, surface patterning, electrostatic spraying and electrowetting) and physical processing (electrostatic spinning, SAS process and 3D EHD printing). These hydrophobically processed cellulose fibers or paper could be prepared into various water-resistant cellulose-based materials and applied in pharmaceutical excipients, drug-loaded amphiphilic micelles, drug-loaded composite fibers, hydrophobic biocomposite film/coatings and paper-based detectors. They presented excellent water resistance and biocompatibility, low cytotoxicity and high drug loading ability, and stable drug release rate, etc., which could be used for water-insoluble drugs carriers, wound dressings, and medical testing equipment. Currently, water-resistant cellulose-based materials were mainly applied in water-insoluble drugs delivery carriers, wound dressing and medical diagnosis and presented great application prospects. However, the contradiction between hydrophobicity and mechanical properties of these reported water-resistant cellulose-based materials limited their wider application in biomedicine such as tissue engineering. In the future, attention will be focused on the higher hydrophobicity of water-resistant cellulose-based materials with excellent mechanical properties. In addition, clinical medical research of water-resistant cellulose-based materials should be strengthened.

Water and humidity-induced shape memory cellulose nanopaper with quick response, excellent wet strength and folding resistance

Abstract Water-induced shape memory polymers (SMPs) are the desired candidates for the uses in the fields of surgical operation, smart textile, and aerospace. However, most of water-induced SMPs are non-biodegradable petroleum-based polymers, and a quick response to water of SMPs is usually accompanied with the loss of wet strength due to the over hydration. To address this issue, in this work, a water resistant cellulose nanopaper (CNP) was firstly prepared with the cellulose nanofibrils (CNFs) produced by formic acid hydrolysis, and then the obtained CNP was modified via immersing in chitosan (CS) for the preparation of a robust CNP with quick water and humidity responses. Results showed that the original shape of the modified CNP after folding could immediately respond to water (

Enhanced antibacterial profile of nanoparticle impregnated cellulose foam filter paper for drinking water filtration

Filtration is a promising water treatment method to purify drinking water. To develop highly efficient drinking water filter paper, water-resistant cellulose foam paper with a high wet strength property was fabricated using diverse metal oxide (e.g., copper oxide (CuO), zinc oxide (ZnO), and silver oxide (Ag2O)) nanoparticles. These nanoparticles were synthesized using the hydrothermal reaction method. Their morphological structures were studied using a field emission scanning electron microscope (FESEM). The presence of coated nanoparticles on the cellulose foam filter was verified by energy dispersive X-ray spectroscopy (EDX) methods. The antibacterial performance of different types of modified cellulose foam filters was studied against E. coli, P. aeruginosa, B. subtilis, and B. cereus strains using the zone of inhibition test. The antibacterial profile of the cellulose foam filter impregnated with Ag2O nanoparticles, when tested against different types of bacteria, exhibited higher antibacterial activity than the cellulose foam filter impregnated with ZnO and CuO nanoparticles.

Water-resistant cellulosic filter containing non-leaching antimicrobial starch for water purification and disinfection

Water-resistant cellulose foam paper was developed in this work in an attempt to improve the antimicrobial activity of cellulose foam paper for capture and deactivation of pathogenic microorganisms existed in water. Results indicated that the cellulose foam paper could significantly improve household water quality by incorporating guanidine-based polymer modified with starch or called antibacterial thermoplastic starch (ATPS) into fibre network in the presence of proper amount of fiber fines. Ring diffusion testing demonstrated that no ATPS diffused around or underneath of samples, verifying that cellulose foam filter added by ATPS were of non-leaching type. Furthermore, the viability of bacteria before and after filtering and the structure of cellulose foam paper were analyzed via fluorescence microscopy and scanning electron microscopy images. The findings further proved the effectiveness of antimicrobial cellulose foam in deactivating pathogens, E.coli in particular.

Development and preliminary field validation of water-resistant cellulose nanofiber based coatings with high surface adhesion and elasticity for reducing cherry rain-cracking

This study was aimed to systematically develop and validate cellulose nanofiber (CNF)-based hydrophobic coatings (Innofresh™) for reducing cherry rain-cracking through a lab-scale optimization study and the preliminary field validation trials. The base coating formulation consist of 0.5% CNF (w/w) and 0.5% potassium sorbate (KSb) (w/w). For optimizing the coating formulations with desired water resistance, wettability and elasticity, three different types of plasticizer (glycerol, PEG 400, and sorbitol) and their concentrations (0, 0.05, and 0.1% (w/w)), as well as surfactant mixture (1:1 ratio of Tween 80 and Span 80) at 0.05, 0.1, and 0.2% (w/w) were evaluated as additional functional substances in the base coating formulation. It was found that 0.5% CNF/0.5% KSb based coatings containing 0.1% glycerol and 0.1% or 0.2% surfactant mixture provided high wettability and elasticity along with superior water resistance. The effectiveness of the optimized coating formulations on reducing cherry rain-cracking was validated through two field studies conducted in Chile and the United States during November–December, 2014 and May–June, 2015, respectively. The 0.5% CNF/0.5% KSb/0.1% glycerol coating containing 0.1% or 0.2% surfactant mixture resulted in significant reduction in cherry rain-cracking (∼31.18–44.60%) (P<0.05), while no any detrimental effect on fruit firmness, size, soluble sugar, pedicel/fruit retention force, and color was observed in comparison with non-coated cherries. Therefore, the simple, but versatile CNF-based coatings incorporated with an appropriate amount of glycerol and surfactant was effective to reduce cherry rain-cracking without impacting fruit growth and quality.

Hierarchical structure in microbial cellulose: what happens during the drying process.

We present a time-resolved investigation of the natural drying process of microbial cellulose (MC) by means of simultaneous small-angle neutron scattering (SANS), intermediate-angle neutron scattering (IANS) and weighing techniques. SANS was used to elucidate the microscopic structure of the MC sample. The coherent scattering length density of the water penetrating amorphous domains varied with time during the drying process to give a tunable scattering contrast to the water-resistant cellulose crystallites, thus the contrast variation was automatically performed by simply drying. IANS and weighing techniques were used to follow the macroscopic structural changes of the sample, i.e., the composition variation and the loss of the water. Thus, both the structure and composition changes during the whole drying process were resolved. In particular, the quantitative crosscheck of composition variation by IANS and weighing provides a full description of the drying process. Our results show that: i) The natural drying process could be divided into three time regions: a 3-dimensional shrinkage in region I, a 1-dimensional shrinkage along the thickness of the sample in region II, and completion in region III; ii) the further crystallization and aggregation of the cellulose fibrils are observed in both the rapid drying and natural drying methods, and the rapid drying even induces obvious structural changes in the length scale of 7-125 nm; iii) the amount of "bound water", which is an extremely thin layer of water surrounding the surfaces of cellulose fibrils, was estimated to be ∼ 0.35 wt% by the weighing measurement and was verified by the quantitative analysis of SANS results.

Structure and Properties of Cellulose Films Coated with Polyurethane/Benzyl Starch Semi-IPN Coating

A series of water-resistant cellulose films was prepared by coating castor oil based polyurethane (PU)/benzyl starch (BS) semi-interpenetrating polymer networks (semi-IPN). All of the coated films, with a very thin coating layer of about 0.4 μm, exhibited much better optical transmittance, water resistance, and mechanical properties than the original regenerated cellulose (RC) film, suggesting a strong interface interaction between PU/BS coating and cellulose substrate. The BS concentration in the coating had a significant effect on the properties of the coated films. With an increase of BS concentration in the coating from 10 to 70 wt %, the tensile strength and storage modulus of the coated films increased. Especially, as the tensile strength achieved a maximum value of 102 MPa, the elongation at break of the coated film still maintained a relatively higher value of 10%. Meanwhile, the coated films displayed good biodegradability, and the biodegradation rate increased with increasing BS concentration in...

Structure, properties and biodegradability of water resistant regenerated cellulose films coated with polyurethane/benzyl konjac glucomannan semi-IPN coating

We prepared a series of novel water-resistant cellulose films by coating castor oil-based polyurethane (PU)/benzyl konjac glucomannan (B-KGM) semi-interpenetrating polymer networks (semi-IPN) on regenerated cellulose (RC) films, which was obtained from cotton linter in 6 wt% NaOH/5 wt% thiourea aqueous solution by coagulating with 5 wt% H 2SO 4 aqueous solution. The effect of B-KGM content on interfacial structure, thermal stability, mechanical properties in dry and wet states and biodegradability of the coated films were investigated by Fourier transform infrared spectra, ultraviolet spectroscopy, transmission electron microscopy, dynamic mechanical thermal analysis, tensile test and biodegradation test. The results indicate that PU prepolymer molecules in the semi-IPN coating penetrate simultaneously into the RC film, and give rise to a shared PU network between B-KGM and cellulose. B-KGM in the semi-IPN coating layer plays an important role in enhancement of the mechanical properties, water resistivity, thermal stability, light transmittance of the coated films. The tensile strength of the coated films increases from 86.3 to 114.9 MPa in dry state and from 33.8 to 56.4 MPa in wet state, as well as the light transmittance at 800 nm from 79% to 90% when B-KGM content increases from 0 wt% to 80 wt%. The biodegradation rates of the coated films increase with an increase of B-KGM content and the their biodegradation half-time is less than 80 days.

Interfacial Structure and Properties of Regenerated Cellulose Films Coated with Superthin Polyurethane/Benzoyl Konjac Glucomannan Coating

Novel water-resistant cellulose films from castor-oil-based polyurethane (PU) and benzoyl konjac glucomannan (BKGM) semi-interpenetrating polymer networks (semi-IPNs) forming a superthin coating on the cellulose films, which was regenerated from cellulose in 6 wt % NaOH/5 wt % thiourea aqueous solution, were prepared. The tensile strength (σb), water resistivity (R), light transmittance (Tr), and size constriction (Sc) of the coated films with coatings of 0.2−0.6 μm thickness and with different BKGM contents in the coatings were investigated. The values of σb, R, and Sc were 93 MPa, 0.57, and 0.8%, respectively, when the BKGM content in the coating was 5 wt %. Even when the coating layer thickness was 0.2 μm, the coated films still had higher tensile strength (80 MPa) and water resistivity (0.47) than cellulose film. The results from Fourier transform infrared spectroscopy, ultraviolet spectroscopy, transmission electron microscopy, and electron probe microanalysis indicate that much of the improvement of...