Preparation and characterization on cellulose nanofiber film

In this study, cellulose nanofibers were obtained from wood pulp using a chemo-mechanical method and thin films were made of these cellulose nanofibers. The morphology of the films was studied by scanning electron microscopy (SEM). SEM image analysis revealed that the films were composed of cellulose nanofibers with an average diameter of around 32 nm. Other properties were also characterized, including the degree of crystallinity by X-ray diffraction, chemical bonding by infrared attenuated total reflectance analysis, and thermal properties by differential scanning calorimetry. The foldable, strong, and optically translucent cellulose nanofiber films thus obtained have many potential applications as micro/nano electronic devices, biosensors and filtration media, etc.

Blend films of natural wool and cellulose prepared from an ionic liquid

Natural wool/cellulose blends were prepared in an ionic liquid green solvent, 1-butyl-3-methylimidazolium chloride (BMIMCl) and the films were formed subsequently from the coagulated solutions. The wool/cellulose blend films show significant improvement in thermal stability compared to the coagulated wool and cellulose. Moreover, the blend films exhibited an increasing trend of tensile strength with increase in cellulose content in the blends which could be used for the development of wool-based materials with improved mechanical properties, and the elongations of the blends were considerably improved with respect to the coagulated films of wool and cellulose. It was found that there was hydrogen bonding interaction between hydroxyl groups of wool and cellulose in the coagulated wool/cellulose blends as determined by Fourier transform infrared (FTIR) spectroscopy. The ionic liquid was completely recycled with high yield and purity after the blend film was prepared. This work presents a green processing route for development of novel renewable blended materials from natural resource with improved properties.

Cellulose and hemicellulose digestion by herbivorous terrestrial crustaceans

Cellulose, the main component of plant cell walls, is insoluble and difficult to digest enzymatically. This research discovered that herbivorous land crabs have an efficient gastric mill in the stomach which disrupts this insoluble material, and a range of highly specialised enzymes that can then break down the cellulose.

Effect of cellulose nanofiber dimensions on sheet forming through filtration

Four different cellulose nanofibers samples were prepared from northern bleached softwood kraft fibers. Fiber diameter distributions were measured from SEM images. Fiber aspect ratios ranging from 84 to 146 were estimated from fiber suspension sedimentation measurements. Three samples had heterogeneous distributions of fiber diameters, while one sample was more homogeneous. Sheet forming experiments using filters with pores ranging from 150 to 5 μm showed that the samples with a heterogeneous distribution of fiber dimensions could be easily formed into sheets at 0. 2% initial solids concentration with all filter openings. On the other hand, sheets could only be formed from the homogenous sample by using 0. 5% or more initial solids content and a lower applied vacuum and smaller filter openings. The forming data and estimated aspect ratios show reasonable agreement with the predictions of the crowding number and percolation theories for the connectivity and rigidity thresholds for fiber suspensions.

Fabrication of carbon nanofiber by pyrolysis of freeze-dried cellulose nanofiber

The possibility of fabricating carbon nanofibers from cellulose nanofibers was investigated. Cellulose nanofiber of ~50 nm in diameter was produced using ball milling in an eco-friendly manner. The effect of the drying techniques of cellulose nanofibers on the morphology of carbon residue was studied. After pyrolysis of freeze-dried cellulose nanofibers below 600 °C, amorphous carbon fibers of ~20 nm in diameter were obtained. The pyrolysis of oven-dried precursors resulted in the loss of original fibrous structures. The different results arising from the two drying techniques are attributed to the difference in the spatial distance between cellulose nanofiber precursors.

Visible light activated TiO2/microcrystalline cellulose nanocatalyst to destroy organic contaminants in water

Hybrid TiO2/microcrystalline cellulose (MC) nanophotocatalyst was prepared in situ by a facile and simple synthesis utilizing benign precursors such as MC and TiCl4. The as-prepared nanocomposite was characterized by XRD, XPS, BET surface area analyzer, UV–vis DRS and TGA. Surface morphology was assessed by the means of SEM and HR-TEM. Statistics-based factorial design (FD) was adopted to investigate the effect of precursors concentrations and therefore to optimize the nanocomposite synthesis through catalytic adsorption of methylene blue (MB) from aqueous solutions. The results indicated that TiO₂/MC nanocomposites were photocatalytically active in diminishing 40–90% of MB in 4 h.

A study of pyrolysis conditions on carbon nanofiber properties produced from freeze-dried cellulose nanofibers

In the present work, carbon nanofibers were prepared by pyrolysis of freeze-dried cellulose nanofiber and the effect of pyrolysis conditions on the properties of carbon nanofiber was studied. SEM analysis revealed that slow heating rates below 400oC are critical to maintain the fibrous morphology after carbonization. The present study demonstrated the possibility of producing carbon nanofibers of ≤ 30 nm in diameter by a simple and scalable method.