Cellulose

http://link.springer.com/journal/10570

List of Papers (Total 172)

Iα to Iβ mechano-conversion and amorphization in native cellulose simulated by crystal bending

The bending of rod-like native cellulose crystals with degree of polymerization 40 and 160 using molecular dynamics simulations resulted in a deformation-induced local amorphization at the kinking point and allomorphic interconversion between cellulose Iα and Iβ in the unbent segments. The transformation mechanism involves a longitudinal chain slippage of the hydrogen-bonded...

Insights into degradation pathways of oxidized anhydroglucose units in cellulose by β-alkoxy-elimination: a combined theoretical and experimental approach

Depolymerization of cellulose starting from an oxidized anhydroglucose unit through β-alkoxy-elimination, triggered by alkaline media, is one of the key reactions responsible for cellulose aging. This study investigates the detailed mechanisms for the chain cleavage by a combination of experimental and quantum chemical methods. Three model compounds for oxidized anhydroglucose...

Salt sorption on regenerated cellulosic fibers: electrokinetic measurements

Streaming potential measurements were conducted on lyocell and viscose fibers, to determine the relative order in sorption extents of salt cations and anions. The sorption of K+ was greater than Na+ ions, and the sorption extents of the anions, Cl− and Br−, were similar. Previously, we had examined accessibility of the same ions in the fibers, and found them to follow the order...

Chemical composition of processed bamboo for structural applications

Natural materials are a focus for development of low carbon products for a variety of applications. To utilise these materials, processing is required to meet acceptable industry standards. Laminated bamboo is a commercial product that is currently being explored for structural applications, however there is a gap in knowledge about the effects of commercial processing on the...

Regenerated cellulose from N-methylmorpholine N-oxide solutions as a coating agent for paper materials

The objective of the presented research was to determine the influence of cellulose coating, obtained from the cellulose solution in N-Methylmorpholine N-oxide (NMMO), on the structural and mechanical properties of paper. The effect of heating time of paper samples coated with cellulose dissolved in NMMO was also investigated. Depending on the heating time of the coating, a...

Antibacterial composite cellulose fibers modified with silver nanoparticles and nanosilica

In the present research, nanocomposite antibacterial cellulose fibers of Lyocell type modified with nanosilver particles and nanosilica were obtained. Nanosilver particles were generated by the chemical reduction of silver nitrate (AgNO3) in 50% water solution of N-methylmorpholine N-oxide (NMMO), which was applied as a direct cellulose solvent for the production of Lyocell...

Designing cellulose nanofiber surface for high density polyethylene reinforcement

Because of their high mechanical performance, high specific surface area, and high aspect ratio, there is a strong interest in cellulose nanofibers (CNFs) as a reinforcing material for plastics. Although three hydroxyl groups per repeating unit exposed on the surface is a unique characteristic of CNFs, an effective chemical treatment to improve the reinforcing efficiency of CNFs...

Characterisation of time-dependent, statistical failure of cellulose fibre networks

Cellulosic materials have special advantages for transport packaging, because of their light-weight and recyclable natures and also relatively high specific strength. The strength of such materials is normally evaluated by applying monotonically increasing, quasi-static displacement (or load). However, in real circumstances, the material is subjected to far more complex loading...

Preparation and evaluation of high-lignin content cellulose nanofibrils from eucalyptus pulp

High Klason lignin content (23 wt%) cellulose nanofibrils (LCNF) were successfully isolated from eucalyptus pulp through catalyzed chemical oxidation, followed by high-pressure homogenization. LCNFs had a diameter of ca. 13 nm according to AFM evaluation. Dense films were obtained through vacuum filtration (nanopaper) and subjected to different drying methods. When drying under...

Optimizing the yield and physico-chemical properties of pine cone cellulose nanocrystals by different hydrolysis time

Cellulose nanocrystals (CNCs) were isolated for the first time from pine cones (PC) by alkali and bleaching treatments and subsequent sulfuric acid hydrolysis (64%) at 45 °C. The influence of the hydrolytic reaction time (30, 45, and 90 min) on the yield, chemical composition and structure, and thermal stability of CNCs was evaluated. The removal of non-cellulosic constituents...

All cellulose electrospun water purification membranes nanotextured using cellulose nanocrystals

Cellulose acetate (CA) fibers were electrospun on a mesh template to create specific surface and pore structures for membrane applications. The mesh template CA fiber mats were impregnated with cellulose nanocrystals at varying weight percentages. The membranes showed nanotextured surfaces and improved mechanical properties post impregnation. More importantly, the hydrophilicity...

Tailoring flame-retardancy and strength of papers via layer-by-layer treatment of cellulose fibers

The layer-by-layer (LbL) technology was used to adsorb polyelectrolyte multilayers consisting of cationic polyethylenimine (PEI) and anionic sodium hexametaphosphate (SHMP) onto cellulose fibers in order to enhance the flame-retardancy and tensile strength of paper sheets made from these fibers. The fundamental effect of PEI molecular mass on the build-up of the multilayer film...

The structure of galactoglucomannan impacts the degradation under alkaline conditions

Galactoglucomannan (GGM) from spruce was studied with respect to the degradation behavior in alkaline solution. Three reference systems including galactomannan from locust bean gum, glucomannan from konjac and the linear water-soluble carboxymethyl cellulose were studied with focus on molecular weight, sugar composition, degradation products, as well as formed oligomers, to...

Electroosmotic dewatering of cellulose nanocrystals

One of the main challenges for industrial production of cellulose nanocrystals is the high energy demand during the dewatering of dilute aqueous suspensions. It is addressed in this study by utilising electroosmotic dewatering to increase the solid content of suspensions of cellulose nanocrystals. The solid content was increased from 2.3 up to 15.3 wt%, i.e. removal of more than...

Influence of relative humidity on the strength of hardwood and softwood pulp fibres and fibre to fibre joints

Cellulosic materials are highly sensitive towards environmental changes such as temperature and especially towards humidity. Besides morphological changes like swelling and/or shrinking, the mechanical properties of pulp fibres and fibre to fibre joints change as well. The current study sets to elucidate the changes and the extent to which elevated or decreased relative humidity...

Water repellency improvement of cellulosic textile fibers by betulin and a betulin-based copolymer

Betulin is a naturally abundant and hydrophobic compound in the outer bark of birch and can readily be obtained by solvent extraction. Here, solutions of betulin were used to treat cotton fabrics and improve their water repellency. Cotton fabric impregnated in a solution of betulin in ethanol showed a contact angle for water of approximately 153° and reached a water repellency...

Sulfonated nanocellulose beads as potential immunosorbents

Herein 2,3-dialdehyde cellulose beads prepared from Cladophora green algae nanocellulose were sulfonated and characterized by FTIR, conductometric titration, elemental analysis, SEM, ζ-potential, nitrogen adsorption–desorption and laser diffraction, aiming for its application as a potential immunosorbent material. Porous beads were prepared at mild reaction conditions in water...

Transformation of Miscanthus and Sorghum cellulose during methane fermentation

The purpose of the paper is designation of the changes in the structure of cellulose after the methane fermentation process of Miscanthus and Sorghum harvested during the growing season and afterwards. The percentage and structure of cellulose before and after fermentation were studied. Investigations into changes of the cellulose structure were conducted by the SEC, FT-IR and...

Paper material containing Ag cations immobilised in faujasite: synthesis, characterisation and antibacterial effects

The study is devoted to manufacturing and characterising a new paper material with antimicrobial properties, as an alternative to paper containing silver nanoparticles (NPs) which are claimed to be harmful to the ecosphere. In place of silver NPs, the new material contains faujasite mineral (from the faujasite group) exchanged with silver cations which are firmly attached to the...

Aqueous morpholine pre-treatment in cellulose nanofibril (CNF) production: comparison with carboxymethylation and TEMPO oxidisation pre-treatment methods

In this study, pulped cellulose fibres were pre-treated with aqueous morpholine prior to mechanical disruption in the production of cellulose nanofibrils (CNF). The properties of the morpholine pre-treated CNF (MCNF) were closely compared with CNF obtained from carboxymethylation (CMCNF) and TEMPO-oxidation (TCNF) pre-treatment methods. An investigation of the swelling behaviours...

Thermal conductivity of hygroscopic foams based on cellulose nanofibrils and a nonionic polyoxamer

Nanocellulose-based lightweight foams are promising alternatives to fossil-based insulation materials for energy-efficient buildings. The properties of cellulose-based materials are strongly influenced by moisture and there is a need to assess and better understand how the thermal conductivity of nanocellulose-based foams depends on the relative humidity and temperature. Here, we...

Modulating cell response on cellulose surfaces; tunable attachment and scaffold mechanics

Combining surface chemical modification of cellulose to introduce positively charged trimethylammonium groups by reaction with glycidyltrimethylammonium chloride (GTMAC) allowed for direct attachment of mammalian MG-63 cells, without addition of protein modifiers, or ligands. Very small increases in the surface charge resulted in significant increases in cell attachment: at a...

Effect of xylanases on refining process and kraft pulp properties

Results of this study demonstrate that enzymatic pretreatment of pulps enables energy savings in the refining process. Pretreatments of NBSK pulp with 3 different commercial xylanases resulted in a faster increase in the pulp freeness that reduced energy input for refining. The partial xylan removal by these enzymes affected the properties of cellulosic pulp and paper. The...