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The kinetics and products of cellulose pyrolysis can be studied using large-scale molecular dynamics simulations at high temperatures, where the reaction rates are high enough to make the simulation times practical. We carried out molecular dynamics simulations employing the ReaxFF reactive force field to study the initial step of the thermal decomposition process. We gathered statistics of simulated...
Thermomechanical pulp (TMP) produced using atmospheric refining was ground to isolate lignocellulose nanofibrils (LCNF). Forty minutes and a specific energy of about 1300 kWh/t were necessary to reach the end-point of the process defined by the presence of 95% fines in the slurry. 100% fines were reached after 90 min and 5800 kWh/t. The similarity in structure between pilot-scale produced reference...
The precipitation of micro- and nanoparticles of calcium carbonate onto lignocellulosic microfibers was investigated at different microfiber concentrations with and without polyacrylic acid (PAA), i.e. a polymer commonly used to form polymer-induced liquid precursors of CaCO3. Concentrations of PAA, Ca(OH)2, CO2 and microfiber were varied in order to study the impact of reaction conditions on PCC...
Cellulose-based lotus-leaf-like filter paper for selective separation of oil/water was prepared. Experimentally, cellulose nanofibril aerogel microspheres prepared by ultrasonic atomization method were coated on commercial filter papers to form unique “micro–nano” structured surface. By controlling both the morphology and chemistry of the surface, the papers could be either under-water superoleophobic...
Cationization of cotton brings advantages in the reactive dyeing process, such as eliminating the use of electrolytes and increasing color yield. However, high dye strike rates caused by the electronic attractions between anionic dyes and cationized cotton may result in poor levelness of dyeing, especially for light shades. For some monochloritriazine–monochloritriazine homobifunctional reactive dyes,...
For the first time, we report a facile method for the development of a novel, non-toxic, self-healing, as well as X-ray radiation shielding smart gel (NSSH gel). The smart gel has been developed by chemically designing and mineralogically formulating the various precursors inherently present in red mud based compositions and hydrogel matrix containing nanosized glycerolates of metallic oxide ceramic...
Lignocellulosic fibers, which are abundant and biodegradable, have shown great application potential in many fields. The fiber charge, which characterizes the amount of acidic groups in lignocellulosic fiber, can have an important effect on the fiber performance during papermaking, ultimately affecting the architecture of fibrous matrices. In this study, carboxylic acid groups were installed using...
This work aims to reuse bromelain, a cysteine protease isolated from stems of pineapples, and to improve its thermal stability by immobilization onto gauze-reinforced regenerated cellulose (RC) fibers. To obtain RC fibers (358 ± 53 nm), cellulose acetate (CA, M.W. ∼3 × 104 g/mol) fibers (307 ± 59 nm) were electrospun from 17% w/w CA mixed with 5% w/w Tween 80 in acetic acid: water of 3:1 by weight...
Hydrochars in situ functionalized with –SO3H groups were generated from kenaf core via a low-temperature hydrothermal carbonization process of 105 °C with a consecutive catalysis of H2SO4. The micro-morphology of the hydrochars was strongly affected by the sulfuric acid concentration. Sphere-like particles with size varying between 200 nm and 1 μm were obtained when the acid concentration was 52 wt%...
Cellulose nanofibers (CNF) have increasing relevance in different applications, for instance, in the paper industry as a sustainable strength additive. This application is especially beneficial for recycled paper, which reaches higher product quality despite its limitations. CNF change paper properties and also can affect the production process, especially the drainage stage, in which retention additives...
Cellulose nanofibers (CNF) have been suggested in the literature as a potential barrier coating layer for paper and paperboard. However, due to its rheological properties and solids content, the material is difficult to apply to paper at significant coat weight levels. The use of CNF as a coating to improve the structure and barrier properties of paperboard was investigated. Two forms of CNF were...
Polylactide (PLA)/cellulose nanofiber (CNF) biocomposites were prepared via solution casting and direct melt mixing. To improve the compatibility, a masterbatch of CNFs and poly(ethylene glycol) (PEG) (1:2) was also prepared. The effects of PEG on the morphology and properties of the biocomposites were investigated. The dispersion/distribution of nanofibers in PLA was improved when the masterbatch...
Spraying of nanocellulose (NC) on a solid surface to prepare films is an alternative technique to vacuum filtration, which requires a long drainage time and produces films which can sometimes be difficult to separate from the filter. This letter reports a rapid preparation technique for nano-cellulose films using a bench scale system spray coating nanocellulose suspension onto stainless steel plates...
Crosslinked poly(vinyl alcohol) (PVA)/cellulose nanofibril (CNF) hybrid aerogel micro-spheres with two different particle sizes were fabricated via a combination of the water-in-oil (W/O) emulsification process and the freeze-drying process. The aerogel micro-spheres were highly porous with a bulk density as low as 0.0047 g/cm3 for the large microspheres. The pore size of the microspheres ranged from...
Cellulose acetylation has been reported as a side reaction of cellulose treatment with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIm][OAc]) (Karatzos et al. in Cellulose 19:307–312, 2012) and other 1,3-dialkylimidazolium acetate ionic liquids. 1-Acetylimidazole (AcIm), an [EMIm][OAc] impurity, has been found to be the actual acetylating agent (Zweckmair et al. in Cellulose 22:3583–3596,...
Cross-linked cellulose nanofibril (CNF) aerogel with positive and negative surface charge was prepared. For the surface charge modification of CNF from its intrinsic negative charge to positive charge, glycidyltrimethylammonium chloride was used. To stabilize the network structure of CNF aerogel in aqueous condition, maleic acid and sodium hypophosphite cross-linking treatment was applied. The ion...
Cellulose nanocrystals were successfully oxidized with sodium hypochlorite using catalytic amounts of sodium bromide and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical at pH 10 in water. Carboxylate groups were selectively introduced at the surface of the crystals up to a total acid content of 1200 mmol kg−1 without damaging the integrity of the crystals. The final acid content can easily be...
Due to the importance in economic and environmental benefits, marine biomass has gained increasing attention in recent years. In this work, marine biomass-based materials were prepared and characterized. Highly reinforcing cellulose nanocrystals (CNCs) with length of 1–2 μm and aspect ratio of ~75 were extracted from tunicates (t-CNCs), and CNCs with length of 100–300 nm and aspect ratio of ~15 from...
A novel intumescent flame retardant treatment, consisting of vinylphosphonic acid (VPA) as the acid source and methacrylamide (MAA) as blowing agent, was designed and applied onto cotton fabrics. The grafting of reactive monomers onto cellulose chains was carried out using potassium persulfate as initiator of a radical polymerization technique. The thermal and fire behaviour of the treated fabrics...
The objective of this study was to develop nanofibrillated cellulose (NFC)-based substrate for rapid detection of melamine in milk by surface-enhanced Raman spectroscopy (SERS). NFC were served as a highly porous platform to load with gold nanoparticles (AuNPs), which can be used as a flexible SERS substrate with nanoscale roughness to generate strong electromagnetic field in SERS measurement. The...
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