# Cellulose

## List of Papers (Total 149)

#### Dielectric losses in the composite cellulose–mineral oil–water nanoparticles: theoretical assumptions

The paper presents an analysis of test results by Frequency Domain Spectroscopy (FDS) of the loss tangent (tgδ) in electrotechnical pressboard impregnated with insulating oil and containing nanoparticles of water depending on the frequency of alternating current, sample temperature and degree of moisture. We found tgδ reduction in areas of low and ultra-low frequency. It is ...

#### Why do we observe significant differences between measured and ‘back-calculated’ properties of natural fibres?

The drive towards sustainability, even in materials technologies, has fuelled an increasing interest in bio-based composites. Cellulosic fibres, such as flax and jute, are being considered as alternatives to technical synthetic fibres, such as glass, as reinforcements in fibre reinforced polymer composites for a wide range of applications. A critical bottleneck in the advancement ...

#### Microwave-assisted TiO2: anatase formation on cotton and viscose fabric surfaces

The method of TiO2-anatase film preparation on cotton and viscose fabric surfaces using the sol-gel process and microwave treatment is presented. Microwave treatment was used to change the amorphous TiO2 form to anatase directly on the fabrics. The influence of microwave treatment conditions on the obtainable polymorphic form of TiO2 was examined. Fabrics were pretreated with ...

#### Characterizations of biodegradable epoxy-coated cellulose nanofibrils (CNF) thin film for flexible microwave applications

Wood pulp cellulose nanofibrils (CNF) thin film is a novel recyclable and biodegradable material. We investigated the microwave dielectric properties of the epoxy coated-CNF thin film for potential broad applications in flexible high speed electronics. The characterizations of dielectric properties were carried out in a frequency range of 1–10 GHz. The dielectric constant and loss ...

#### Visualization of structural changes in cellulosic substrates during enzymatic hydrolysis using multimodal nonlinear microscopy

Enzymatic hydrolysis of cellulose provides a renewable source of monosaccharides for production of variety of biochemicals and biopolymers. Unfortunately, the enzymatic hydrolysis of cellulose is often incomplete, and the reasons are not fully understood. We have monitored enzymatic hydrolysis in terms of molecular density, ordering and autofluorescence of cellulose structures in ...

#### Coarse-grained model of the native cellulose $\hbox {I}\alpha$ and the transformation pathways to the $\hbox {I}\beta$ allomorph

All-atom simulations are used to derive effective parameters for a coarse-grained description of the crystalline cellulose $\hbox {I}\alpha$. In this description, glucose monomers are represented by the C4 atoms and non-bonded interactions within the cellulose sheets and between the sheets by effective Lennard-Jones interactions. The parameters are determined by two methods: the ...

#### Impact of selected solvent systems on the pore and solid structure of cellulose aerogels

The impact of selected cellulose solvent systems based on the principal constituents tetrabutylammonium fluoride (TBAF), 1-ethyl-3-methyl-1H-imidazolium-acetate, N-methylmorpholine-N-oxide, or calcium thiocyanate octahydrate (CTO) on the properties of cellulose II aerogels prepared from these solvent systems has been investigated as a means towards tailoring cellulose aerogel ...

#### Dry, hydrophobic microfibrillated cellulose powder obtained in a simple procedure using alkyl ketene dimer

In order to produce dry and hydrophobic microfibrillated cellulose (MFC) in a simple procedure, its modification with alkyl ketene dimer (AKD) was performed. For this purpose, MFC was solvent-exchanged to ethyl acetate and mixed with AKD dissolved in the same solvent. Curing at 130 °C for 20 h under the catalysis of 1-methylimidazole yielded a dry powder. Scanning electron ...

#### Direct preparation of green and renewable aerogel materials from crude bagasse

Lignocellulosic biomass aerogels with relatively high Brunauer–Emmett–Teller (BET) surface area and pore volume were prepared directly from bagasse solutions in the present study. Bagasse was dissolved in DMSO/LiCl, treated with cyclic freezing-thawing processes, and regenerated with water. The resulted bagasse hydrogels were solvent-exchanged to t-butanol and subjected to ...

#### Aqueous solutions of HEC and hmHEC: effects of molecular mass versus hydrophobic associations on hydrodynamic and thermodynamic parameters

Aqueous solutions of amphiphilic polymers usually comprise of inter- and intramolecular associations of hydrophobic groups often leading to a formation of a rheologically significant reversible network at low concentrations that can be identified using techniques such as static light scattering and rheometry. However, in most studies published till date comparing water soluble ...

#### Extensional rheometry of cellulose ether solutions: flow instability

Capillary breakup extensional rheometry of semi-dilute hydroxyethyl cellulose (HEC) solutions was performed under several step-stretch conditions. The resulting parameters, i.e. terminal steady state extensional viscosity (η E ) and the timescale for viscoelastic stress growth, commonly referred to as the extensional relaxation time (λ E ) were found to be sensitive to the ...

#### Bio polyetherurethane composites with high content of natural ingredients: hydroxylated soybean oil based polyol, bio glycol and microcrystalline cellulose

In our study, we focused on obtaining bio-polyurethane composites using bio-components such as bio glycol, modified natural oil-based polyol, and microcrystalline cellulose (MCC). The pre-polymer method was used to prepare the bio polyurethane matrix. Prepolymer was synthesized using 4,4′-diphenylmethane diisocyanate and a polyol mixture containing 50 wt% of commercial polyether ...

#### Evaluation of pine kraft cellulosic pulps and fines from papermaking as potential feedstocks for biofuel production

Results of enzymatic hydrolysis of pine kraft cellulosic pulps (Kappa numbers ranging from 17.2 to 86.2) and waste fines from paper production line suggest that they are potential feedstocks for biofuel production. Glucose (61–68 % d.w.) and reducing sugars (around 90 % d.w.) yields from the pine cellulosic pulps with Kappa numbers ranging between 17.2 and 47.7 were higher than ...

#### Permittivity of a composite of cellulose, mineral oil, and water nanoparticles: theoretical assumptions

The paper presents results of testing permittivity of an oil-impregnated electric pressboard containing water nanoparticles depending on AC frequency, moisture content level and the temperature of samples. A new method has been developed for converting experimentally obtained frequency dependences of permittivity determined with the frequency-domain spectroscopy (FDS) to the ...

#### Preparation of cross-linked cellulose nanofibril aerogel with water absorbency and shape recovery

Cellulose nanofibril (CNF) aerogels are promising materials for various applications because of their highly porous and ultralight characteristics. The fiber network of CNF aerogels held together by hydrogen bonding and mechanical entanglement of adjacent fibers is easily destroyed when it is exposed to water. In this study, cross-linked CNF aerogels were prepared using maleic acid ...

#### Electrochemical deposition of silver nanoparticle and polymerization of pyrrole on fabrics via conducting multiwall carbon nanotubes

The paper presents results of tests on the possibility of utilising fabric with a deposited spatial network of multiwall carbon nanotubes (MWCNTs) as electrodes in processes of their functionalization by electrochemical methods enabling deposition of metal nanoparticles, as well as—by electropolymerization—of conductive polymer nanocoatings. Cyclic voltammetry was employed in the ...

#### Biocomposites of polyamide 4.10 and surface modified microfibrillated cellulose (MFC): influence of processing parameters on structure and thermomechanical properties

Novel bio-polyamides obtained from renewable resources, e.g. PA4.10, are considered nowadays as promising ‘green’ engineering materials consisting of building blocks derived from castor oil. In this work the composites of heterogeneously acetylated microfibrillated cellulose (MFC) and biopolyamide 4.10 have been prepared by melt blending. Thermoplastic processing of PA4.10/MFC ...

#### Comparison of digestibility of wood pulps produced by the sulfate and TMP methods and woodchips of various botanical origins and sizes

Poplar and pine cellulosic pulps derived by the sulfate process (Kappa numbers of 15.4 and 31.4, respectively) and a poplar thermomechanical pulp (TMP, Kappa number of 124.7) as well as 0.43–0.8 mm woodchips of various botanical origins (poplar, birch, lime, oak, beech, pine, and spruce) and poplar chips of five different average particle sizes, ranging from 1.6–2.0 to <0.43 mm, ...

#### Development of cardanol-bonded cellulose thermoplastics: high productivity achieved in two-step heterogeneous process

We developed a heterogeneous process with low energy consumption to synthesize novel high-strength and heat-resistant cellulose-based bioplastics: cellulose esters bonded with a short chain component (acetic acid) and a long one (3-pentadecylphenoxy acetic acid; PAA), which is a derivative of cardanol, extracted from cashew nut shells. Although we recently showed that PAA-bonded ...

#### Breakdown of hierarchical architecture in cellulose during dilute acid pretreatments

Cellulose is an attractive candidate as a feedstock for sustainable bioenergy because of its global abundance. Pretreatment of biomass has significant influence on the chemical availability of cellulose locked in recalcitrant microfibrils. Optimizing pretreatment depends on an understanding of its impact on the microscale and nanoscale molecular architecture. X-ray scattering ...