Moderate surface acetylation of nanofibrillated cellulose for the improvement of paper strength and barrier properties

RSC Advances ◽  
2015 ◽  
Vol 5 (74) ◽  
pp. 60179-60187 ◽  
Author(s):  
Mozhdeh Mashkour ◽  
Elyas Afra ◽  
Hossein Resalati ◽  
Mahdi Mashkour
Keyword(s):  
Barrier Properties ◽  
Nanofibrillated Cellulose ◽  
Paper Strength ◽  
Surface Acetylation

This study evaluated the effect of using acetylated nanofibrillated cellulose (ANFC) and acetylated pulp (AP) fibers to modify strength and barrier properties of paper.

scholarly journals Getting Environmentally Friendly and High Added-Value Products from Lignocellulosic Waste

2021 ◽  
Author(s):  
Elizabeth Quintana Rodríguez ◽  
Domancar Orona Tamayo ◽  
José Nicacio González Cervantes ◽  
Flora Itzel Beltrán Ramirez ◽  
María Alejandra Rivera Trasgallo ◽  
...  
Keyword(s):  
Value Added ◽  
Environmentally Friendly ◽  
Barrier Properties ◽  
Nanofibrillated Cellulose ◽  
Global Market ◽  
Added Value ◽  
Lignocellulosic Waste ◽  
Potential Applications ◽  
Cellulose Nanomaterials ◽  
Micro Nanofibrillated Cellulose

In recent years, alternatives have been sought for the reuse of lignocellulosic waste generated by agricultural and other industries because it is biodegradable and renewable. Lignocellulosic waste can be used for a wide variety of applications, depending on their composition and physical properties. In this chapter, we focus on the different treatments that are used for the extraction of natural cellulose fibers (chemical, physical, biological methods) for more sophisticated applications such as reinforcement in biocomposites. Due to the different morphologies that the cellulose can present, depending from sources, it is possible to obtain cellulose nanocrystals (CNCs), micro- nanofibrillated cellulose (MFC/NFC), and bacterial nanocellulose (BNC) with different applications in the industry. Among the different cellulose nanomaterials highlighted characteristics, we can find improved barrier properties for sound and moisture, the fact that they are environmentally friendly, increased tensile strength and decreased weight. These materials have the ability to replace metallic components, petroleum products, and nonrenewable materials. Potential applications of cellulose nanomaterials are present in the automotive, construction, aerospace industries, etc. Also, this chapter exhibits global market predictions of these new materials or products. In summary, lignocellulosic residues are a rich source of cellulose that can be extracted to obtain products with high value-added and eco-friendly characteristics.

Wet-end addition of nanofibrillated cellulose pretreated with cationic starch to achieve paper strength with less refining and higher bulk

TAPPI Journal ◽  
2018 ◽  
Vol 17 (07) ◽  
pp. 395-403 ◽  
Author(s):  
Matthew Rice ◽  
Lokendra Pal ◽  
Ronalds Gonzalez ◽  
Martin Hubbe
Keyword(s):  
Apparent Density ◽  
Colloidal Silica ◽  
Nanofibrillated Cellulose ◽  
Dry Mass ◽  
High Mass ◽  
Paper Strength ◽  
Cationic Starch ◽  
Combined System ◽  
Bonding System ◽  
High Level

Nanofibrillated cellulose (NFC) treated with cationic starch was evaluated as a bonding system to permit lower degrees of refining and lower apparent density of high-mass handsheets made from bleached kraft pulp. Mixed pulp (70% hardwood, 30% softwood) was formed into sheets with the optional addition of 5% by dry mass of NFC. The default addition of NFC was compared with a system in which the NFC had been pretreated either with cationic starch (at various levels) or optionally followed by colloidal silica. Comparative tests also were carried out with separate addition of cationic starch to the main furnish. Unrefined fibers (514 mL CSF) were compared with low-refined (473 mL CSF) and high-refined (283 mL CSF) pulp mixtures. The NFC that had been pretreated with cationic starch at a high level was especially effective at boosting the tensile strength and stiffness of sheets prepared from pulp that had been refined at a low level, thus achieving improved strength at relatively low apparent density (high bulk) of the handsheets. The results support a strategy, for applicable grades of paper, of using cationic starchpretreated NFC in place of refining energy applied to the main fiber furnish. It was further established that colloidal silica can be employed as a further pretreatment of the cationic starch–treated NFC as a means of promoting dewatering in the combined system.

Effect of nanofibrillated cellulose made from enzyme-pretreated bamboo pulp on paper strength

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 964-978
Author(s):  
Hae Min Jo ◽  
Ji Young Lee ◽  
Su Ho Kim ◽  
Yeon Hui Lee
Keyword(s):  
Physical Properties ◽  
Kraft Pulp ◽  
Nanofibrillated Cellulose ◽  
Raw Material ◽  
Paper Strength ◽  
Strength Enhancement ◽  
Tensile Index ◽  
Similar Improvement ◽  
Bamboo Pulp ◽  
Enzyme Pretreatment

The applicability of bleached bamboo kraft pulp (Ba-BKP) was explored as a raw material for the manufacture of nanofibrillated cellulose (EN-NFC) made of enzyme-pretreated pulps and the effects of the EN-NFC on enhancing paper strength. The Ba-BKP was pretreated using an endo-glucanase enzyme at 50 °C and pH 6, after which the EN-NFC was made by micro-grinding. Bleached hardwood kraft pulp (Hw-BKP) was used as a control, and the non-enzymatic refining pretreatment of BKPs was compared with the enzyme pretreatment. The EN-NFC was incorporated into handsheets, and the sheet strengths were measured. The physical properties of the NFC made from the Ba-BKP were similar to those made from the Hw-BKP. The NFC prepared following enzyme pretreatment were smaller and more uniform than those pretreated with refining. The EN-NFC made from the Ba-BKP was effective at enhancing tensile index by 52.7%, and burst index by 210.2% when 2% of EN-NFC was added in the furnish, and those of handsheets containing the EN-NFC made from Hw-BKP showed the similar improvement. Therefore, Ba-BKP can be used as a raw material for the manufacture of EN-NFC that confers similar physical properties and strength enhancement to paper as those made from Hw-BKP.

Sugar Palm Nanofibrillated Cellulose Fibre Reinforced Sugar Palm Starch Nanocomposite. Part 1: Morphological, Mechanical and Physical Properties

2018 ◽  
Author(s):  
R.A. Ilyas ◽  
S.M. Sapuan ◽  
M.R. Ishak ◽  
E.S. Zainudin
Keyword(s):  
Colloidal Suspension ◽  
Cellulose Fibre ◽  
Barrier Properties ◽  
Nanofibrillated Cellulose ◽  
Short Life ◽  
Water Barrier ◽  
Mechanical And Physical Properties ◽  
Ft Ir ◽  
Ir Analysis ◽  
Barrier Resistance

Environmentally friendly starch bionanocomposites were successfully casted using a colloidal suspension of sugar palm nanofibrillated cellulose (SPNFCs) as a nanofiller to reinforce sugar palm starch (SPS). The SPNFCs, having diameters of 5.5±0.99 nm and length of several micrometer, were prepared from sugar palm fibres via high pressurized homogenization process. The dependence of morphology and properties of the SPS-based bionanocomposites on SPNFCs content ranging from 0 to 1.0 wt. % was investigated by FESEM, as well as measurements of physical, mechanical and water barrier properties. FESEM investigation displayed good miscibility between SPS and SPNFCs. FT-IR analysis confirmed that SPS and SPNFCs were compatible and inter-molecular hydrogen bonds existed between them. The SPS/SPNFCs-1.0, has undergone increment in both tensile strength and Young’s modulus for SPS film from 4.80 MPa to 10.68 MPa and from 53.97 MPa to 121.26 MPa, respectively. Reinforcing SPNFCs into SPS matrix led to an improvement in water barrier resistance for the resulting bionanocomposites. Overall, the incorporation of SPNFCs with SPS composites enhances the properties of the bionanocomposites for short-life application; that is, disposable container, plastic packaging, etc.

scholarly journals Improving recycling of polyethylene-coated paperboard with a nanofibrillated cellulose layer

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3285-3297
Author(s):  
Mohammed Z. Al-Gharrawi ◽  
Jinwu Wang ◽  
Douglas W. Bousfield
Keyword(s):  
Polymer Film ◽  
Adhesive Strength ◽  
Barrier Properties ◽  
Nanofibrillated Cellulose ◽  
Air Permeability ◽  
Pressing Pressure ◽  
Pulp Fibers ◽  
Good Separation ◽  
Pressing Time ◽  
Model Predictions

To improve the ability to recycle polyethylene (PE)-coated paperboard, one solution may be to use nanofibrillated cellulose (NFC) to generate a layer that should weaken when wet that leads to a clean separation between the polymer film and the pulp fibers. This NFC layer has the potential to improve the package’s oxygen and grease barrier properties, but this system has not been explored in the literature. In this study, papers coated with zero, 2, and 4 g/m2 of NFC were laminated with a PE film under a range of pressing temperatures and times at a constant pressing pressure. A model was developed to predict fiber recovery given the air permeability of the paper, pressing time, polymer temperature, and paper void volume. The recyclability or fiber recovery was evaluated in addition to the adhesive strength. Samples with the NFC layer had much improved fiber recovery because the NFC layer gives a good separation during the recycling operation. The model predictions were compared to the experiments.

scholarly journals Improved Process to Obtain Nanofibrillated Cellulose (CNF) Reinforced Starch Films with Upgraded Mechanical Properties and Barrier Character

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1071 ◽  
Author(s):  
Luis Angel Granda ◽  
Helena Oliver-Ortega ◽  
Maria José Fabra ◽  
Quim Tarrés ◽  
Maria Àngels Pèlach ◽  
...  
Keyword(s):  
Composite Films ◽  
High Capacity ◽  
Water Vapor Permeability ◽  
Barrier Properties ◽  
Thermoplastic Starch ◽  
Nanofibrillated Cellulose ◽  
Vapor Permeability ◽  
The Matrix ◽  
Starch Films ◽  
The One

Nowadays, the interest on nanofibrillated cellulose (CNF) has increased owing to its sustainability and its capacity to improve mechanical and barrier properties of polymeric films. Moreover, this filler shows some drawbacks related with its high capacity to form aggregates, hindering its dispersion in the matrix. In this work, an improved procedure to optimize the dispersability of CNF in a thermoplastic starch was put forward. On the one hand, CNF needs a hydrophilic dispersant to be included in the matrix, and on the other, starch needs a hydrophilic plasticizer to obtain a thermoformable material. Glycerol was used to fulfil both targets at once. CNF was predispersed in the plasticizer before nanofibrillation and later on was included into starch, obtaining thin films. The tensile strength of these CNF–starch composite films was 60% higher than the plain thermoplastic starch at a very low 0.36% w/w percentage of CNF. The films showed a noticeable correlation between water uptake, and temperature and humidity. Regarding permeability, a ca. 55% oxygen and water vapor permeability drop was found by nanofiller loading. The hydrolytic susceptibility of the composite was confirmed, being similar to that of the thermoplastic starch.

Sugar palm ( Arenga pinnata [ Wurmb .] Merr ) starch films containing sugar palm nanofibrillated cellulose as reinforcement: Water barrier properties

2019 ◽  
Vol 41 (2) ◽  
pp. 459-467 ◽  
Author(s):  
R. A. Ilyas ◽  
S. M. Sapuan ◽  
A. Atiqah ◽  
Rushdan Ibrahim ◽  
Hairul Abral ◽  
...  
Keyword(s):  
Barrier Properties ◽  
Nanofibrillated Cellulose ◽  
Water Barrier ◽  
Starch Films

Organization of tight junctions in the choroid plexus epithelium

1978 ◽  
Vol 36 (2) ◽  
pp. 336-337
Author(s):  
B. Van Deurs ◽  
J. K. Koehler
Keyword(s):  
Choroid Plexus ◽  
Present Report ◽  
Freeze Fracture ◽  
Barrier Properties ◽  
Cell Junctions ◽  
Structural Basis ◽  
Apical Surface ◽  
Choroid Plexus Epithelium ◽  
Solid Nitrogen ◽  
Special Composition

The choroid plexus epithelium constitutes a blood-cerebrospinal fluid (CSF) barrier, and is involved in regulation of the special composition of the CSF. The epithelium is provided with an ouabain-sensitive Na/K-pump located at the apical surface, actively pumping ions into the CSF. The choroid plexus epithelium has been described as “leaky” with a low transepithelial resistance, and a passive transepithelial flux following a paracellular route (intercellular spaces and cell junctions) also takes place. The present report describes the structural basis for these “barrier” properties of the choroid plexus epithelium as revealed by freeze fracture.Choroid plexus from the lateral, third and fourth ventricles of rats were used. The tissue was fixed in glutaraldehyde and stored in 30% glycerol. Freezing was performed either in liquid nitrogen-cooled Freon 22, or directly in a mixture of liquid and solid nitrogen prepared in a special vacuum chamber. The latter method was always used, and considered necessary, when preparations of complementary (double) replicas were made.

Growth of near noble metal Pd and Pt thin film silicides morphology and structure

1984 ◽  
Vol 42 ◽  
pp. 498-499
Author(s):  
E. I. Alessandrini ◽  
M. O. Aboelfotoh
Keyword(s):  
Noble Metals ◽  
Annealing Temperature ◽  
Chemical Compounds ◽  
Barrier Properties ◽  
Solid State Reactions ◽  
Transmission Electron ◽  
Stable Chemical ◽  
Metal Thickness ◽  
Amorphous Si ◽  
Si Films

Considerable interest has been generated in solid state reactions between thin films of near noble metals and silicon. These metals deposited on Si form numerous stable chemical compounds at low temperatures and have found applications as Schottky barrier contacts to silicon in VLSI devices. Since the very first phase that nucleates in contact with Si determines the barrier properties, the purpose of our study was to investigate the silicide formation of the near noble metals, Pd and Pt, at very thin thickness of the metal films on amorphous silicon.Films of Pd and Pt in the thickness range of 0.5nm to 20nm were made by room temperature evaporation on 40nm thick amorphous Si films, which were first deposited on 30nm thick amorphous Si3N4 membranes in a window configuration. The deposition rate was 0.1 to 0.5nm/sec and the pressure during deposition was 3 x 10 -7 Torr. The samples were annealed at temperatures in the range from 200° to 650°C in a furnace with helium purified by hot (950°C) Ti particles. Transmission electron microscopy and diffraction techniques were used to evaluate changes in structure and morphology of the phases formed as a function of metal thickness and annealing temperature.

Changes in corneocyte element concentrations occur in skin inner stratum corneum

1990 ◽  
Vol 48 (2) ◽  
pp. 146-147
Author(s):  
R. R. Warner
Keyword(s):  
Stratum Corneum ◽  
Human Skin ◽  
Element Concentration ◽  
Skin Barrier ◽  
Barrier Properties ◽  
Brick Wall ◽  
Inorganic Elements ◽  
Dry Skin ◽  
Skin Biopsies ◽  
Intercellular Lipid

Keratinocytes undergo maturation during their transit through the viable layers of skin, and then abruptly transform into flattened, anuclear corneocytes that constitute the cellular component of the skin barrier, the stratum corneum (SC). The SC is generally considered to be homogeneous in its structure and barrier properties, and is often shown schematically as a featureless brick wall, the “bricks” being the corneocytes, the “mortar” being intercellular lipid. Previously we showed the outer SC was not homogeneous in its composition, but contained steep gradients of the physiological inorganic elements Na, K and Cl, likely originating from sweat salts. Here we show the innermost corneocytes in human skin are also heterogeneous in composition, undergoing systematic changes in intracellular element concentration during transit into the interior of the SC.Human skin biopsies were taken from the lower leg of individuals with both “good” and “dry” skin and plunge-frozen in a stirred, cooled isopentane/propane mixture.

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