Role of cellulose nanofibrils in improving the strength properties of paper: a review

Cellulose ◽  
2021 ◽  
Author(s):  
Thabisile Brightwell Jele ◽  
Prabashni Lekha ◽  
Bruce Sithole
Keyword(s):  
Cellulose Nanofibrils ◽  
Strength Properties

scholarly journals Role of Cellulose Nanofibrils in Improving the Strength Properties of Papers: A Review

2021 ◽  
Author(s):  
Thabisile Brightwell Jele ◽  
Prabashni Lekha ◽  
Bruce Sithole
Keyword(s):  
Cellulose Nanofibrils ◽  
High Strength ◽  
Barrier Properties ◽  
Strength Properties ◽  
Biochemical Properties ◽  
Factors Affecting ◽  
Tear Index ◽  
Different Types ◽  
Breaking Length

Abstract The pursuit for sustainability in the papermaking industry calls for the elimination or reduction of synthetic additives and the exploration of renewable and biodegradable alternatives. Cellulose nanofibrils (CNFs), due to their inherent morphological and biochemical properties, are an excellent alternative to synthetic additives. These properties enable CNFs to improve the mechanical, functional and barrier properties of different types of paper. The nanosize diameter, micrometre length, semi-crystalline structure, high strength and modulus of CNFs has a direct influence on the mechanical properties of paper such as tensile index, burst index, Scott index, breaking length, tear index, Z-strength, E-modulus, strain at break, and tensile stiffness. This review details the role played by CNFs as an additive to improve strength properties of papers and the factors affecting the improvement in paper quality when CNFs are added as additives. The paper also includes techno-economic aspects of the process and identifies areas that need further research.

SEM Study of Tension Wood Fiber Morphology and its Effect on Paper Properties

1977 ◽  
Vol 35 ◽  
pp. 308-309
Author(s):  
K. W. Robinson
Keyword(s):  
Tension Wood ◽  
Wood Fiber ◽  
Strength Properties ◽  
Fiber Morphology ◽  
Paper Properties ◽  
Pure Cellulose ◽  
Short Rotation ◽  
Hardwood Trees ◽  
Sem Study

Tension wood (TW) is an abnormal tissue of hardwood trees; although it has been isolated from most parts of the tree, it is frequently found on the upper side of branches and leaning stems. TW has been classically associated with geotropic alignment, but more recently it has been associated with fast growth. Paper made from TW is generally lower in strength properties. Consequently, the paper industries' growing dependence on fast growing, short- rotation trees will result in higher amounts of TW in the final product and a corresponding reduction in strength.Relatively few studies have dealt with the role of TW in the structure of paper. It was suggested that the lower strength properties of TW were due to a combination of factors, namely, its unique morphology, compression failures in the cell wall, and lower hemicellulose content. Central to the unique morphology of the TW fiber is the thick gelatinous layer (G-layer) composed almost entirely of pure cellulose.

Influence of the Aggregate Type on the Properties of Dolomitic Lime-Based Mortars

2016 ◽  
Vol 722 ◽  
pp. 343-350 ◽  
Author(s):  
Martin Vyšvařil ◽  
Tomáš Žižlavský ◽  
Patrik Bayer
Keyword(s):  
Positive Impact ◽  
Total Porosity ◽  
Strength Properties ◽  
Carbonation Reaction ◽  
Dolomitic Lime ◽  
Limestone Aggregate ◽  
Lime Mortars ◽  
Restoration Work ◽  
Limestone Fines

Considering the requirement of numerous restoration work on historical buildings with dolomitic lime-based mortars, a research of the applicability and suitability of various types of plasters for repairing the historical plasters have been developed. This work presents the applicability of limestone aggregate and limestone fines to dolomitic lime-based mortars. The role of aggregates on the properties of dolomitic lime mortars was examined by comparing pure quartz sand and limestone aggregate and its quantity in the mortar. Limestone aggregate and limestone fines accelerated the carbonation reaction in the mortars, but the positive impact of limestone aggregates to strength properties of mortars was not observed. Mortars with limestone aggregate showed higher total porosity and water absorption than those with quartz aggregate. Similar results was obtained for mortars with limestone fines. It was found that limestone aggregate and limestone fines, used in this work, is not so suitable and applicable to the dolomitic lime-based mortar as to the aerial lime-based mortars.

Role of Cellulose Nanofibrils in Structure Formation of Pigment Coating Layers

2017 ◽  
Vol 56 (34) ◽  
pp. 9569-9577 ◽  
Author(s):  
Kyudeok Oh ◽  
Jee-Hong Lee ◽  
Wanhee Im ◽  
Araz Rajabi Abhari ◽  
Hak Lae Lee
Keyword(s):  
Structure Formation ◽  
Cellulose Nanofibrils ◽  
Pigment Coating ◽  
Coating Layers

scholarly journals Biomimetic Composites with Enhanced Toughening Using Silk Inspired Triblock Proteins and Aligned Nanocellulose Reinforcements

2019 ◽  
Author(s):  
Pezhman Mohammadi ◽  
A. Sesilja Aranko ◽  
Christopher P. Landowski ◽  
Olli Ikkala ◽  
Kristaps Jaudzems ◽  
...  
Keyword(s):  
Spider Silk ◽  
Cellulose Nanofibrils ◽  
High Strength ◽  
Beta Sheets ◽  
Conformational Switching ◽  
Multiple Length Scales ◽  
The Matrix ◽  
Strength And Stiffness ◽  
Flow Alignment

Silk and cellulose are biopolymers that show a high potential as future sustainable materials.They also have complementary properties, suitable for combination in composite materials where cellulose would form the reinforcing component and silk the tough matrix. Therein, a major challenge concerns balancing structure and properties in the assembly process. We used recombinant proteins with triblock architecture combining structurally modified spider silk with terminal cellulose affinity modules. Flow-alignment of cellulose nanofibrils and triblock protein allowed a continuous fiber production.The protein assembly involved phase separation into concentrated coacervates, with subsequent conformational switching from disordered structures to beta sheets. This gave the matrix a tough adhesiveness, forming a new composite material with high strength and stiffness combined with increased toughness. We show that versatile design possibilities in protein engineering enable new fully biological materials, and emphasize the key role of controlled assembly at multiple length scales for realization.<br>

scholarly journals The role of organic matter in formation of the properties of a shale deposit

2019 ◽  
Vol 484 (2) ◽  
pp. 220-223
Author(s):  
И. Ф. Юсупова
Keyword(s):  
Organic Matter ◽  
Carbonate Rocks ◽  
Strength Properties ◽  
Low Density ◽  
Lower Strength ◽  
Reduction Processes ◽  
Local Areas ◽  
Oil Shales ◽  
Mosaic Distribution

Baltic oil shales — kukersites were studied as an example of rocks with rock-forming organic matter (OM). The volumetric significance of their OM is shown (due to the low density) in the volume and thickness of the shale layers. A higher OM content is responsible for a lower strength of the shales relative to the carbonate rocks of the deposit. The variable OM contents and other heterogeneities of the shale layers (structure, nodules, etc.) are factors of the mosaic distribution of areas with different density–strength properties and, as a result, of uneven reduction of layers and their deformation in the case of OM loss (full or partial). It is concluded that the intercalation of kukersite and limestone layers leads to density and strength anisotropy of the shale deposit. Episodic loss of OM and carbonates by the shales is considered for the local areas of the deposit: here, kukersites contain only a terrigenous component with clasts of limestones, shales, and epigenetic sulfides. The loss of OM is explained by sulfate-reduction processes in the underground hydrosphere.

scholarly journals INFLUENCE OF TECTONIC DISTURBANCES OF COAL LAYER ON HIS GAS DYNAMIC STATE

2021 ◽  
Vol 26 (1(38)) ◽  
pp. 192-204
Author(s):  
V. V. Zberovskyi ◽  
P. S. Pashenko ◽  
A. V. Pazynich ◽  
S. V. Stefanko
Keyword(s):  
Coal Seam ◽  
Strength Properties ◽  
Dynamic State ◽  
Gas Dynamic ◽  
Disturbed Zone ◽  
Tectonic Disturbances ◽  
Sudden Release ◽  
High Degree ◽  
Outburst Hazard

Problem Statement and Purpose. At one of the coal mines of the Donetsk basin, there was a sudden release of coal and gas. The peculiarity of this case is that the accident happened in the place of the alleged development of a geological disturbance, but without any visible signs of this. Inspection of the ejection site and adjacent horizons made it possible to conclude that the emergency site is located in the place of the plicative disturbance development. Thus, it is necessary to study in more detail the influence of disturbed zones hidden nature on the gas-dynamic state of the reservoir, as well as to develop and implement methods for determining such zones. Data & Methods. To achieve this goal, a new method was tested, based on the property of structureless substances to form crystal-like units. This phenomenon has been studied for decades; therefore, such new formations have long been given the name quasicrystals. It was noted that the increase in the concentration of such forms is associated with the presence of geological disturbances. Consequently, the increase in quasicrystals in the rock is an indicator of its disturbance due to the influence of tectonic pressure. Thus, in order to test the technique and reveal the hidden geological disturbance of the coal seam, coal samples were taken, microstructural features were studied, and the strength of the coal seam was measured at 56 points. Result. As a result the values of the concentration of quasicrystals, data on the strength of the formation were obtained, a schematic map of the development of the disturbance in this area was built, its contours were determined, the center of the disturbed zone was identified and the role of such disturbances in the outburst hazard of the formation was substantiated. It has been established that geological disturbances, even of plicative nature, have a high degree of fracturing. Such pores and cracks in coal reduce the strength properties and are able to concentrate sufficient volumes of gas for manifestation of GDP.

scholarly journals Role of Nb in 13Cr super-martensitic stainless steel

2013 ◽  
Vol 66 (2) ◽  
pp. 179-185 ◽  
Author(s):  
Xiaoping Ma ◽  
Cheng Zhou ◽  
Lijun Wang ◽  
Chunming Liu ◽  
Sundaresa Subramanian ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Martensitic Stainless Steel ◽  
Volume Fraction ◽  
Steel Sample ◽  
Strength Properties ◽  
Stainless Steel Sample ◽  
Precipitate Morphology ◽  
Super Martensitic Stainless Steel ◽  
Microalloying Elements

The effect of Nb microalloying on structure and physical properties of quenched and tempered 13%Cr martensitic stainless steel was investigated. Excellent strength and adequate toughness properties were obtained by 0.10 wt% Nb addition to low interstitial (N 0.01wt%, C < 0.02wt%) steel. The effect of Nb in 13%Cr steels with high N content was also studied in a commercial martensitic stainless steel sample containing higher levels of N and also alloyed with V. The microstructure, precipitate morphology and dispersion and volume fraction of reverse austenite were characterized. The strength properties obtained in the steel with 0.10%Nb are significantly higher than those of the V-containing steel. The study shows that whereas amount, size and dispersion of precipitates of microalloying elements contribute to enhanced strength, the optimum volume fraction of reverse austenite formed contributes to enhanced ductility and toughness properties. More importantly, high Nb additions to low N -13%Cr-1%Mo steel are found to improve significantly resistance against pitting corrosion significantly.

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