Paper chemistry

Myllytie, Petri; Holappa, Susanna; Paltakari, Jouni; Laine, Janne

doi:10.3183/npprj-2009-24-02-p125-134

Cited by 27 publications

(36 citation statements)

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“…Different researchers got strength improvements [ 30 % at dryness between 30 and 55 % (Hamzeh et al 2013;Klein 2007;Laleg andPikulik 1992, 1993b;Myllytie 2009;Pikulik 1997;Salminen 2010). The structural similarity with the 1,4-glycosidic bonds are responsible for the adsorption capacity of Chitosan onto Cellulose (Klein 2007).…”

Section: Chemical Additivesmentioning

confidence: 99%

“…As a rule 0.2 mm is the size that is considered as fines in optical fiber analyzers. Several scientist, amongst others, worked on the topic of using or generating fibrils and fines to enhance the IWWS of paper (Brecht and Erfurt 1959b;Corson and Lobben 1980;Lindqvist 2013;Myllytie et al 2009;Pye et al 1965;Retulainen and Salminen 2009;Salminen 2010;Washburn and Buchanan 1964). Fibrils and fibrillar fines are supposed to increase the IWWS by better conformability that leads to improved frictional connection.…”

Section: Fibrils and Finesmentioning

confidence: 99%

“…It is concluded that the internal and external fibrillation are critical for the residual tension. The movement of the fibrils and fines during sheet forming is determined by the amount of water in the proximity of the fiber and by the elastic modulus that is in the range of 2-15 MPa for fibers (Myllytie 2009;Nilsson et al 2001;Scallan and Tigerström 1992). The SEM image performed by the authors in Fig.…”

Section: Fibrils and Finesmentioning

confidence: 99%

“…Even for wet web it improves the strength in a range of 20-25 % at 50 % dryness (Klein 2007;Myllytie 2009). This might be explained with the more uniform paper by reduced flocculation tendency that results in stronger wet webs (Linhart et al 1987;Nazhad et al 2000).…”

Section: Chemical Additivesmentioning

confidence: 99%

“…In additional papers, the bonds in wet sheets were explained based on a gel-like surface of the fiber (de Oliveira et al 2008;Lindqvist et al 2013;McKenzie 1984;Myllytie 2009). …”

Section: Fiber Water Gel On the Fiber Surfacementioning

confidence: 99%

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Initial wet web strength of paper

Belle

Odermatt

2016

Cellulose

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Despite much research into and development within the complex area of the initial wet web strength of paper, no complete model has yet been developed to describe this property. This type of paper strength is the most important property to ensure an effective paper machine run. Furthermore, the process of strength development in the sheet forming and pressing portion of the process is the basis of the final paper strength. Recent investigations have focused on the surface interactions of fibers on the molecular level. There have also been several innovative findings about fiber swelling and the impact of swelling on the mechanical characteristics of fibers in wet conditions. Overall, progress obtained using new methodologies enables a deeper understanding of the mechanism of strength development. This review discusses these important areas by examining the literature and the authors' own work to obtain a better understanding of the strength development in wet paper webs. This paper highlights that the fiber morphology and the dryness of the wet web have the greatest impact on the strength of the wet web. As fiber sources and machinery are fixed, the fiber water gel is one of the easiest factors to adjust via the process water quality and the use of chemical additives.

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Section: Chemical Additivesmentioning

confidence: 99%

Section: Fibrils and Finesmentioning

confidence: 99%

Section: Fibrils and Finesmentioning

confidence: 99%

Section: Chemical Additivesmentioning

confidence: 99%

“…In additional papers, the bonds in wet sheets were explained based on a gel-like surface of the fiber (de Oliveira et al 2008;Lindqvist et al 2013;McKenzie 1984;Myllytie 2009). …”

Section: Fiber Water Gel On the Fiber Surfacementioning

confidence: 99%

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Initial wet web strength of paper

Belle

Odermatt

2016

Cellulose

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Rheological Aspects of Cellulose Nanomaterials: Governing Factors and Emerging Applications

et al. 2021

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of nanomaterials from green, low-cost, abundant, renewable, and biodegradable natural resources. One such attractive bioresource is cellulose, the most abundant biopolymer on earth, which is widely present in various forms of renewable biomass, such as trees, plants, tunicates, and bacteria.Structurally, cellulose is a linear, high molecular weight polysaccharide with repeating glucose units linked by 1-4 glycosidic bonds. Owing to the presence of hydroxyl groups, those linear chains of glucose units link together through van der Waals forces and intermolecular hydrogen bonding to form elementary fibrils, which are further packed into larger aggregates known as microfibrils. [3] Cellulose fibrils consist of disordered (amorphous) regions and highly ordered (crystalline) regions. In the crystalline regions, cellulose chains are closely packed together in highly ordered fashion (parallel to the direction of fibril length), dictated by the intricate intraand intermolecular hydrogen bonding; whereas in the amorphous regions, cellulose chain stacking is less ordered and not as closely packed. Therefore, the amorphous regions are more vulnerable to both physical disintegration and chemical hydrolysis in comparison with crystalline regions. When cellulose is prepared in nano-scale fibrillar or crystalline forms, it is broadly referred to as cellulose nanomaterials (CNMs).The isolation, characterization, modification, and application of CNMs are currently receiving much attention. Understanding Cellulose nanomaterials (CNMs), mainly including nanofibrillated cellulose (NFC) and cellulose nanocrystals (CNCs), have attained enormous interest due to their sustainability, biodegradability, biocompatibility, nanoscale dimensions, large surface area, facile modification of surface chemistry, as well as unique optical, mechanical, and rheological performance. One of the most fascinating properties of CNMs is their aqueous suspension rheology, i.e., CNMs helping create viscous suspensions with the formation of percolation networks and chemical interactions (e.g., van der Waals forces, hydrogen bonding, electrostatic attraction/repulsion, and hydrophobic attraction). Under continuous shearing, CNMs in an aqueous suspension can align along the flow direction, producing shear-thinning behavior. At rest, CNM suspensions regain some of their initial structure immediately, allowing rapid recovery of rheological properties. These unique flow features enable CNMs to serve as rheological modifiers in a wide range of fluid-based applications. Herein, the dependence of the rheology of CNM suspensions on test protocols, CNM inherent properties, suspension environments, and postprocessing is systematically described. A critical overview of the recent progress on fluid applications of CNMs as rheology modifiers in some emerging industrial sectors is presented as well. Future perspectives in the field are outlined to guide further research and development in using CNMs as the next generation rheological modifiers.

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Biocatalytic Yarn for Peroxide Decomposition with Controlled Liquid Transport

Yuan

Zhang

Bilheux

et al. 2021

Adv Materials Inter

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A robust biocatalytic yarn with controllable liquid transport properties is created by coating thin layers of chitosan containing catalase onto a cellulosic yarn. The resulting material integrates enzyme catalytic functionality with protective coating properties of chitosan and structural functionality of the textile. Mild immobilization conditions and good affinity between the two polysaccharides minimize enzyme inactivation during the preparation steps and prevent enzyme from leaching during peroxide decomposition testing and washing, providing a novel and versatile enzyme immobilization strategy. The catalytic efficiency of enzymes in a reaction containing solid, liquid, and gas phases is facilitated when dissolved enzyme substrate is transported by liquid flowing through the coated textile structure. The flow‐through configuration decomposes at least two times more peroxide in a twenty‐times smaller reaction zone volume compared to a stirred tank configuration. Liquid transport through the yarn and liquid spatial distribution within the yarn are investigated by in situ neutron radiography and neutron computed tomography, revealing a constrained wicking mechanism that benefits biocatalytic yarn performance. This new class of sustainable and flexible biocatalytic textile matrices has beneficial multifunctional properties, not previously described, that are applicable for numerous small‐ and large‐scale applications including controlled flow reactors and reactive filtration.

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Paper chemistry

Cited by 27 publications

References 0 publications

Initial wet web strength of paper

Initial wet web strength of paper

Rheological Aspects of Cellulose Nanomaterials: Governing Factors and Emerging Applications

Biocatalytic Yarn for Peroxide Decomposition with Controlled Liquid Transport

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