scholarly journals H2O2 bleaching of brown pulp with adsorbed xylan and its modifying effects on the mechanical properties of paper

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 6814-6830
Author(s):  
Xue Zhang ◽  
Lizi Li ◽  
Junfei Tian ◽  
Nanhua Li ◽  
Leigang Zuo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Peroxide ◽  
Optical Properties ◽  
Kraft Pulp ◽  
Current Trend ◽  
Paper Properties ◽  
Effective Utilization ◽  
Bleaching Process ◽  
Hardwood Species ◽  
Initial Ph

Xylan is the primary hemicellulose in most hardwood species, especially in birch. Research has highlighted the exploitation of xylans as a strength-enhancing additive to paper due to the current trend for the effective utilization of biomass. In this paper, a new pulping process was proposed, which involved the extraction of xylan prior to pulping, followed by the re-adsorption of the pulp after the final stage in the digester, followed by a suitable bleaching process. The aim of this work was to bleach hardwood kraft pulp (brown pulp) with adsorbed birch xylan via hydrogen peroxide and study the effect of the bleaching parameters on the paper properties. The results showed that the optical properties of paper decreased; however, the mechanical properties increased after the brown pulp adsorbed birch xylan. During the bleaching process, better mechanical properties were obtained with shorter bleaching times and lower bleaching temperatures, initial pHs, and MgSO4 dosages. However, the optical properties were improved as the bleaching time, temperature, initial pH, and MgSO4 dosage were increased. The adsorption of birch xylan could effectively modify the mechanical properties of paper made from brown pulp under various phases.

scholarly journals Hydrogen peroxide bleaching of hardwood kraft pulp with adsorbed birch xylan and its effect on paper properties

BioResources ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. 721-736
Author(s):  
Lizi Li ◽  
Sanghoon Lee ◽  
Hak Lae Lee ◽  
Hye Jung Youn
Keyword(s):  
Hydrogen Peroxide ◽  
Optical Properties ◽  
Kraft Pulp ◽  
Strength Properties ◽  
Pulp Fibers ◽  
Paper Properties ◽  
Peroxide Bleaching ◽  
Initial Ph ◽  
The Relationship ◽  
Temperature Time

The adsorption of xylan on pulp fibers improves the strength properties of paper. However, the optical properties are decreased significantly. The objective of our research was to bleach hardwood kraft pulp with adsorbed birch xylan by hydrogen peroxide and study the effect of bleaching parameters on paper properties. The bleaching parameters studied included bleaching temperature, time, initial pH as well as MgSO4 dosage. The optical properties (whiteness, brightness, opacity) and physical properties (tensile index, tearing index, bulk) of handsheets made from the pulp bleached with different process variables were measured. The results showed that better optical properties were obtained with higher bleaching temperature, longer bleaching time, and more MgSO4 dosage. Bleaching from an initial pH of 11 provided the highest brightness value. On the other hand, strength properties were improved with decreasing of the bleaching temperature, and increasing the initial pH and MgSO4 dosage. The relationship between strength properties and bleaching time varied depending on bleaching temperature. According to the results, both good mechanical properties and optical properties could be achieved when the operating parameters were controlled properly. Therefore hydrogen peroxide bleaching was proved to be a suitable method for bleaching hardwood kraft pulp with adsorption of birch xylan.

scholarly journals Bleaching Process Investigation of Tunisian Dromedary Hair

ISRN Textiles ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
T. Harizi ◽  
S. Dhouib ◽  
S. Msahli ◽  
F. Sakli
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Peroxide ◽  
Adverse Effects ◽  
Oxalic Acid ◽  
Review Of The Literature ◽  
Bleaching Process ◽  
Bleaching Efficiency

Successful bleaching of pigmented fibres was, generally, evaluated by a maximum whiteness, a minimum yellowness, and less damage to the bleached fibers. A review of the literature reveals that many studies on pigmented fibre bleaching are concerned with improving the whiteness and mechanical properties of bleached fibres. In this study, we investigate the effects of the hydrogen peroxide concentration, bleaching time, and clarification bath on the bleaching efficiency of Tunisian dromedary hair. It was showed that 30 min bleaching time gives better result in term of whiteness. However, an increased bleaching time gives an excessive damage to the bleached fibers. Further, the damage incurred by the dromedary hair was more important than that for wool, as is shown by the tenacity results. We found that oxalic acid, which is used for rinsing dromedary hair (after bleaching), provides improved results in term of whiteness obtained with bleaching. Certainly, oxalic acid made it possible to remove the maximum of iron remaining on fibre after bleaching. Bleaching methods demonstrate the excessive damage incurred by the fibre when using hydrogen peroxide particularly with raise concentration. This damage leads to adverse effects on the tenacity fibre.

New evidence for the role of the borohydride pretreatment on the hydrogen peroxide bleaching of kraft pulp

RSC Advances ◽  
2015 ◽  
Vol 5 (119) ◽  
pp. 98067-98074 ◽  
Author(s):  
Jing Li ◽  
Huichao Hu ◽  
Yanting Song ◽  
Xin-Sheng Chai
Keyword(s):  
Hydrogen Peroxide ◽  
Kraft Pulp ◽  
Carbonyl Groups ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Chemical Pulps ◽  
New Evidence ◽  
Lignin Structure

New evidences for the role of borohydride pretreatment in hydrogen peroxide bleaching process of eucalyptus chemical pulps were provided, i.e., suppressing the catalysis effect of Fe(iii), decreasing carbonyl groups, and constituent lignin structure.

scholarly journals Effect of xylanase pretreatment on the kraft pulping of poplar

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 979-986
Author(s):  
Mehmet Akgül ◽  
Mehmet Onurhan Gücüş ◽  
Birol Üner ◽  
Celil Atik
Keyword(s):  
Mechanical Properties ◽  
Optical Properties ◽  
Kraft Pulp ◽  
Lignin Content ◽  
Kraft Pulping ◽  
Wood Chips ◽  
Populus X Euramericana ◽  
Cooking Conditions

This study aimed to determine the influence of prehydrolysis of wood chips on the kraft pulping of Populus x euramericana. Optimum cooking conditions were determined by evaluating different alkali concentrations and cooking periods. Xylanase was used to hydrolyze chips before cooking. Prehydrolysis process increased the yield and viscosity of pulp. Consequently, the mechanical properties of paper changed remarkably. In contrast, the optical properties of the unbleached kraft pulp declined due to lignin content.

scholarly journals DFT Study of Electronic Structure and Optical Properties of Kaolinite, Muscovite, and Montmorillonite

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 618
Author(s):  
Layla Shafei ◽  
Puja Adhikari ◽  
Wai-Yim Ching
Keyword(s):  
Mechanical Properties ◽  
Optical Properties ◽  
Electronic Structure ◽  
Hydrogen Bonds ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Bond Order ◽  
Deep Understanding ◽  
Pharmaceutical Applications ◽  
Structure Properties

Clay mineral materials have attracted attention due to their many properties and applications. The applications of clay minerals are closely linked to their structure and composition. In this paper, we studied the electronic structure properties of kaolinite, muscovite, and montmorillonite crystals, which are classified as clay minerals, by using DFT-based ab initio packages VASP and the OLCAO. The aim of this work is to have a deep understanding of clay mineral materials, including electronic structure, bond strength, mechanical properties, and optical properties. It is worth mentioning that understanding these properties may help continually result in new and innovative clay products in several applications, such as in pharmaceutical applications using kaolinite for their potential in cancer treatment, muscovite used as insulators in electrical appliances, and engineering applications that use montmorillonite as a sealant. In addition, our results show that the role played by hydrogen bonds in O-H bonds has an impact on the hydration in these crystals. Based on calculated total bond order density, it is concluded that kaolinite is slightly more cohesive than montmorillonite, which is consistent with the calculated mechanical properties.

scholarly journals A new expansion material used for roof-contacted filling based on smelting slag

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hua Na ◽  
Guocheng Lv ◽  
Lijuan Wang ◽  
Libing Liao ◽  
Dan Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Peroxide ◽  
Compressive Strength ◽  
Sodium Silicate ◽  
Utilization Rate ◽  
Ammonium Bromide ◽  
Foaming Agent ◽  
Copper Nickel ◽  
Smelting Slag ◽  
Nickel Smelting

AbstractThe improper handling of smelting slag will seriously pollute the environment, and the unfilled roof of the goaf of the mine will threaten the safety of the mine. Expansion materials have attracted more and more attention because of their excellent properties. In this paper, copper-nickel smelting slag that has some active ingredients of gelling is used instead of traditional aggregate and some part of cement in order to reduce its pollution to the environment and its costs. For safety reasons, hydrogen peroxide was chosen as the foaming agent. Sodium silicate and hexadecyl trimethyl ammonium bromide (CTAB) are used as additives. Our results showed that after 28 days of curing, the material has better mechanical properties and the early compressive strength of the material was enhanced by sodium silicate. The efficiency of foaming was improved by CTAB. It also proves that copper–nickel smelting slag can be used in expansion material. At the same time, the utilization rate of the copper–nickel smelting slag of this formula can reach 70%, reduce its pollution to the environment.

scholarly journals RECENT APPLICATIONS AND INNOVATIONS OF CELLULOSE BASED MATERIALS: A CRITICAL REVIEW

2021 ◽  
Vol 55 (1-2) ◽  
pp. 1-12
Author(s):  
TSHWAFO ELIAS MOTAUNG
Keyword(s):  
Mechanical Properties ◽  
Optical Properties ◽  
Thermal Degradation ◽  
Polymer Composites ◽  
Critical Review ◽  
Industrial Applications ◽  
Knowledge Gaps ◽  
Cellulosic Materials ◽  
Synthetic Fibers ◽  
Industrial Needs

"This review presents recent research on cellulosic materials and its latest uses, as well as scientific possibilities for more applications. Cellulose continues to display its advantages over synthetic fibers and its potential to replace fossilbased materials, which are known to harm ecosystems. Common attractive applications of cellulose include packaging, healthcare materials, electronics and printing. Most applications seem to rotate around the equilibrium of hydrophilicity, its mechanical properties and optical properties. Details on industrial applications, knowledge gaps and green innovations in cellulose conductivity, as well as limitations of its thermal degradation, are thoroughly covered. Most innovations are motivated by industrial needs, because renewability and inexpensiveness are the latest additional values to most industries. All common and innovative pretreatments are well summarized in this review. Furthermore, the paper provides interesting details on cellulose polymer composites, their applications and some recommendations for further research."

scholarly journals Synthesis of HTPB using a semi-batch method

2020 ◽  
pp. 192-202
Author(s):  
Michał Chmielarek ◽  
Wincenty Skupiński ◽  
Zdzisław Wieczorek
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Peroxide ◽  
Synthesis Method ◽  
Batch Method ◽  
Synthesis Conditions ◽  
Rocket Propellants ◽  
Wide Range ◽  
Military Applications ◽  
Solid Rocket ◽  
Solid Rocket Propellants

Hydroxyl-terminated polybutadiene is widely used in industry for both civil and military applications. In munitions, HTPB is mostly used as a binder for heterogenic rocket propellants and as a component of plastic bonded explosives, as well as a phlegmatizer in explosives sensitive to friction and impact. The wide range of HTPB applications results from the good mechanical properties of HTPB-based polyurethanes, in particular at temperatures down to –40 °C. A synthesis method for HTPB, different from the commonly used semi-batch and continuous methods, is presented. The effect of parameters including reaction temperature, 1,3-butadiene pressure and hydrogen peroxide concentration on the properties of the obtained polymer is determined. The synthesis conditions enabling new HTPB species to be obtained, which meet the requirements for binders used in solid rocket propellants, are specified.

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