Modification of High Lignin Content Kraft Pulps with Laccase to Improve Paper Strength Properties. 1. Laccase Treatment in the Presence of Gallic Acid

2008 ◽  
Vol 20 (1) ◽  
pp. 255-261 ◽  
Author(s):  
Richard P. Chandra ◽  
Lauri K. Lehtonen ◽  
Arthur J. Ragauskas
Keyword(s):  
Gallic Acid ◽  
Lignin Content ◽  
Strength Properties ◽  
Kraft Pulps ◽  
Paper Strength ◽  
High Lignin Content

scholarly journals Chemical characteristics and Kraft pulping of tension wood from Eucalyptus globulus labill

2012 ◽  
Vol 36 (6) ◽  
pp. 1163-1172 ◽  
Author(s):  
María Graciela Aguayo ◽  
Regis Teixeira Mendonça ◽  
Paulina Martínez ◽  
Jaime Rodríguez ◽  
Miguel Pereira
Keyword(s):  
Eucalyptus Globulus ◽  
Lignin Content ◽  
Strength Properties ◽  
Kraft Pulping ◽  
Pulp Yield ◽  
Chemical Characteristics ◽  
Kraft Pulps ◽  
Opposite Wood ◽  
Alkali Consumption ◽  
Pulp Strength

Tension (TW) and opposite wood (OW) of Eucalyptus globulus trees were analyzed for its chemical characteristics and Kraft pulp production. Lignin content was 16% lower and contained 32% more syringyl units in TW than in OW. The increase in syringyl units favoured the formation of β-O-4 bonds that was also higher in TW than in OW (84% vs. 64%, respectively). The effect of these wood features was evaluated in the production of Kraft pulps from both types of wood. At kappa number 16, Kraft pulps obtained from TW demanded less active alkali in delignification and presented slightly higher or similar pulp yield than pulps made with OW. Fiber length, coarseness and intrinsic viscosity were also higher in tension than in opposite pulps. When pulps where refined to 30°SR, TW pulps needed 18% more revolutions in the PFI mill to achieve the same beating degree than OW pulps. Strength properties (tensile, tear and burst indexes) were slightly higher or similar in tension as compared with opposite wood pulps. After an OD0(EO)D1 bleaching sequence, both pulps achieved up to 89% ISO brightness. Bleached pulps from TW presented higher viscosity and low amount of hexenuronic acids than pulps from OW. Results showed that TW presented high xylans and low lignin content that caused a decrease in alkali consumption, increase pulp strength properties and similar bleaching performance as compared with pulps from OW.

Selectivity of oxygen delignification for southern softwood kraft pulps with high lignin content

TAPPI Journal ◽  
2011 ◽  
Vol 10 (8) ◽  
pp. 29-39 ◽  
Author(s):  
LI TAO ◽  
JOSEPH M. GENCO ◽  
BARBARA J.W. COLE ◽  
RAYMOND C. FORT
Keyword(s):  
Hydroxyl Radicals ◽  
Lignin Content ◽  
Degree Of Polymerization ◽  
Kraft Pulping ◽  
Kraft Pulps ◽  
Oxygen Delignification ◽  
Kraft Process ◽  
Carbohydrate Degradation ◽  
Polymeric Chains ◽  
High Lignin Content

The selectivity of kraft pulping versus the oxygen delignification processes over the range of kappa nos. 25–90 was compared. Kraft pulping was found to be more selective than oxygen delignification for removing lignin from southern softwood kraft pulps. The greater selectivity is thought to be related to hydroxyl radicals that form in the oxygen delignification process that are not present in the kraft process. The hydroxyl radicals attack the carbohydrates and randomly cleave the polymeric chains, causing a significant decrease in the degree of carbohydrate polymerization and thus a loss of viscosity. Kraft pulping generates hydrosulfide ions that are highly selective and attack the lignin. Carbohydrate degradation occurs mainly from peeling reactions, which do not appreciably reduce the degree of polymerization of the cellulose and thus there is less viscosity loss. At low lignin content (i.e., low kappa number), the remaining lignin is likely bound covalently to the carbohydrate portion in both processes. Therefore, removal of the lignin results in significant degradation of the carbohydrates.

Improving paper wet strength via increased lignin content and hot-pressing temperature

TAPPI Journal ◽  
2020 ◽  
Vol 19 (10) ◽  
pp. 487-497
Author(s):  
TOVE JOELSSON ◽  
GUNILLA PETTERSSON ◽  
SVEN NORGREN ◽  
ANNA SVEDBERG ◽  
HANS HOGLUND ◽  
...  
Keyword(s):  
Hot Pressing ◽  
Lignin Content ◽  
Pilot Scale ◽  
Strength Properties ◽  
High Yield ◽  
Kraft Pulps ◽  
Pressing Temperature ◽  
Wet Strength ◽  
Tensile Index ◽  
Reference Samples

It is known that the strength properties of wood-based paper materials can be enhanced via hot-pressing techniques. Today, there is a desire not only for a change from fossil-based packaging materials to new sustainable bio-based materials, but also for more effective and eco-friendly solutions for improving the dry and wet strength of paper and board. Against this background, hot pressing of paper made from high yield pulp (HYP), rich in lignin, becomes highly interesting. This study investigated the influence of pressing temperature and native lignin content on the properties of paper produced by means of hot pressing. Kraft pulps of varied lignin content (kappa numbers: 25, 50, 80) were produced at pilot scale from the same batch by varying the cooking time. We then studied the effect of lignin content by evaluating the physical properties of Rapid Köthen sheets after hot pressing in the temperature range of 20°C–200°C with a constant nip pressure of 7 MPa. The pilot-scale cooked pulps were compared with reference samples of mill-produced northern bleached soft-wood kraft (NBSK) pulp and mill-produced chemithermomechanical pulp (CTMP). Generally, the results demonstrated that lignin content had a significant effect on both dry and wet tensile index. All of the pilot cooked pulps with increased lignin content had a higher tensile index than the reference NBSK pulp. To obtain high tensile index, both dry and wet, the pressing temperature should be set high, preferably at least 200°C; that is, well above the glass transition temperature (Tg) for lignin. Moreover, the lignin content should preferably also be high. All kraft pulps investigated in this study showed a linear relationship between wet strength and lignin content.

Characterisation of fines from unbleached kraft pulps and their impact on sheet properties

Holzforschung ◽  
2008 ◽  
Vol 62 (5) ◽  
Author(s):  
Marie Bäckström ◽  
Marie-Claude Kolar ◽  
Myat Htun
Keyword(s):  
Mechanical Properties ◽  
Capillary Forces ◽  
Strength Properties ◽  
Kraft Pulps ◽  
Paper Strength ◽  
Essential Component ◽  
Profound Influence ◽  
The Creation ◽  
Strength Improvement

Abstract Fines are an essential component in the papermaking process because they have a profound influence on the behaviour of the wet web and on the mechanical properties of the final sheet. Primary fines are present in the pulp prior to refining, and secondary fines are produced during refining. In the present investigation, two commercially manufactured unbleached pulps with kappa numbers of 45 and 90 were studied in terms of how they responded to refining with respect to the quality of fibre and fines. Primary and secondary fines were collected and characterised and their impact on sheet strength was evaluated by addition of known amounts to a refined and decrilled pulp. All the measured paper strength properties improved when primary and secondary fines were added. The strength improvement was generally somewhat higher in the second case. The effect was more pronounced at a higher level of addition. We attribute the main strength improvements associated with fines to improved consolidation by the creation of capillary forces between the surfaces.

The Impact of Lignin Content on Paper Physical Strength of CTMP

2011 ◽  
Vol 236-238 ◽  
pp. 1242-1245
Author(s):  
Ben Ping Lin ◽  
Bei Hai He ◽  
Guang Lei Zhao
Keyword(s):  
Lignin Content ◽  
Strength Properties ◽  
Paper Strength ◽  
Fiber Morphology ◽  
Burst Strength ◽  
Physical Strength ◽  
The Impact ◽  
Linear Correlations ◽  
Total Lignin ◽  
Total Lignin Content

The research reported here gives some new insights into the influence of lignin content on paper strength properties. The relative amount of total lignin in CTMP was varied by using multistage ClO2 bleaching method. Few differences were observed in fiber morphology charcteristics of CTMP during ClO2 treatments. Linear correlations greater than 99% were found between total lignin content and paper strength properties. The influences of lignin content on Scott bond and tensile strength were greater than that of tear and burst strength.

Biobleaching chemistry of laccase-mediator systems on high-lignin-content kraft pulps

2004 ◽  
Vol 82 (2) ◽  
pp. 344-352 ◽  
Author(s):  
Fadi S Chakar ◽  
Arthur J Ragauskas
Keyword(s):  
Kraft Pulp ◽  
Structural Changes ◽  
Lignin Content ◽  
Kraft Pulps ◽  
Carboxylic Acid Groups ◽  
Violuric Acid ◽  
Mediator Systems ◽  
Before And After ◽  
Softwood Kraft Pulp ◽  
High Lignin Content

A high-lignin-content softwood kraft pulp was reacted with laccase in the presence of 1-hydroxybenzotriazole (HBT), N-acetyl-N-phenylhydroxylamine (NHA), and violuric acid (VA). The biodelignification response with violuric acid was superior to both 1-hydroxybenzotriazole and N-acetyl-N-phenylhydroxylamine. NMR analysis of residual lignins isolated before and after the biobleaching treatments revealed that the latter material was highly oxidized and that the magnitude of structural changes was most pronounced with the laccase – violuric acid biobleaching system. An increase in the content of carboxylic acid groups and a decrease in methoxyl groups were noted with all three laccase-mediator systems. The oxidation biobleaching pathway is directed primarily towards noncondensed C5 phenolic lignin functional structures for all three laccase-mediated systems. The laccase – violuric acid system was also reactive towards C5-condensed phenolic lignin structures.Key words: laccase, mediator, lignin, pulp, biobleaching, phenolics.

A novel predictive method for filler coflocculation with cellulose microfibrils

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 653-664
Author(s):  
IGNACIO DE SAN PIO ◽  
KLAS G. JOHANSSON ◽  
PAUL KROCHAK
Keyword(s):  
Negative Impact ◽  
High Strength ◽  
Strength Properties ◽  
Cellulose Microfibrils ◽  
Paper Strength ◽  
Flow Loop ◽  
Cationic Starch ◽  
Reflectance Measurement ◽  
Drainage Rate ◽  
Complete Study

Different strategies aimed at reducing the negative impact of fillers on paper strength have been the objective of many studies during the past few decades. Some new strategies have even been patented or commercialized, yet a complete study on the behavior of the filler flocs and their effect on retention, drainage, and formation has not been found in literature. This type of research on fillers is often limited by difficulties in simulating high levels of shear at laboratory scale similar to those at mill scale. To address this challenge, a combination of techniques was used to compare preflocculation (i.e., filler is flocculated before addition to the pulp) with coflocculation strategies (i.e., filler is mixed with a binder and flocculated before addition to the pulp). The effect on filler and fiber flocs size was studied in a pilot flow loop using focal beam reflectance measurement (FBRM) and image analysis. Flocs obtained with cationic polyacrylamide (CPAM) and bentonite were shown to have similar shear resistance with both strategies, whereas cationic starch (CS) was clearly more advantageous when coflocculation strategy was used. The effect of flocculation strategy on drainage rate, STFI formation, ash retention, and standard strength properties was measured. Coflocculation of filler with CPAM plus bentonite or CS showed promising results and produced sheets with high strength but had a negative impact on wire dewatering, opening a door for further optimization.

Deep eutectic solvent delignification: Impact of initial lignin

BioResources ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 7301-7310
Author(s):  
Veronika Majová ◽  
Silvia Horanová ◽  
Andrea Škulcová ◽  
Jozef Šima ◽  
Michal Jablonský
Keyword(s):  
Lactic Acid ◽  
Oxalic Acid ◽  
Lignin Content ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Deep Eutectic Solvents ◽  
Kappa Number ◽  
Kraft Pulps ◽  
Oxygen Delignification ◽  
Detailed Understanding

This study aimed to resolve the issue of the lack of detailed understanding of the effect of initial lignin content in hardwood kraft pulps on pulp delignification by deep eutectic solvents. The authors used Kappa number of the concerned pulp, intrinsic viscosity, and selectivity and efficiency of delignification as the parameters of the effect. The pulp (50 g oven dry pulp) was treated with four different DESs systems based on choline chloride with lactic acid (1:9), oxalic acid (1:1), malic acid (1:1), and system alanine:lactic acid (1:9); the results were compared to those reached by oxygen delignification. The results showed that the pulp with a higher initial lignin content had a greater fraction of easily removed lignin fragments.

Characterisation of Drawing Papers for Borko Lazeski’s Cartoons (1951–56)

2018 ◽  
Vol 39 (3) ◽  
pp. 157-183
Author(s):  
Maja Kostadinovska
Keyword(s):  
Raman Spectroscopy ◽  
Chemical Nature ◽  
Lignin Content ◽  
Mural Painting ◽  
Micro Raman Spectroscopy ◽  
Different Types ◽  
Informed Treatment ◽  
Acidic Conditions ◽  
Spot Tests ◽  
High Lignin Content

Abstract This paper presents a study of the drawing papers from Borko Lazeski’s cartoons for a mural painting. The collection is comprised of more than 20 single pieces (170×500 cm) executed in charcoal, pencil, pastel, tempera and ink. The cartoons exhibit different types of damages, such as grease stains, moisture stains, cracks, flaking paint, areas of loss caused by insects and mould stains. The study included spot tests, ATR-FTIR and micro-Raman spectroscopy to characterise the artist’s papers. They were found to be a type of paper composed of partly bleached, neutral sulphite semi-chemical (NSSC) wood pulp originating from coniferous trees (softwood) with the occasional use of abaca fibres. The laboratory tests revealed slightly acidic conditions (pH=5.01–6.52), high lignin content (>5 %) and alum-rosin sizing. Infrared spectroscopy confirmed all findings of the spot tests. Micro-Raman spectroscopy showed the presence of gypsum in the papers. The study addresses conservation issues arising from the chemical nature of the paper support and highlights the need for an extended study in order to be able to make informed treatment choices.

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