Chemical modification of pulp fibers by TEMPO-mediated oxidation

Kitaoka, Takuya; Isogai, Akira; Onabe, Fumihiko

doi:10.3183/npprj-1999-14-04-p279-284

Cited by 101 publications

(87 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The intrinsic viscosity measurements showed that all the oxidized pulp samples had a low viscosimetric degree of polymerization (DP V ), in agreement with Kitaoka et al (1999), compared to the non-oxidized reference pulp (DP V 1250). The trends seen in the data for DP V are to be expected because a higher temperature and a higher dosage of sodium hypochlorite should result in more extensive degradation of the cellulose polymers.…”

Section: Pulp Propertiessupporting

confidence: 48%

“…Dang et al (2007) reported that a greater amount of negatively charged carboxylate groups, after TEMPO oxidation, enhanced the water retention value (WRV), thus indicating enhanced fibre swelling. In contrast to this, Kitaoka et al (1999) found that the WRV was almost unaffected, even though the amount of carboxylate groups was increased from 0.06 to 0.47 mmol/g. Under alkaline conditions, TEMPO oxidation has been tested at low and moderate temperatures up to room temperature level.…”

contrasting

confidence: 44%

“…An average intrinsic viscosity was obtained, based on three measurements. The viscosimetric average degree of polymerization was calculated from the intrinsic viscosity of the dissolved pulp solutions at 25 ˚C, using the method according to Dissolution in a CED solution has been reported to give further depolymerization of TEMPO-oxidized pulps (Kitaoka et al 1999;da Silva Perez et al 2003), e.g., a sample of TEMPO-oxidized pulp dissolved in a CED solution was reported to have a DP of about 250 instead of about 500 when the same pulp was dissolved in SO 2 -diethylaminedimethylsulfoxide. Thus, this method may overestimate the difference in the DP V between unoxidized pulps and oxidized pulps, but it can be used for a relative comparison.…”

Section: Analysesmentioning

confidence: 99%

“…Isogai and Kato (1998) studied the influence of TEMPO oxidation conditions and found that higher temperature and longer oxidation time resulted in a lower DP in the oxidized pulps. Kitaoka et al (1999) reported that the DP decreased rapidly when the pulp was subjected to TEMPO oxidation, but at a higher dosage of sodium hypochlorite charge, the DP leveled out at about 200. TEMPO oxidation can also be performed at near neutral conditions (Saito et al 2009), using a TEMPO/NaClO/NaClO 2 reaction system.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

High Temperature TEMPO Oxidation in a Heterogeneous Reaction System: An Investigation of Reaction Kinetics, Pulp Properties, and Disintegration Behavior

Brodin¹,

Theliander²

2013

BioResources

View full text Add to dashboard Cite

TEMPO oxidation was performed on never-dried bleached softwood kraft pulp fibres to study the influence of reaction temperature and the dosage of sodium hypochlorite in the oxidation treatment. It was found that oxidation at a high temperature shortened oxidation time, but it also resulted in more extensive degradation of the pulp. Harsh reaction conditions (high temperature and high dosage of sodium hypochlorite) enabled the rapid disintegration of pulp fibres with a low energy demand. The freeze-dried disintegrated pulp fibres had a high absorption capacity of saline liquid, 40 to 80 g/g, and retained 9 to 14 g saline liquid/g material in a standard centrifuge retention test. Four different models were investigated to describe the kinetics of TEMPO oxidation of pulp fibres. However, none of the models could adequately describe all the mechanisms involved in this reaction system. The results showed that the diffusion of hypochlorite ions was sufficiently fast compared to the chemical reactions. In contrast, the concentration of the catalytic compounds, NaBr and TEMPO, both had a strong influence on the reaction rate. Results show that the reactions have different phases, possibly with different rate-determining steps. It remains to be determined which reaction steps correspond to the different phases. Keywords INTRODUCTIONCellulose is currently only used in a few different products, mostly various paper products, but the demand for new cellulose-based products, e.g., viscose and various cellulose derivatives, is growing. Because cellulose is the most abundant biomaterial on earth, it can be expected that cellulose-based products will find many new applications in the future, e.g., as replacement products in applications that, today, are dominated by products produced from fossil-based resources.Cellulose extracted from wood using chemical pulping methods is an excellent starting material for developing new biomaterials. In many cases, however, it will be necessary to modify the cellulose properties to fulfill the needs of the new applications. There are many ways of modifying cellulose, and one of these is oxidizing the hydroxyl groups in the cellulose, thus forming new aldehyde and carboxylate groups. Primary hydroxyl groups can be oxidized selectively through so-called TEMPO oxidation, where a catalytic amount of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) mediates the oxidation of cellulose and is regenerated by a primary oxidant (Bragd et al. 2004). This PEER-REVIEWED ARTICLE bioresources.com Brodin and Theliander (2013). "TEMPO ox. kinetics," BioResources 8(4), 5925-5946. 5926 type of modification also causes a substantial decrease in the degree of polymerization (DP) (Saito and Isogai 2004), i.e., the molecular weight of the cellulose polymers decreases. Saito et al. (2006) found that TEMPO-oxidized pulp fibres could be disintegrated into microfibrillar cellulose (MFC) through treatment in a Waring blender. Furthermore, they reported that the disintegration of TEMPO-oxidized sulfite pulp was facilitat...

show abstract

Section: Pulp Propertiessupporting

confidence: 48%

contrasting

confidence: 44%

Section: Analysesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

High Temperature TEMPO Oxidation in a Heterogeneous Reaction System: An Investigation of Reaction Kinetics, Pulp Properties, and Disintegration Behavior

Brodin¹,

Theliander²

2013

BioResources

View full text Add to dashboard Cite

show abstract

“…Importantly, the presence of these reactive 45 hydroxyl groups allows cellulose to be modified and functionalized, by introducing new 46 functional groups to improve its nano-dispersibility or even confer it an added-value for specific 47 applications such as medical (scaffolding material), agricultural, cosmetic and pharmaceutical 48 and carboxyl functionalities are known to play a decisive role in the pulping process and hence in 51 the final paper properties. For example, sheets made from the partially oxidized fibers 52 experienced higher wet and dry tensile index, presumably due to an increased opportunity of 53 electrostatic interactions between anionic pulp and cationic polyamideamine-epichlorohydrin, 54 which was added as a wet-strength agent (Kitaoka, Isogai, & Onabe, 1999). 55…”

mentioning

confidence: 99%

Cellulose oxidation by Laccase-TEMPO treatments

Quintana

Roncero

Vidal

et al. 2017

Carbohydrate Polymers

View full text Add to dashboard Cite

17In this work, laccase-TEMPO (Lac-T) treatments were applied to bleached commercial 18 dissolving pulp in order to introduce carbonyl and carboxyl groups, which were found to 19 improve dry and wet strength-related properties. Also the solubility behavior towards xanthate 20 reactions was assessed. The effect of a refining step (R) before the oxidative treatment, the 21 absence or presence of oxygen pressure, TEMPO dose (2 or 8% oven dried pulp) and reaction 22 time (8 or 20h) were thoroughly examined. Treatments conducted in the presence of oxygen 23 pressure exhibited greater amount of functional groups. Introducing a pre-refining treatment 24 resulted in similar functional groups but higher wet strength was achieved. Specifically, a high 25 W/D strength ratio was observed, indicating that wet strength-related property was satisfactorily 26 developed. Besides the fact that all Lac-T treatments caused severe cellulose degradation, no 27 fiber strength loss was detected. In fact, all oxidized samples presented higher wet zero-span 28 tensile strength, mainly in R+ Lac-T (O 2 ) sample, which suggested the formation of hemiacetal 29 linkages between the new introduced aldehyde groups and available free hydroxyl groups 30 resulting from fibrillation. 31 32

show abstract

Selective Isolation Methods for Cellulose and Chitin Nanocrystals

Yang

Liu

et al. 2020

ChemPlusChem

View full text Add to dashboard Cite

This Minireview focuses on the selective isolation methods for the preparation of cellulose nanocrystals (CNCs) and chitin nanocrystals (ChNCs). Various selective preparation strategies with specific preparation conditions and reaction mechanisms are summarized. In particular, these selective reaction routes include controlled acid hydrolysis and selective oxidations at specific positions of cellulose or chitin fibers as well as particular reaction sites of the repeating monosaccharide building blocks of their main chains. These lead to selective cleavage of the ordered and non-ordered regions of cellulose and chitin and result in efficient production of CNCs and ChNCs. [ + ] These authors contributed equally to this work.

show abstract

Chemical modification of pulp fibers by TEMPO-mediated oxidation

Cited by 101 publications

References 0 publications

High Temperature TEMPO Oxidation in a Heterogeneous Reaction System: An Investigation of Reaction Kinetics, Pulp Properties, and Disintegration Behavior

High Temperature TEMPO Oxidation in a Heterogeneous Reaction System: An Investigation of Reaction Kinetics, Pulp Properties, and Disintegration Behavior

Cellulose oxidation by Laccase-TEMPO treatments

Selective Isolation Methods for Cellulose and Chitin Nanocrystals

Contact Info

Product

Resources

About