Methods to increase the reactivity of dissolving pulp in the viscose rayon production process: a review

Li, Hailong; Legere, Sarah; He, Zhibin; Zhang, Hongjie; Li, Jianguo; Yang, Bo; Zhang, Shaokai; Zhang, Lili; Zheng, Linqiang; Ni, Yonghao

doi:10.1007/s10570-018-1840-1

Cited by 53 publications

(28 citation statements)

References 110 publications

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“…Viscosity and analysis of molecular weight distribution indicate how much the cellulosic polymer chains in fibres have shortened during the enzymatic fibre treatments. Lower degree of polymerisation of cellulose is correlated with easier dissolution (Li et al 2018a).…”

Section: Viscosity and Molecular Weight Distributionsmentioning

confidence: 96%

“…Reference treatment was carried out without enzyme kinetics of individual fibres. Typically, the Fock test is used to measure fibre reactivity (Li et al 2018a). However, the Fock assay is linked to fibre dissolution in the viscose process which goes via cellulose derivatisation.…”

Section: Solubility Of Fibres In Cupriethylenediamine (Ced)mentioning

confidence: 99%

“…Good fibre reactivity, meaning good cellulose accessibility to dissolving and derivatizing chemicals is a prerequisite for environmentally benign processes that avoid excess use of chemicals (Li et al 2018a). Mechanical (Zhou et al 2018), chemical (Wang et al 2018) and enzymatic (Rahkamo et al 1998) pulp pretreatments and their combinations (Grönqvist et al 2015) have shown to improve fibre reactivity and cellulose accessibility.…”

Section: Introductionmentioning

confidence: 99%

“…Mechanical (Zhou et al 2018), chemical (Wang et al 2018) and enzymatic (Rahkamo et al 1998) pulp pretreatments and their combinations (Grönqvist et al 2015) have shown to improve fibre reactivity and cellulose accessibility. Fibre reactivity is affected by factors at several structural levels: at fibre, at microfibril and at molecular level (Li et al 2018a). At molecular level cellulose crystallinity and cellulose allomorphs, degree of polymerisation and the presence of other cell wall polymers have been associated with fibre reactivity.…”

Section: Introductionmentioning

confidence: 99%

“…At molecular level cellulose crystallinity and cellulose allomorphs, degree of polymerisation and the presence of other cell wall polymers have been associated with fibre reactivity. At microfibril and cell wall structural level the microfibril angels and orientations as well as porosity are thought to have an effect on reactivity (Li et al 2018a).…”

Section: Introductionmentioning

confidence: 99%

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Effect of cellulase family and structure on modification of wood fibres at high consistency

et al. 2019

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Enzymatic modification of bleached softwood kraft fibres for improved fibre reactivity was studied at high (20% w/w) and low (1% w/w) dry matter content. The role of enzyme family and structure in fibre modification was assessed using endoglucanases from three structurally different glycoside hydrolase (GH) families (5, 7 and 45) with and without a carbohydrate binding module (CBM). Based on the amount of dissolved sugars, enzyme action at high consistency was about sixfold higher compared to a fibre treatment at low consistency. The GH45 endoglucanase was found to be most specific in acting on pulp cellulose whereas the family 5 and 7 endoglucanases had activity also on pulp hemicelluloses. The GH45 endoglucanase was found to be most efficient in reducing molecular weight and viscosity of the pulp. In addition, treatment with the GH45 endoglucanase resulted in the highest micropore volume in fibres and thus an increase in cellulose accessibility. The increased accessibility could be seen as decreased dissolution time in cupriethylenediamine using recently developed analytical techniques: viscometric analysis and microscopic video analysis. At high consistency, CBM was not promoting enzyme action, although CBMs are known to be beneficial at low dry matter conditions.

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Section: Viscosity and Molecular Weight Distributionsmentioning

confidence: 96%

Section: Solubility Of Fibres In Cupriethylenediamine (Ced)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of cellulase family and structure on modification of wood fibres at high consistency

et al. 2019

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Influence of wood pulp quality on the structure of carboxymethyl cellulose

Fechter

Heinze

2019

J of Applied Polymer Sci

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The quality of carboxymethyl cellulose (CMC) prepared from different wood-derived market pulps is examined. The pulps represent kraft and sulfite qualities with different levels of hemicellulose (1.5-22.8 wt %), intrinsic viscosity (391-780 mL g −1 ), and content of extractives (0.04-0.13 wt %). The pulps are carboxymethylated in aqueous medium at three different levels of sodium hydroxide concentration, resulting in three levels of degree of substitution (DS), 0.3, 0.7-0.8, and 1.3-1.4 (according to nuclear magnetic resonance spectroscopy and high-performance liquid chromatography). CMC with DS 0.7-0.8 is found to be near the limit for water solubility and the resulting ranking for that solubility is shown to be correlated to DS. The DS is found to be impaired by a high content of impurities and high degree of Cellulose II in the pulp. The sulfite pulps yield CMC with the best solubility in water. A high level of extractives does not interfere with reactivity. Moreover, it is found that impurities, such as lignin and xylan, inhibit thickening behavior even at high DS, and that the ratio of substitution on Position 3 is a measure of the xylan content, which suggests that this position in xylan has extremely high reactivity.

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Optimizing the separation of xylose/xylan from eucalyptus woodchips in the autohydrolysis process

Ni,

Liang,

Gong

et al. 2023

Can J Chem Eng

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Effective separation of various components in biomass is critical for biorefinery. Autohydrolysis is a commercialized unit operation to remove hemicelluloses, such as xylan, in producing high‐quality cellulose (the so‐called dissolving pulp) in the pre‐hydrolysis kraft process. In the present study, the autohydrolysis of eucalyptus woodchips was investigated for the purpose of producing dissolving pulps, with a focus on the production of cellulose acetate grade dissolving pulp. First, the effects of liquid‐to‐solid ratio, maximum temperature, and time on hemicelluloses removal were comprehensively studied, and the total xylose saccharides concentration and total xylose saccharides yield were determined as a function of the P factor and log(Ro). The three‐variable Box–Behnken design of the response surface methodology was followed to optimize the autohydrolysis conditions, aiming to achieving the maximum removal of xylan. The as‐obtained optimal conditions were: liquid‐to‐solid ratio of 5.5 mL · g−1, maximum temperature of 165°C, and time of 120 min, with its P factor of 867 h and log(Ro) of 4.03. Under these conditions, the total xylose saccharides concentration was 16.43 g · L−1. Furthermore, the autohydrolysis yield was investigated. The results showed that the purity of as‐prepared cellulose substrate as a result of autohydrolysis at a P factor of 867 h (log(Ro) of 4.03) can meet the stringent requirement of cellulose acetate grade dissolving pulp. Furthermore, the pre‐hydrolysis liquor compositions were compared between the typical autohydrolysis conditions for rayon grade dissolving pulp (a P factor of 690 h and log(Ro) of 3.91) and the optimal conditions (a P factor of 867 h and log(Ro) of 4.03).

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Methods to increase the reactivity of dissolving pulp in the viscose rayon production process: a review

Cited by 53 publications

References 110 publications

Effect of cellulase family and structure on modification of wood fibres at high consistency

Effect of cellulase family and structure on modification of wood fibres at high consistency

Influence of wood pulp quality on the structure of carboxymethyl cellulose

Optimizing the separation of xylose/xylan from eucalyptus woodchips in the autohydrolysis process

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