Process modifications to obtain a prehydrolysis kraft dissolving pulp with low limiting pulp viscosity

Brännvall, Elisabet; Walter, Karin

doi:10.1515/npprj-2019-0100

Cited by 3 publications

(2 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was similar to what has been reported in earlier work on regenerated cellulose fibers from the cold NaOH(aq) process [26,27]. Further information regarding the cellulose pulp and its preparation was given by Brännvall and Walter [28].…”

Section: Methodssupporting

confidence: 88%

Carbon Fibers from Wet-Spun Cellulose-Lignin Precursors Using the Cold Alkali Process

Bengtsson

Landmér

Norberg

et al. 2022

Fibers

Self Cite

View full text Add to dashboard Cite

In recent years, there has been extensive research into the development of cheaper and more sustainable carbon fiber (CF) precursors, and air-gap-spun cellulose-lignin precursors have gained considerable attention where ionic liquids have been used for the co-dissolution of cellulose and lignin. However, ionic liquids are expensive and difficult to recycle. In the present work, an aqueous solvent system, cold alkali, was used to prepare cellulose-lignin CF precursors by wet spinning solutions containing co-dissolved dissolving-grade kraft pulp and softwood kraft lignin. Precursors containing up to 30 wt% lignin were successfully spun using two different coagulation bath compositions, where one of them introduced a flame retardant into the precursor to increase the CF conversion yield. The precursors were converted to CFs via batchwise and continuous conversion. The precursor and conversion conditions had a significant effect on the conversion yield (12–44 wt%), the Young’s modulus (33–77 GPa), and the tensile strength (0.48–1.17 GPa), while the precursor morphology was preserved. Structural characterization of the precursors and CFs showed that a more oriented and crystalline precursor gave a more ordered CF structure with higher tensile properties. The continuous conversion trials highlighted the importance of tension control to increase the mechanical properties of the CFs.

show abstract

Section: Methodssupporting

confidence: 88%

Carbon Fibers from Wet-Spun Cellulose-Lignin Precursors Using the Cold Alkali Process

Bengtsson

Landmér

Norberg

et al. 2022

Fibers

Self Cite

View full text Add to dashboard Cite

show abstract

“…Oxygen bleaching is less selective than, for instance, chlorine dioxide as a delignification agent. A consequence of this lower selectivity is a greater tendency to decrease the DP of the cellulose (Pouyet et al 2013;Brännvall and Walter 2020). A few mills, mainly in the Nordic countries, have been running without any chlorine-containing bleaching agents.…”

Section: Bleaching Of Kraft Pulpsmentioning

confidence: 99%

Archival performance of paper as affected by chemical components: A Review

Hubbe

Maitland²,

Nanjiba

et al. 2023

BioRes

View full text Add to dashboard Cite

For about two millennia, paper has served as a main medium for preservation of people’s ideas, stories, contracts, and art. This article reviews what is known about the various components that make up paper from the perspective of their long-term stability under typical storage conditions. Literature evidence is considered relative to the susceptibility of different paper components to embrittlement, acid hydrolysis, microbiological attack, and discoloration, among others. The cellulose that makes up a majority of most paper items is demonstrably stable enough to persist for many hundreds of years on the shelves of archival collections, though it is susceptible to acid-catalyzed hydrolysis, which can be accelerated by byproducts of decomposition. Though less attention has been paid to the archival performance of various minor components of modern paper products, evidence suggests that at least some of them are subject to likely breakdown, embrittlement, or decay in the course of prolonged storage. Based on these considerations, one can envision different categories of paper that can be expected to meet different levels of storage stability: ancient recipes for handmade papermaking, e.g. washi and hanji, archival-grade paper products, ordinary modern alkaline paper products, and paper manufactured without concerns for its longevity.

show abstract

Convective Heat Transfer Coefficient of Insulation Paper–Oil Contact Surface of Transformer Vertical Oil Channel

Luo

Wan

et al. 2023

Coatings

View full text Add to dashboard Cite

Insulation paper is the primary inter-turn insulation material for transformer windings. However, insulation paper is a poor conductor of heat and seriously impacts the natural convective heat dissipation in the winding oil channels. In order to study the convective heat transfer performance of the transformer vertical oil channel, the heat transfer characteristics of the two-dimensional boundary layer of the insulation paper–oil contact surface were analysed, and a characteristic number equation with a roughness correction factor was established. Based on the similarity principle and modelling theory, an experimental apparatus was designed to determine the convective heat transfer coefficient of the insulation paper–oil contact surface. Coefficients were obtained for different qualitative temperatures and characteristic lengths. Parametric fitting of the experimental data was carried out to obtain the correction factors. The results show that the natural convective heat transfer coefficient h of the insulation paper–oil contact surface is positively and linearly related to qualitative temperature and inversely related to characteristic length. For temperatures of 312.9 K to 328.1 K and characteristic lengths of 3 cm, h ranges from 116.15 to 144.38 W/(m2· K). For temperatures of 319.0 K to 337.9 K and lengths of 6 cm, h ranges from 103.79 to 131.14 W/(m2· K). The correction factor of the characteristic equation coefficient is 1.067. The maximum deviation of h calculated with a coefficient of 0.63 and an exponent of 0.25 is 5.93%. The results are essential for modelling the transformer space thermal circuit and solving the hot-spot temperature problem.

show abstract

Process modifications to obtain a prehydrolysis kraft dissolving pulp with low limiting pulp viscosity

Cited by 3 publications

References 22 publications

Carbon Fibers from Wet-Spun Cellulose-Lignin Precursors Using the Cold Alkali Process

Carbon Fibers from Wet-Spun Cellulose-Lignin Precursors Using the Cold Alkali Process

Archival performance of paper as affected by chemical components: A Review

Convective Heat Transfer Coefficient of Insulation Paper–Oil Contact Surface of Transformer Vertical Oil Channel

Contact Info

Product

Resources

About