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Quantitative determination of organic and inorganic impurities completes the analytical
Characterization of a dissolving pulp.
The quality profile of dissolving pulps is comparatively evaluated in the following
Sections of this chapter, according to the following scheme (see Tab. 11.4).
Tab. 11.4 Characterization scheme of dissolving pulps.
Pulp Origin, Pulp Consumers
Chemical properties (molecular level)
Chemical composition
Organic compounds
Carbohydrates
Extractives
Residual Lignin
Inorganic compounds
Macromolecular properties
Molar mass, Molar mass distribution
Functional groups
Supramolecular structure
Crystallinity, Crystallite dimensions
Lattice transition to sodium cellulose I
Cell wall structure
Distribution of hemicelluloses across the fiber wall
Fiber morphology
Pore structure, Accessibility
Degradation of dissolving pulps
Alkaline oxidative degradation (ageing)
Radiation degradation (electron beam treatment)
Overall pulp specification
Pulp Properties and Applications
11.3.2
Dissolving Pulp Characterization
Pulp Origin, Pulp Consumers
Despite much effort to develop alternative pulping routes, dissolving pulp is still
Solely produced by acid sulfite and prehydrolysis kraft processes. The most promising
Alternative processes under development are organosolv processes such as
that originally proposed by Kleinert in 1931 [5] and further developed by Peter and
Hoglinger using only a mixture of ethanol and water [6]. Other approaches
include the recently evaluated Formacell procedure [7], as well as the prehydrolysis-
ASAM (alkaline sulfite with anthraquinone and methanol) and prehydrolysis-
ASA (alkaline sulfite process) processes which enable the manufacture of highpurity,
High-viscosity dissolving pulps due to their high purification and delignification
selectivity [8]. The progress in kraft cooking during the past two decades
Owing to the principles of modified cooking has formed the basis for the development
of the new Visbatch© and VisCBC processes, both of which combine the
Advantages of displacement technology and steam prehydrolysis (see Section
These new environmentally friendly pulping processes are characterized
By their short cover-to-cover times, low energy requirements and very homogeneous
And high product quality, and promote a gradual shift from traditional softwood
sulfite pulps to hardwood prehydrolysis kraft pulps [9].
Despite the world production of dissolving pulp having been reduced constantly
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As resins or inorganic compounds can adversely affect the filterability of viscose, | | | In the past, the latest forecasts reveal a slight change in this trend (see Chapter |