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Groups, depending on the amount and their distribution along the polysaccharide

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  1. Chlorine are much smaller, and produce pulp in amounts between 1000 and several
  2. Cleavage of the Polysaccharide Chain
  3. Consumption to a make-up in the amount of losses from the cycle. On the other
  4. Depending on the position of the log in the grinder magazine, it can be distinguished
  5. DIFFERENCES IN THE ARTICULATION BASES OF THE ENGLISH AND RUSSJAN CONSONANTS AND THEIR PECULIARITIES
  6. Dissolve out of the cell wall during pulping (macropores). The amount of
  7. Endgroups from the total amount of carbonyls

Chains (see Tab. 11.7, Dissolving pulp characterization). The carboxyl groups,

Mainly derived from uronic acid side chains of hemicelluloses, and aldonic acid

Groups created by the oxidation of reducing end groups, determine the surface

Charge (distribution) and hydrophilicity, which in turn exhibits an influence on

Wettability of the pulp (the ability of the sample to absorb liquids). The carboxyl

Groups relate also to the swelling behavior of a pulp sample, which may be estimated

By the water retention value (WRV). The data in Tab. 11.1 indicate that the

WRV values of the selected pulps differ only slightly. The only significant difference

Is observed for beech kraft pulp, which seems to correlate with the enhanced

Carboxyl group content. The carbonyl group content of a pulp is made up of the

Reducing end-groups and oxidized groups such as keto and aldehyde groups,

Which are introduced by pulping and bleaching operations. The reliable and accurate

Determination of those oxidized structures in cellulose remains a major challenge.

A novel method based on fluorescence labeling with carbazole-9-carboxylic

acid [2-(2-aminooxyethoxy)ethoxy]amide (CCOA) allows the precise evaluation of

Paper-Grade Pulp

The carbonyl groups relative to the molecular weight, as it is combined with gelpermeation

chromatography (GPC) measurement [20,21]. Even though the average

Molecular weight is higher for sulfite pulps, their carbonyl group content is

Considerably higher as compared to kraft pulps (see Tab. 11.1). It may be assumed

That the high carbonyl content of sulfite pulps originates from low molecularweight

Hemicelluloses and oxidized groups along the cellulose chain. In a first

Approximation, the carbonyl group profile may be estimated by subtracting the

Contribution of the reducing end groups from the total amount of carbonyls,

Assuming that the amount of reducing end groups relates to the number average

molecular weight determined from GPC measurement [22]. The pattern of carbonyl

Groups along the polysaccharide chains has been determined for the hardwood

Paper pulps to obtain a first indication about the influence of pulping processes

On the generation of carbonyl groups. Figure 11.2 indicates that the major

Part of the carbonyl groups in the beech sulfite pulp is centered around a molecular

weight of about 13 kDa (DP ~80), whereas in both hardwood kraft pulps the

Maximum of carbonyl groups introduced along the polysaccharide chains is

shifted to a higher molecular weight (32 kDa or DP ~200).

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Читайте в этой же книге: Charged polymers can be used for a further intensification. This process reduces | Complex and a cobalt salt. | Increase pollution by causing a higher demand for a chemical to achieve identical | Fifteen years of development. Pulp Paper | To applications such as newsprint, toilet tissues, and paperboard as they tend to | Be transferred to paper-grade pulps. The papermaking properties of pulp are | Acid side chains. The glycosidic bond between uronic acid and the xylan backbone | High LODP, the high modulus in the stress-strain curve, the excellent swelling | Of chemical paper pulps, including TCF and ECF variants for both softwood | Be expected when high dosages of, for example, ozone, or other bleaching chemicals |
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Is rather unstable in acid sulfite pulping, and this results in a low (hemicellulose)| Beech Sulfite Beech Kraft Eucalyptus Kraft

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