Cellulose relationships

Table 1. Relationship of Cellulose Acetate DS to Acetyl Content and Combined Acetic Acid...

Other two-dimensional techniques, such as COSY (122), DEPT (123), HOHAHA, soHd state (124) etc. give varying degrees of success when apphed to the stmcture-property relationship of cellulose triesters. The recent appHcation of multiple-bond correlation (HMBC) spectroscopy for... 

Figure 8. Microchromatography on DEAE-cellulose. The relationship between the total hemoglobin levels and the levels of Hb-A2 (Macedonia survey).

Figure 8. Relationship of cellulose, olginic acid, and pectic acid...

Oxidative bleaching of wool is invariably carried out with hydrogen peroxide. The active species involved is likely to be the same as on cellulosic substrates but specific reactions with wool amino acid residues must be considered. The primary reaction is oxidation of cystine disulphide bonds leading to the formation of cysteic acid residues (Scheme 10.41). The rupture of disulphide crosslinks, with attendant increase in urea-bisulphite and alkali solubility values, adversely affects fibre properties. As the severity of bleaching conditions increases, the urea-bisulphite solubility remains little changed but the relationships between alkali solubility and cysteic acid (Figure 10.36) and between cystine and cysteic acid (Figure... 

Takano, T. and Nakatsubo, F. (2010) Synthesis and structure/property relationships of regioselective 2-0-, 3-0-and 6-O-ethyl celluloses. Macromolecular Bioscience, 10, 638-647. 

Epstein and Yapp [4] state "it is obviously necessary to calibrate more specifically the relationship between 6(D) records in cellulose nitrate from tree-ring records and known climatic records. This can probably be done best by the analysis of tree rings from widely different, well-documented environments. Such data will allow the comparison of a large variety of trees and determine the versatility of using the isotopic method for climatic temperature determination". We concur with this statement as long as "from the same population" is inserted. 

Markham and Benton model, 1 628 Mark-Houwink coefficients for cellulose, 20 558t for PBT, 20 64t for PET, 20 58 for PTT, 20 69t Mark-Houwink constants, for poly(ethylene oxide), 10 677t Mark-Houwink equation, 19 717, 839 Mark-Houwink relationship, 10 675 ... 

These are the only ranges of precursor products in the Colour Index that are still commercially significant. Azoic dyes have a close formal relationship to those monoazo pigments derived from BON acid or from acetoacetanilides (section 2.3.1) and some are chemically identical with them, although they are used in a totally different way. Azoic components are applied to produce insoluble azo dyes within the textile substrate, which is almost always cotton. Corresponding azoic components for the dyeing of cellulose acetate, triacetate and polyester fibres were once commercially important, but are now obsolete because of environmental hazards and the time-consuming application procedure. 

A full interpretation of the relationships between direct or vat dye structure and substantivity for cellulose must take into account the contribution of multilayer adsorption of dye molecules within the pore structure of the fibre [71]. The great difference in substantivity between Cl Direct Red 28 (3.66) and the monoazo acid dye (3.67) that is the half-size analogue of this symmetrical disazo dye may be interpreted in terms of their relative tendencies to form multilayers within the fibre pores as a result of dye-dye aggregation. Saturation adsorption values of these two dyes on viscose fibres at pH 9 and 50 °C corresponded to monolayer coverage areas of approximately 90 and 11 m2/g of internal surface respectively [72]. In view of the smaller molecular area and greater mobility of the half-size acid dye, higher uptake than the direct dye would be anticipated if there were only a limited area of internal surface available for true monolayer adsorption. 

Measurements of aqueous solubility and partition coefficient between cellulose acetate and water were compared for thirty disperse dyes and an approximate inverse relationship was postulated [60]. This can only be valid to a limited extent, however, because the partition ratio also depends on the saturation solubility of the dye in cellulose acetate. This property varies from dye to dye and is not directly related to aqueous solubility. The solubilities of four dyes in a range of solvents were compared with their saturation values on cellulose acetate. Solubilities in benzene showed no significant correlation. With the other solvents the degree of correlation increased in the order ethanol < ethyl acetate < 20% aqueous diethylene glycol diacetate (CH3COOCH2CH2OCH2CH2OCOCH3). The last-named compound was suggested as a model with polar groups similar to those in cellulose acetate [86]. 

There is a roughly inverse relationship for a series of structurally related dyes between the time of half-dyeing and the saturation solubility in an appropriate substrate, as illustrated for several 4-alkylamino derivatives of 1-anilinoanthraquinone on cellulose acetate (Table 3.17). It is interesting that methylamino and 2-hydroxyethylamino substituents confer good solubility in this substrate, but ethylamino groups are even less effective than isobutylamino groups in this respect [114]. 

The relationship between dye-fibre bonding and light fastness was examined for ten sulphatoethylsulphone reactive dyes on cellulose and it was shown that the stronger the bonding between dye and substrate, the more stable was the dyeing when exposed to light... 

Both Tg and the activation energy below Tg Increase with cation size (Table VI). The activation energy values for p-Cl-PHMP compare favorably with the results of 1on conductivity measurements 1n cellulose acetate (16.18). shown 1n Figure 8. This relationship speaks strongly for cation diffusion as being Involved in the rate determining step. 

The final product was subjected to ferric chloride-hydrochloric acid treatment in the same manner as commercial glucose and starch. A linear carbon dioxide-time relationship was observed which was practically identical with that for starch. In other words purified cotton cellulose, on relatively complete hydrolysis, appeared to give glucose in a... 

The character of the carbon dioxide-time curves for unsubstituted celluloses made impossible the use of simple graphical methods. It was found,22 however, that the data gave reasonably straight lines on logarithm-logarithm paper and the following scheme was employed to obtain estimates of the apparent hydrolysis. Glucose was assumed to be represented by the linear relationship... 

The word cellulosan has the disadvantages that (a) it employs an ending ordinarily used for designating simple anhydro-sugars, and (b) that the name implies a relation with cellulose, whereas in fact no relationship is intended and polysaccharides placed in this class are quite different from cellulose in both composition and properties. Their connection with cellulose seems to be only that they occur with cellulose as constituents of the plant cell wall. 

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