Cellulosics, definition

Fig. 4. Glucose production per liter of reactants over time for similar semibatch experiment as shown in Fig. 2, but at a lower enzyme loading of 10 FPU/g of cellulose (definitions of symbols and vertical dashed lines are the same). Error bars represent averages 1 SD for two repeated experiments.

Synonyms Cellulose, 2-hydroxypropyl ether HPC Hydroxypropyl ether of cellulose Hyprolose Oxypropylated cellulose Definition Partially substituted poly(hydroxypropyl) ether of cellulose Properties Off-wh. gran, powd., odorless, tasteless sol. in cold water, methanol, ethanol, many polar org. soivs. insol. in water > 37.7 C ... 

Carboxymethyl) hexadecyidimethylammonium hydroxide, inner salt. See Cetyl betaine Carboxymethyl hydroxyethyl cellulose CAS 9004-30-2 9088-04-4 Synonyms Cellulose, carboxymethyl-2-hydroxyethyl ether, sodium salt NaCMHEC Sodium carboxymethyl hydroxyethyl cellulose Definition Sodium salt of an ethylene glycol ether of cellulose gum... 

Definition Ester of cetyl glycol and isostearic acid Empirical C34H68O3 Uses Emollient in cosmetics Cetyl hydroxyethyl cellulose Definition Ether of cetyl alcohol and hydroxyethylcellulose... 

Synonyms Croscarmellose (INCI) Crosslinked carboxymethyl cellulose Crosslinked cellulose gum Crosslinked CMC Crosslinked NaCMC Crosslinked sodium carboxymethylcellulose Crosslinked sodium CMC Sodium salt of crosslinked carboxymethyl ether cellulose Definition Sodium salt of thermally crosslinked carboxymethylated cellulose Properties Wh. to off-wh. free-flowing powd. odorless partly sol. in water insol. in ether, alcohol, org. soivs. pH 5-7 (1% disp.)... 

Synonyms Cellulose, 2-hydroxypropyl ether HPC Hydroxypropyl ether of cellulose Hyprolose Oxypropylated cellulose Definition Partially substituted poly(hydroxypropyl) ether of cellulose ionic Nature Nonionic... 

Originally, the word rayon was appHed to any ceUulose-based man-made fiber, and therefore included the cellulose acetate fibers. However, the definition of rayon was clarified in 1951 and includes textiles fibers and filaments composed of regenerated cellulose and excludes acetate. In Europe the fibers are now generally known as viscose the term viscose rayon is used whenever confusion between the fiber and the cellulose xanthate solution (also called viscose) is possible. 

Hemicellulose [9034-32-6] is the least utilized component of the biomass triad comprising cellulose (qv), lignin (qv), and hemiceUulose. The term was origiaated by Schulze (1) and is used here to distinguish the nonceUulosic polysaccharides of plant cell walls from those that are not part of the wall stmcture. Confusion arises because other hemicellulose definitions based on solvent extraction are often used in the Hterature (2—4). The term polyose is used in Europe to describe these nonceUulosic polysaccharides from wood, whereas hemicellulose is used to describe the alkaline extracts from commercial pulps (4). The quantity of hemicellulose in different sources varies considerably as shown in Table 1. 

Historically, dietary fiber referred to iasoluble plant cell wall material, primarily polysaccharides, not digested by the endogenous enzymes of the human digestive tract. This definition has been extended to iaclude other nondigestible polysaccharides, from plants and other sources, that are iacorporated iato processed foods. Cellulose [9004-34-6] (qv) is fibrous however, lignin [9005-53-2] (qv) and many other polysaccharides ia food do not have fiberlike stmctures (see also Carbohydrates). 

Rejection Rejection is defined in Background and Definitions. The highest-rejection membranes are those designed for single-pass production of potable water from the sea. The generally accepted criterion is 99.4 percent rejection of NaCl. Some membranes, notably cellulose triacetate fibers are rated even higher. A whole range of membranes is available as rejection requirements ease, and membranes with excellent chlorine resistance and hydrolytic stability can be made with salt rejection over 90 percent. 

Standardized techniques atomic absorption (AAA) and photometric (FMA) of the analysis and designed by us a technique X-Ray fluorescence of the analysis (XRF) for metals definition in air of cities and the working areas of plants to production of non-ferrous metals are applied. The samples of aerosols were collected on cellulose (AFA-HA) and perchlorovinyl (AFA-VP and FPP) filters (Russia). The techniques AAA and FMA include a stage of an acid-temperature ashing of a loaded filter or selective extraction of defined elements from filter by approaching dissolvent. At XRF loaded filters were specimens. 

Refs to nitrated materials, eg Cellulose Nitrate, Cyclonite etc., already described in this Encyclopedia will be found in Sections 11 111 In view of the definition of nitration presented above and the concepts to be developed in Section VIII, discussion of nitrate salts such as H2NNH2.HNG3 or CH3NH2.HN03 etc is not included in this article... 

The, chain voAiantS are characterized by the presence of two abnormal components, an abnormal Hb-F (02 /2) and an abnormal Hb-A (tt2 32) Of these two, the 02 2 component dominates and the 02 32 component Is often difficult to detect. The methods of choice are starch gel electrophoresis and anion-exchange chromatography using DEAE-Sephadex or DE-52 Cellulose. Chain analyses of these Isolated hemoglobin components will lead to a definitive Identification. 

Representative condensation polymers are listed in Table I. The list is by no means exhaustive, but it serves to indicate the variety of condensation reactions which may be employed in the synthesis of polymers. Cellulose and proteins, although their syntheses have not been accomplished by condensation polymerization in the laboratory, nevertheless are included within the definition of condensation polymers on the ground that they can be degraded, hydrolytically, to monomers differing from the structural units by the addition of the elements of a molecule of water. This is denoted by the direction of the arrows in the table, indicating depolymerization. 

For code R8 it commences with a solid with the help of AFNOR standards NF T 20-035 . Handling consists in preparing mixtures of variable compositions of an oxidant to be classified as cellulose. Both substances have to have a definite particle size distribution. The composition which gives the fastest combustion on a moulding of the mixture at a distance of 20 cm is established. This speed is compared with the one of the mixture used as a reference, which has an imposed composition of barium nitrate and cellulose. If the combustion speed of the particular substance is higher than that of the reference, it will bear R8. 

Simply put, paper is manufactured by applying a watery suspension of cellulose fibers to a screen that allows the water to drain and leaves the fibrous particles behind in a web. Most modem paper products contain nonfibrous additives, but otherwise they fall within this general definition. Only a few paper products for specialized uses are created without the use of water, using dry forming techniques. The production of pulp is the major source of environmental impacts from the pulp and paper industry. 

The relation between the end points of the tensile curve, ab and eh (= b), can be calculated with Eqs. 9,23 and 24. This relation is now by definition taken as the fracture envelope. Note that these equations only hold for elastic deformation. In order to account for some viscoelastic and plastic deformation, a value gv is used, which is somewhat smaller than the value for elastic deformation g. The dashed curves in Figs. 8 and 9 are the calculated fracture envelopes (neglecting the chain extension) for the cellulose II and the POK fibres, respectively. These figures show a good agreement between the observed and calculated fracture points. 

There is no major advance which can be reported in our knowledge of protopectinases. The possibility of the existence of a protopectinase different from PG seems now somewhat more remote than it was ten years ago. As stated above, the trend in thinking about protopectin is definitely in the direction that protopectin is not a specific cellulose-pectinic acid compound but pectinic acid which is insoluble either on account of large molecular size or due to the effect of polyvalent cations or both. In this sense there is really no need to assume the existence of a separate protopectinase. There is little doubt that this uncertainty is in a large degree attributable to the lack of precise knowledge of protopectin. 

Sisson has traced the evolution of current concepts of the crystalline part of cellulose structures. The fiber diagram obtained by X-ray diffraction is now known to be produced by a series of elementary crystals, called crystallites, which have a definite arrangement with respect to the fiber axis. It is also known that the crystallites in regenerated cellulose may be oriented to varying degrees with respect to the fiber axis and that the crystallites in regenerated cellulose and mercerized cotton differ from those in native fibers. These hydrate type crystallites appear to be more reactive chemically than the native type. 

It is probable that varying degrees of ordering of chains exist in a cellulosic material and that a sharp differentiation of crystalline and non-crystalline celluloses may not be feasible or even possible. Theoretically, the lateral surfaces of crystallites are amorphous but may have far less importance in determining such properties as strength, flexibility and extensibility than the non-crystalline cellulose which supplies continuity of structure in the direction of crystallite orientation. Yet properties like moisture absorption and swelling may be more dependent upon the amount of cellulose which exceeds a certain degree of disorder (permeability) than upon location. The definition of crystallinity may, therefore, be made ultimately in terms of practical objectives. 

The surface area of fibres increases during refining. However, the definition of surface area for cellulose is not straightforward and it is necessary to define it a little more precisely. It can be measured when the pulp is in either the wet or the dry state and very different... 

It is difficult to find any definitive information that indicates ozone damage as extensive as that suggested in the mri report. The latter identified cotton, nylon, and rayon as particularly susceptible to ozone. The oxidation of cellulose fibers by ozone was the subject of a study in 1952 that showed that dry cotton was not seriously degraded by ambient ozone. In more recent studies, these conclusions were confirmed. The only information available on fibers other than cotton addressed the effect of ozone on modacrylic, acrylic. Nylon 66, and polyester fabrics.The results indicated minimal effects on these fibers. 

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