Cellulose, properties

Refining and Fractionation. These processes are used to alter and select cellulose properties so the final sheet has the desired properties (51). Properties of recycled fibers differ from those of fibers prepared directly from wood. For example, recovered chemical fibers have lower freeness, an apparent viscosity leading to different water drainage characteristics on paper machines. Recovered fibers also have iacreased apparent density, lower sheet strength, iacreased sheet opacity, inferior fiber—fiber bonding properties, lower fiber sweUiag, lower fiber flexibiUty, lower water reteatioa, reduced fiber fibrillatioa, and much lower internal fiber delamination. 

The viscosity range of CN products can be adjusted in advance by choosing the starting cellulose with an appropriate degree of polymerization (DP). A study of the different celluloses examined the impact of various cellulose properties, such as morphological factors (percent crystallinity, fiber length, and distribution), chemical composition (DP, ash content), and hemiceUulose and lignin content, on the nitration behaviors of cellulose (55). 

In terms of paper conservation, this work is of value since it is an attempt to determine (i) if UV and EB grafting times for cellulose copolymerization can be shortened significantly by the inclusion of appropriate additives and (ii) if such a process is capable of incorporating into cellulose properties required for preservation, particularly wet and dry strength and flexibility. These studies also should indicate the feasibility of extrapolating data from the present solvent grafting systems to processes based on solvent-free, rapid-cure UV and electron beam (EB) which are the ideal polymerization conditions for preservation applications. 

Effect of interaction of acid and cellulose at the stages of impregnation and thermal pretreatment depends on the cellulose properties. The celluloses under study have different ratios of ordered and amorphous regions. They differ also by their degree of polymerization (Table 1) and hydrophilic properties. The presence of phosphoric acid affects the system of the cellulose hydrogen bonds, the crystallinity index and leads to the formation of esters [11,12, 19],... 

K. E. Almin and K. E. Eriksson, Influence of carboxymethyl cellulose properties on the determination of cellulase activity in absolute terms, Arch. Biochem. Biophys., 124 (1968) 129-134. 

Features Replaces attapulgite 1 1 ratio in most applies. improves hiding and wet edge props., hold-out esp. with cellulosics Properties Off-wh. 98% -200 mesh bulk dens. 30 Ib/fP (loose), 45 Ib/ft (packed) pH 9.5 (10% slurry) 8% moisture Bentolite D [Southern Clay Prods.]... 

Definition Ethylene glycol ether of ethyl cellulose Properties Wh. gran, solid sol. In water sol. In mixt. of aliphatic hydrocarbons contg. alcohol Precaution Combustible... 

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 ... 

Synonyms Carbohydrate gum Cellulose hydroxypropyl methyl ether Cellulose 2-hydroxypropyl methyl ether HPMC Hypromellose Methyl hydroxypropyl cellulose MHPC Definition Propylene glycol ether of methyl cellulose Properties Wh. gran, powd. sol. in most polar soivs., cold water swells in water to produce a clear to opalescent vise, colloidal sol n. insol. in hot water and in anhyd. alcohol, ether, chloroform nonionic Toxicoiogy LD50 (IP, rat) 5200 mg/kg mildly toxic by IP route TSCA listed... 

The property profile of cellulose-based plastics and cellulose products used in typical plastics applications covers a broad range where the intrinsic cellulose properties can be recognized to different degrees. So, hydrophilicity is a prominent feature for pure cellulose products, which is reduced as the number of ester substituents and their chain length is increased. Equilibrium moisture content of cellulose fibres, for example, is around 12% while the moisture regain of diacetate fibres is 6.5% and of triacetate fibres 3.2% [43]. In this respect, propionic and butyric esters are superior when fully substituted, but even mixed esters of the CAP and CAB types... 

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.)... 

Definition Ethyl ether of cellulose Properties Wh. to It. tan powd. sol. in most org. liqs., alcohol, aromatic soivs. insol. in water, glycerol, propylene glycol dens. 1.07-1.18 ref. index 1.47... 

Definition Methyl ether of cellulose Properties Grayish-wh. fibrous powd., odorless, tasteless aq. suspension swells in water to vise, colloidal sol n. sol. in cold water, glacial acetic acid, some org. soivs. insol. in alcohol, ether, chloroform, warm water m.w. 86,000-115,000 Toxicoiogy LD50 (IP, mouse) 275 g/kg LDLo (IV, mouse) 1 g/kg poison by IP route nonallergenic may cause immune responses TSCA listed... 

Synonyms Cellulose gel MCC Dehnition Isolated, colloidal crystalline portion of cellulose fibers partially depolymerized acid hydrolysis prod, of purified wood cellulose Properties Wh. fine cryst. powd., odorless partly sol. with swelling in dil. alkali insol. in water, dil. acids, and most org. soivs. bulk dens. 18-19 Ib/ft ref. index 1.55 pH 5-7 Toxicology LD50 (oral, rat) > 5 g/kg, no significant hazard irritant by inhalation (dust) may be damaging to lungs TSCA listed... 

Bacterial cellulose properties and suitability as a medical implant for cartilage tissue engineering... 

In this Chapter, the structure and properties of cellulose materials are discussed furthermore, in order to predict the cellulose properties, their dependence on the primary structural parameters is described. 

Uses Fixing agent for direct dyes on cellulosics Properties Liq. 

This emphasizes the need for suitable modification or derivatization of cellulose for its versatile and widespread use as a membrane material. Chemical modification alters cellulose properties with respect to elasticity, hydrophilicity, ion exchange or adsorption capacity, water uptake capacity, thermal, and microbial resistance. The reactive primary and secondary hydroxyl groups in its backbone structure serve as potential sites for the introduction of different functional groups. The possible modifications include etherification, esterification (Marchetti et al. 2000), oxidation,... 

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