Cellulose optimisation

Considerable research effort has been devoted to developing a new generation of disperse dyes designed to optimise fastness to washing and minimise cross-staining of the cellulosic component of polyester/cellulosic blends [97,98]. Diester-containing monoazo disperse dye structures (4.91) that yield a dicarboxylic acid on hydrolysis and certain thienylazo blues... 

Systematic investigations were carried out for the preparation of cellulose acetate of D.S. 2,65 and other mixed esters which included cellulose acetate-propionate, cellulose acetate-butyrate, cellulose acetate-benzoate and cellulose acetate-methacrylate. The experimental conditions were optimised for maximum yield of the ester. Flat osmotic membranes were developed from these esters and characterised for their osmotic and transport properties. The nmmbra-nes were evaluated in a reverse osmosis laboratory test-cell using 5OOO ppm sodium chloride solution at 40 bars pressure. Table 1 presents the typical performance data of these membranes. 

A study of the influence of the nature of the solid support showed that silica, celite, cellulose or magnesium sulphate in combination with borohydride can also be used successfully in the microwave-assisted reduction of carbonyl compounds. The choice of the solid support has been reported to influence the chemoselectivity of the reduction of chalcone. Under optimised conditions the reduction of the alkene can be suppressed using borohydride on silica, whereas the use of cellulose as solid support seems to favour C=C reduction (Scheme 4.11 )27. 

Disposal of the remainders of finish baths should be done in compliance with local regulations. Some catalysts used with these finishes contain zinc or other metals whose presence in waste water may be restricted. One side benefit of cellulose crosslinking finishes, especially the formaldehyde-containing ones, is increased resistance of the fabric to microbial attack. The effects of wrong condensation conditions for the common dry crosslinking process and steps to their optimisation are listed in Table 5.10. ... 

Elydroxypropyl cellulose (HPC) Soluble in cold water, Gl fluids and polar solvents. Becomes tacky when dried, so is unsuitable for use alone, often used in combination with other polymers to optimise adhesion of coat. 

Cellulosic fibres used for reinforcement in nonpolar thermoplastics, such as PP, have to be modified because effective wetting of fibres and strong interfacial adhesion are required to obtain composites with optimised mechanical properties [31, 32]. Several methods for improvement in the adhesion between polymer and cellulosic fibres have been developed. 

A three-enzyme electrode system, such as needed for creatinine measurement, poses a more difficult enzyme-immobilisation problem, in that different enzymes have different immobilisation requirements and their microenvironmental interrelationships need to be optimised. For one creatine sensor, the requisite creatine amidinohydrolase and sarcosine oxidase were immobihsed in polyurethane pre-polymer and PEG-hnked creatinine amidohydrolase was attached via diisocyanate pre-polymer to create a polyurethane adduct [14]. The likelihood of enzyme inactivation with chemical immobih-sation is high, but provided an enzyme preparation survives this, long-term stability is feasible. In the case of these three particular enzymes, a loss of activity resulted from silver ions diffusing from the reference electrode the material solution was to protect the enzyme layer with a diffusion-resisting cellulose acetate membrane. 

Leh, C. R, Rosli, W. D. W., Zainuddin, Z., Tanaka, R. Optimisation of oxygen delignification in production of totally chlorine-free cellulose pulps from oil palm empty Suit bunch fiber. Industrial Crops and Products 2008,28,260-267. 

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