Cellulose derivatives hydroxypropylcellulose ester

An ester of cellulose, the hydroxypropylcellulose (HPC), was chosen among the several cellulosic derivatives which can be used as matrix materials. HPC is readily available, inexpensive and soluble in a wide variety of common organic solvents. As reinforcement, Avicel fibers (/ = 30 pm and Ijd = 5) were used. Cross-linking was achieved using several aliphatic or aromatic diisocyanates [13]. It is worth mention that general trends concerning the mechanical and gas barrier properties were similar for all cross-linked composites, and for that reason we refer to those that have been cross-linked with 1,4-butyldiisocyanate (BDI). 

Hydroxyethylcellulose (HEC) and hydroxypropylcellulose (HPC) are prepared by nucleophilic ring opening of ethylene oxide and propylene oxide, respectively, by the hydroxyl anions on the anhydroglucose ring of cellulose. Reactions are conducted commercially in caustic aqueous slurry processes (72). Laboratory methods recently have been reported for preparation of cellulose ethers, esters, and carbamates imder homogeneous reaction conditions in organic solvents (88-91). Such solvents may lead to development of new commercial processes for cellulose derivatives with more imiform substitution. 

Since the hydroxyl groups in cellulose are reactive and can be easily functionalized, cellulose has been made into a large number of derivatives in the form of ethers, esters, and acetals, such as methyl cellulose, hydroxypropylcellulose, hydroxypropyl methyl cellulose, and carboxymethyl cellulose. These cellulose derivatives are soluble in a variety of solvents and can be easily processed into various forms, such as... 

Cellulose is a fibrous, tough, water-insoluble, and crystalline substance. As a result of these characteristics, it is often converted to its derivatives in order to make it more useful. The most commonly used derivatives of cellulose are carbox-ymethylcellulose, methylcellulose, hydroxyethylceUulose, hydroxypropylcellulose, cellulose acetate, and cellulose xanthate (12). Among these derivatives, cellulose acetate and cellulose xanthate are cellulose esters, which are now widely used in the manufacturing of fibers, films, and in injection molding thermoplastics. 

Acrylic acid derivates/ esters Carboxymethyl cellulose (CMC) Ethylcellulose (EC) Hydroxypropylcellulose (HPC) Hydrox5 ropylmethylcellulose (HPMC) Methylcellulose (MC)... 

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