Cellulose Esters, Organic Esters

Abstract

AbstractCellulose is one of nature's most abundant structural materials, providing the primary framework of most plants. For industrial purposes cellulose is derived from two primary sources, cotton linters and wood pulp. Cellulose esters are commonly derived from natural cellulose by reaction with organic acids, anhydrides, or acid chlorides. Cellulose esters of almost any organic acid can be prepared, but because of practical limitations esters of acids containing more than four carbon atoms have not achieved commercial significance. Cellulose acetate is the most important organic ester because of its broad application in fibers and plastics; it is prepared in multi‐ton quantities with degrees of substitution (DS) ranging from that of hydrolyzed, water‐soluble monoacetates to those of fully substituted triacetate. Although cellulose acetate remains the most widely used organic ester of cellulose, its usefulness is restricted by its moisture sensitivity, limited compatibility with other synthetic resins, and relatively higher processing temperature. Cellulose esters of higher aliphatic acids, C3and C4, circumvent these shortcomings with varying degrees of success. Mixed cellulose esters containing acetate and either the propionate or butyrate moieties are produced commercially in large quantities by Eastman Chemical Co. in the United States. The properties, manufacturing methods, uses, economics, and safety of organic esters of cellulose are discussed.