Study of Structural Characteristics of Cellulose Esters with Different Degrees of Substitution

In this article, structural characteristics of amorphous mono-, di-, andtri-substituted esters of cellulose have been studied. These esters weresynthesized under homogenous conditions using anhydrides of variousaliphatic acids. The specific gravity of the highly substituted samples wasmeasured by a pycnometric method in the aqueous medium. To calculatethe molar, Van der Waals, and free volumes, as well as the packingcoefficient of amorphous esters the method of additive contributions ofpartial volumes of atoms and atom groups in the volumes of polymerswas used. Based on the molar volume, also specific gravity of celluloseesters was calculated. The coincidence of calculated and experimentalcharacteristics was shown. In addition, the relationship between glasstransition temperature and free volume was found for the esters. Thetheoretical equations were derived, which provide predicting the structuralcharacteristics of cellulose esters with different degrees of substitution.