Synthesis, characterization and properties of novel cellulose derivatives containing phosphorus: cellulose diphenyl phosphate and its mixed esters

Using ionic liquid 1-allyl-3-methylimidazolium chloride as reaction medium, a series of novel cellulose esters containing phosphorus including cellulose diphenyl phosphate (C-Dp) and cellulose acetate (CA)-diphenyl phosphate mixed esters was synthesized homogeneously. The degree of substitution was well controlled by altering reaction conditions, such as the molar ratio of the acylating reagents/ anhydroglucose unit and reaction time. The structure and thermal properties of cellulose esters were characterized by FTIR, NMR, wide-angle X-ray powder diffraction and differential scanning calorimetry. All the products possessed excellent solubility in some common organic solvents, and transparent films of cellulose esters were obtained by solution casting. In contrast to C-Dp, CA-diphenyl phosphate mixed esters showed clear glass transitions. More interestingly, these cellulose mixed esters exhibited thermoplastic behavior and could be processed by traditional melt processing methods.