Homogeneous Grafting of New Amido Groups onto Hydroxyethyl Cellulose Acetate Microfibrils: Solubility Study

Abstract

Attempts to modify the surface of hydroxyethyl cellulose acetate (HECA-DS_AC ~1.5) microfibrils were made using amine terminated molecules. First, the amine compounds were reacted with sebacoyl chloride in nonstoichiometry ratio in order to obtain a monoadduct chloride such as ClCO-(CH₂)₈-CONHR. Then the resulted derivatives were coupled with hydrophobic hydroxyethyl cellulose acetate (HECA) by a condensation reaction in homogenous medium using triethyl amine (N(C₂H₅)₃) in THF. The products were characterized by FTIR, ¹H NMR, ¹³C NMR, and DRX, and thermal proprieties were also determined. The X-ray diffraction showed that the crystallinity of the amido esters obtained depends on both the degree of substitution and the nature of the graft moiety. The solubility study was based on the determination of the Flory–Huggins interaction parameters (χ) using the partial Hansen solubility parameters (HSP) and that were calculated from the Van Krevlen–Hoftyze (VKH) method and the T. Lindvig approximation.

Keywords: cellulose; microfibrils; amidation; Hansen solubility; Flory–Huggins parameters.