Acetylation of Cellulose Nanocrystals Extracted from Cotton for Drilling Fluid Application: Structural and Thermal Characterization.

In petroleum exploration, cellulose derivatives such as carboxymethylcellulose (CMC) are frequently used in drilling, cementing and fracturing fluids. However, under extreme drilling conditions, these additives have limited performance. In this regard, cellulose nanocrystals particles (CNCs) which are also derived from cellulose material are a suitable candidate due to their shear thinning rheology and thixotropy properties, even at low concentrations, among so many properties thanks to their crystalline structure and their nanometric dimensions. In this work, hydrolyzed fibers from industrial cotton are acetylated using acetic anhydride and sulfuric acid as catalysts, with the aim to modify surface properties of the obtained CNCs without changing their fiber structure and morphology. FTIR analysis pointed out the acetylation success of the obtained nanocrystals whose dimensions were found to be unaltered by the modification process. SEM images of cotton nanocrystal indicate that CNCc surface modification preserves the nanoscale dimensions of the nanoparticles. Also, TGA analysis showed thermal stability for the acetylated CNCc. [ABSTRACT FROM AUTHOR]