SYNTHESIS AND CHARACTERIZATION OF CARBOXYMETHYLATED CORNSTARCH

Аннотация

The aim of this study is preparation and characterization of carboxymethylated cornstarch (CMCS)
for potential application as water based drilling fluids. The cornstarch was modified by sodium monochloroacetate.
The structure of cornstarch and CMCS was established by H1
NMR and FTIR spectroscopy. The degree of
carboxymethylation of cornstarch determined by H1
NMR spectroscopy was equal to 80%. The viscosity-average
molecular weights (M) of pristine cornstarch and CMCS calculated from Mark-Kuhn-Houwink equation [ߟ=[KMa
are equal to 2.15·103 gmol-1 and 2.75·105 gmol-1 respectively. The temperature dependent viscosity of CMCS was
measured in water by Ubbelohde viscometer, while the rheological properties of CMCS in dependence of polymer
concentration and ionic strength of the solution were evaluated by rheoviscometer. The thermal characteristics of
samples were determined by differential scanning calorimeter (DSC) and thermogravimetric (TGA) and differential
thermal analyzer (DTA). The morphological properties of cornstarch and CMCS were studied by scanning electron
microscopy (SEM). The structural-mechanical, filtration and filter cake forming properties of drilling fluids and fluid
loss indicators of CMCS were found