Synthesis of cross-linked highly substituted cationic starches and study of their thermo-oxidative stability in a model environment

C. M. Butrim¹, T. D. Bil’dyukevich¹, N. S. Butrim¹, V. V. Litvyak², M. F. Nikitina², L. B. Kuzina^2
1Research Institute for Physical Chemical Problems, Belarusian State University, ul. Leningradskaya, 14, g. Minsk, 220030, Respublika Belarus’
²All-Russian Research Institute of Starch Products, branch of the Gorbatov Federal Science Center of Food Systems, Russian Academy of Sciences, ul. Nekrasova, 11, pos. Kraskovo, Lyuberetskii r-n, Moskovskaya obl., 140051, Russian Federation

Abstract. The purpose of this work was to synthesize cross-linked highly substituted cationic starches (potato and corn), to study their thermo-oxidative stability in a model environment, and to assess the possibility of using them as flocculants in drilling fluids. We obtained cross-linked cationic starches dispersible in cold water with a high degree of substitution (0.183 mol/mol for potato and 0.174 mol/mol for corn) and high viscosity of their aqueous dispersions (2500–7000 mPa∙s for potato starch and 2250–5500 mPa∙s for corn). The thermo-oxidative stability of the synthesized cross-linked highly substituted cationic starches was investigated by the results of changes in the dynamic viscosity of aqueous solutions at 45 C for 28 days at a constant shear rate of 5.6 s-1 using a model solution of fresh water as a solvent (NaCl – 0.14 g/L, CaCl2 – 0.19 g/L). Test conditions were the following: polymer concentration was 0.2%; oxygen concentration was equilibrium. At the first stage of the experiment (within 7 days of exposure of starch solutions), the dynamic viscosity dropped sharply compared to the initial level. In this case, the cross-linked cationic potato starch lost 10–11% of the initial viscosity and the cross-linked cationic corn starch lost 14–15% of the initial viscosity depending on the type of cross-linking agent used. For uncrosslinked cationic potato and corn starches, the decrease in dynamic viscosity in 7 days of storage was significantly higher – 44.3% and 38.5%, respectively. Cationic potato starches cross-linked with epichlorohydrin (ECH) at the doses of 0.5% and 1.0% as well as sodium trimetaphosphate cross-linked with ECH at doses of 0.5% and 5.0% were the most resistant to thermo-oxidative destruction under the studied conditions. In 28 days, the decrease in the dynamic viscosity of samples of cross-linked cationic potato starch made at the indicated doses of cross-linking agents did not exceed 20% of the initial value.

Keywords: starch; cationization; cross-linking; epichlorohydrin; sodium trimetaphosphate; viscosity; thermo-oxidative stability.

Author Details: C.M. Butrim, Cand. Sc. (Chem.), leading research fellow; T.D. Bil’dyukevich, Cand. Sc. (Chem.), senior research fellow; N.S. Butrim, research fellow (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); V.V. Litvyak, D. Sc. (Tech.), Cand. Sc. (Chem.), leading research fellow; M.F. Nikitina, research fellow; L.B. Kuzina, postgraduate student, research fellow (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.).

For citation: Butrim CM, Bil’dyukevich TD, Butrim NS, at al. [Synthesis of cross-linked highly substituted cationic starches and study of their thermo-oxidative stability in a model environment] Dostizheniya nauki i tekhniki APK. 2020; 34(11): 104-10. Russian. doi: 10.24411/0235-2451-2020-11116.