Investigation of the influence of double modification of starch as of natural polymer, on rheological characteristics of compositions and their film-producting properties

Abstract

Starch is a natural polymer that has unique properties, which consist of the annual renewal of raw materials and the ability to create biodegradable materials based on starch. Modification of starch leads to changes in its chemical structure, which is associated with both the method of modification and the introduction of active chemicals into its structure. Double modification occurs due to the simultaneous use of physical or mechanical method with the addition of the necessary chemicals. Physical methods of starch modification include microwave and ultrasonic irradiation. The aim of the work was to study the physicochemical properties of corn starch after double modification and its use in the creation of film-forming samples. The urgency of this work is due to the need that in order to protect the environment the basis of technological compositions used in industry should be natural polymers, this will minimize the negative impact on the environment and develop environmentally friendly compositions and functional systems for various purposes. The structure of two types of corn starch was studied by pyrolytic mass spectrometry and their characteristic mass spectra were determined. The influence of physical modification by ultrasonic and microwave irradiation of corn starch using plasticizing additives based on modified soybean and rapeseed oils on the rheological properties of the compositions, solubility and swelling was studied. It was found that the modification of starch using ultrasonic irradiation leads to a significant decrease in dynamic viscosity, while after microwave irradiation the viscosity increases. Double-modified corn starch was investigated for the formation of film-forming materials with the addition of NaКMC and polyvinyl alcohol. The strength characteristics of the films of the compositions are determined.