DEGREE OF CRYSTALLINITY OF LIGNOCELLULOSE FROM RICE STRAW AND ITS MODIFICATION PRODUCT
Rubrics: 2. CHEMICAL TECHNOLOGY
Authors:
1.
Kazanskiy nacional'nyy issledovatel'skiy tehnologicheskiy universitet
(Tehnologii sinteticheskogo kauchuka, Assistent)
2.
FGBOU VPO «KNITU»
3.
KNITU
Type:
Article
Pages:
from 39
to 45
Status:
In work
Language:
Russian
Keywords:
RICE STRAW, LIGNOCELLULOSE, IR SPECTROSCOPY, DIFFRACTOMETER, CARBOXYMETHYLATION
Abstract (English):
Cellulose and its modification products are valuable raw materials for creating functional materials. An important characteristic determining the reactivity of cellulose and its properties is the degree of crystallinity. In this work the degree of crystallinity of lignocellulose obtained from rice straw and carboxymethylated lignocellulose was determined. The choice of the study subject is due to the fact that rice straw is a multi-tonnage waste generated annually. Meanwhile data on the extraction of cellulose from rice straw and the properties of the isolated product are not sufficiently complete in the literature. The original rice straw sample contained 49,7 % α-cellulose, 17,2 % lignin and 3,5 % ash. Alkaline pulping method with pre-milling was used to extract cellulose from rice straw. The method was chosen due to the fact that in alkaline treatment, lignin is selectively removed without destruction of carbohydrates, increasing porosity and surface area. A product containing 89,2 % cellulose and 6,7 % lignin was obtained. Carboxymethylation of the extracted lignocellulose was activated using ultra-high frequency microwave radiation. The use of microwave radiation to activate the carboxymethylation process reduced the reaction time by 3-fold, making the method more cost-effective and efficient. The activation time for the alkaline treatment step was 90 sec. at 350 W power. Monochloroacetic acid was used in the esterification step. In the interaction step between lignocellulose and monochloroacetic acid, the microwave activation time was 90 sec at 350 W power. The degree of carboxymethylation was 0.5. The degree of crystallinity of lignocellulose and carboxymethylated lignocellulose was determined using IR spectroscopy and X-ray diffraction analysis. The IR spectroscopy method used the analysis of the intensities of the 900, 1370, 1430 cm-¹ absorption bands versus the intensity of the 2900 cm-¹ band to determine the degree of crystallinity. The degree of crystallinity of lignocellulose obtained from rice straw was found to be about 80 %. The degree of crystallinity of carboxymethylated lignocellulose is reduced by about 20 %. X-ray diffraction analysis confirmed the decrease in the degree of crystallinity of lignocellulose upon carboxymethylation.
Cellulose and its modification products are valuable raw materials for creating functional materials. An important characteristic determining the reactivity of cellulose and its properties is the degree of crystallinity. In this work the degree of crystallinity of lignocellulose obtained from rice straw and carboxymethylated lignocellulose was determined. The choice of the study subject is due to the fact that rice straw is a multi-tonnage waste generated annually. Meanwhile data on the extraction of cellulose from rice straw and the properties of the isolated product are not sufficiently complete in the literature. The original rice straw sample contained 49,7 % α-cellulose, 17,2 % lignin and 3,5 % ash. Alkaline pulping method with pre-milling was used to extract cellulose from rice straw. The method was chosen due to the fact that in alkaline treatment, lignin is selectively removed without destruction of carbohydrates, increasing porosity and surface area. A product containing 89,2 % cellulose and 6,7 % lignin was obtained. Carboxymethylation of the extracted lignocellulose was activated using ultra-high frequency microwave radiation. The use of microwave radiation to activate the carboxymethylation process reduced the reaction time by 3-fold, making the method more cost-effective and efficient. The activation time for the alkaline treatment step was 90 sec. at 350 W power. Monochloroacetic acid was used in the esterification step. In the interaction step between lignocellulose and monochloroacetic acid, the microwave activation time was 90 sec at 350 W power. The degree of carboxymethylation was 0.5. The degree of crystallinity of lignocellulose and carboxymethylated lignocellulose was determined using IR spectroscopy and X-ray diffraction analysis. The IR spectroscopy method used the analysis of the intensities of the 900, 1370, 1430 cm-¹ absorption bands versus the intensity of the 2900 cm-¹ band to determine the degree of crystallinity. The degree of crystallinity of lignocellulose obtained from rice straw was found to be about 80 %. The degree of crystallinity of carboxymethylated lignocellulose is reduced by about 20 %. X-ray diffraction analysis confirmed the decrease in the degree of crystallinity of lignocellulose upon carboxymethylation.
Keywords:
RICE STRAW, LIGNOCELLULOSE, IR SPECTROSCOPY, DIFFRACTOMETER, CARBOXYMETHYLATION
RICE STRAW, LIGNOCELLULOSE, IR SPECTROSCOPY, DIFFRACTOMETER, CARBOXYMETHYLATION
