Nurzat ŞAYKİYEVA | Kubat KEMELOV | Mirlan MOLDOBAYEV | Canıl İSKAKOVA | Mustafa DOLAZ

Article | 2023 | Cellulose Chemistry and Technology57 ( 3-4 )

This study aims to evaluate and reuse defective products and cotton wastes resulting from factories producing socks in Bishkek, Kyrgyzstan, in order to solve the issues related to their disposal. For this purpose, microcrystalline cellulose (MCC) was obtained after isolating the cellulose from these wastes by treating them with sulfuric acid solutions. Then, under constant NaOH and monochloroacetic acid (MCA), CMC with the highest DS value of (0.65) was synthesized at 65 degrees C for 2 hours. When the reaction time was increased (3, 4 and 5 hours) at the same temperature, the DS value decreased by 0.39, 0.28, and 0.26, respectively . . .. FT-IR, NMR, and XRD spectroscopic methods were used to characterize the structure of CMCs. SEM was used to investigate surface morphologies, and DTA-TG to examine thermal stability. In addition, the obtained CMCs were used as coatings for apples and tomatoes, and parameters such as weight loss, firmness, total soluble solids and ascorbic acid in uncovered and covered tomatoes and apples, were investigated; also, microbial analysis, and sensory analysis were performed. These analyzed parameters were improved for tomatoes and apples coated with CMC, compared with those uncoated. Keywords: recovery, carboxymethyl cellulose, NMR, storage quality, microbial loa More less

Mustafa DOLAZ

Article | 2022 | Cellulose Chemistry and Technology56 ( 1-2 )

This study aimed at the recovery of cellulose from abundantly available wastes and its sustainable application. Firstly, in the cleaning process, cellulose-containing wastes, such as air particle vacuum powder (APVD), towel clippings (TC), and cottonseed delintation residues (CD), were thoroughly washed, separately, with tap water to remove some organic and inorganic impurities. The cotton slurry was purified by 17.5 NaOH at 90 degrees C for about 4 hours, then filtered and washed with tap water. Afterwards, the resulting pulp was bleached by NaOH and H2O2 , and washed with distilled water until neutralized. Secondly, for the synthe . . .sis of carboxymethyl cellulose (CMC) from the above-dried celluloses, optimum conditions were achieved by varying the concentrations of components and ambient conditions. In the sample coded TCCMC3, a maximum degree substitution (DS) of 1.22, the highest consistency, the highest penetration time and the highest viscosity with 2520 centipoises (cP) were obtained from the reaction of towel clippings with 5.62 g sodium hydroxide and 13.12 g monochloroacetic acid (MCA) at 65 degrees C for 3 hours. Finally, the effect of these synthesized CMCs on the consistency and penetration time of a cement paste was investigated. The consistency of standard Portland cement (PC), without CMC addition, was 5 mm in the Vicat test, while the values measured for the cement pastes to which TCCMC3, APVD(CMC3) and CDCMC3 were added reached 36.5 mm, 28.0 mm and 13.0 mm, respectively. While the setting time in the standard sample (Portland cement paste, PCP) was between 2.20-4.10 hours, this time shifted to 3.30-7.00 hours, with a maximum setting time recorded with the addition of TCCMC3. Besides, while the penetration time for APVD(CMC3) started at 3.10 hours and was completed at 5.30 hours, for CDCMC3, it ranged between 2.40 and 4.40 hours, leaving it without hydration in a higher time interval than in the case of standard Portland cement paste. As a result, it has been found that carboxymethyl cellulose synthesized by the etherification reaction of cellulose obtained from recycled wastes for industrial uses, in an aqueous alkali environment, can be applied as a thickener in the construction industry and other fields More less

Mustafa DOLAZ

Article | 2022 | Cellulose Chemistry and Technology56 ( 5-6 )

Unfortunately, cellulose, which is the most abundant of natural polysaccharides in the world, and is found in high amounts in cotton and the waste/by-products of textile factories, cannot be recycled sufficiently. As an attempt to find a solution to this problem, in this study, a by-product of the towel production process, called towel clippings (TC), was used as a source of cellulose for obtaining HPMC. HPMC was synthesized for the first time from the reaction of cellulose, propylene oxide (PO) and chloromethane (CM) under pressure in a gas-tight laboratory scale reactor and then evaluated as an additive in cement paste. The HPMC w . . .as characterized by H-1(C-13)-NMR, FT-IR, XRD, DTA/TGA and SEM techniques. Additionally, the DS values were determined using the C-13-NMR technique. The highest viscosity was obtained as 2740 cP in HPMC-5 with the highest DS value of 2.86. While the setting time of the standard cement paste, without any additives, started at the 140th minute and was completed at the 250th minute, with the addition of 0.5 grams of HPMC-1 to the cement paste, the starting time was extended by 180 minutes and the finishing time was extended by 260 minutes. In this way, it has been seen that problems such as low slip resistance and low setting time of cement paste, as well as negative effects caused by working conditions, will be avoided More less