Morphology, composition and structure of the fibers of a Chimu culture textile

In this work we studied the microfibers of a textile (T-shirt) of the Chimú culture. This culture developed on the northern coast of Peru. To determine the raw material and structural quality of the microfibers, the results of the Chimú textile were compared with the corresponding results for the microfibers of cotton from the northern coast of Peru (native cotton). Scanning electron microscopy images revealed that the Chimú textile yarns are composed of a set of interwoven microfibers. Energy dispersive X-ray spectroscopy and pulsed laser-induced plasma spectroscopy techniques allowed the identification of characteristic cellulose atoms in the microfibers of Chimú textile and native cotton. Only for the Chimú textile, these spectroscopic techniques allowed the identification of atoms corresponding to natural dyes and powder residues. Attenuated total reflection Fourier transform infrared spectroscopy identified the same molecular bonds for the microfibers of Chimú textile and native cotton. For the microfibers of Chimú textile and native cotton, the X-ray diffractograms showed peaks characteristic of the cellulose Iβ polymorphism of of monoclinic P21 structure. The raw material of the Chimú textile is cotton and the microfibers of this material show significant structural stability.

Generation of highly amenable cellulose-Iβ via selective delignification of rice straw using a reusable cyclic ether-assisted deep eutectic solvent system

Cellulolytic enzymes can readily access the cellulosic component of lignocellulosic biomass after the removal of lignin during biomass pretreatment. The enzymatic hydrolysis of cellulose is necessary for generating monomeric sugars, which are then fermented into ethanol. In our study, a combination of a deep eutectic (DE) mixture (of 2-aminoethanol and tetra-n-butyl ammonium bromide) and a cyclic ether (tetrahydrofuran) was used for selective delignification of rice straw (RS) under mild conditions (100 °C). Pretreatment with DE-THF solvent system caused ~ 46% delignification whereas cellulose (~ 91%) and hemicellulose (~ 67%) recoveries remained higher. The new solvent system could be reused upto 10 subsequent cycles with the same effectivity. Interestingly, the DE-THF pretreated cellulose showed remarkable enzymatic hydrolysability, despite an increase in its crystallinity to 72.3%. Contrary to conventional pretreatments, we report for the first time that the enzymatic hydrolysis of pretreated cellulose is enhanced by the removal of lignin during DE-THF pretreatment, notwithstanding an increase in its crystallinity. The current study paves way for the development of newer strategies for biomass depolymerization with DES based solvents.

Cellulose Nanocrystals Derived from Textile Waste through Acid Hydrolysis and Oxidation as Reinforcing Agent of Soy Protein Film

More than 10 million tons of textile waste are disposed through landfill every year in North America. The disposal of textile waste via landfill or incineration causes environmental problems and represents a waste of useful resources. In this work, we explored the possibility to directly extract cellulose nanocrystals (CNCs) from untreated textile waste through two methods, namely sulfuric acid hydrolysis and three-step oxidization. CNCs with cellulose Iβ crystalline structure and rod-like shape were successfully obtained. The aspect ratios of CNCs prepared from acid hydrolysis and oxidization were 10.00 ± 3.39 and 17.10 ± 12.85, respectively. Their application as reinforcing agent of soybean protein isolate (SPI) film was evaluated. With the addition of 20% CNCs, the composite film maintained the high transparency, while their water vapor barrier property, tensile strength, and Young’s modulus were significantly improved. This research demonstrates a promising approach to recycle textile waste, and more value-added applications based on the derived CNCs could be expected.

Thermal Response in Cellulose Iβ Based on Molecular Dynamics

The structural details of cellulose I β were discussed according to molecular dynamics simulations with the GLYCAM-06 force field. The simulation outcomes were in agreement with previous experimental data, including structural parameters and hydrogen bond pattern at 298 K. We found a new conformation of cellulose Iβ existed at the intermediate temperature that is between the low and high temperatures. Partial chain rotations along the backbone direction were found and conformations of hydroxymethyl groups that alternated from tg to either gt or gg were observed when the temperature increased from 298 K to 400 K. In addition, the gg conformation is preferred than gt. For the structure adopted at high temperature of 500 K, major chains were twisted and two chains detached from each plain. In contrast to the observation under intermediate temperature, the population of hydroxymethyl groups in gt exceeded that in gg conformation at high temperature. In addition, three patterns of hydrogen bonding were identified at low, intermediate and high temperatures in the simulations. The provided structural information indicated the transitions occurred around 350 K and 450 K, considered as the transitional temperatures of cellulose Iβ in this work.

ANALYSIS OF STRUCTURAL CHANGES OF CELLULOSE COMPONENT IN PROCESS OF ELEMENTARIZATION OF FLAX FIBERS

The comparative research of composition and supramolecular structure of the flax fibers received by methods of a cottonization and a mechanical elementarization under the influence of the cyclic deforming loadings was conducted. It was shown that under the influence of cyclic loadings removal of a considerable part of impurity with the increase in content of cellulose to 80.1% is reached. At the same time, division of complexes onto elementary filament provides the increase in the total surface of material and, as a result, to availability of fibers to the reagents at the subsequent alkaline boiling. X-ray analysis of flax samples with a method of comparison of the normalized parameters of diffraction by crystalline regions of cellulose allowed to establish that degree of crystallinity of a cellulose component of fibers remains constant even at deep purification of raw materials under the influence of cyclic deformations and subsequent boiling. The research of the oriented fibers by X-ray diffraction method has shown that removal of impurity from flax in the course of an elementarization has only weak influence on the sizes of crystallites of cellulose. The increase in the cross sizes of crystallites by 4 – 6% was observed at deep purification of fibers due to the boiling. This phenomenon can be connected with the decrease in influence of a diffraction maximum from impurity on half-width of the equatorial reflex 200 for cellulose Iβ. It should be noted that the longitudinal sizes of crystallites at the same time do not change. It was suggested on possible influence of decrease in content of impurity on supramolecular structure of an amorphous phase of cellulose and as a result on the observed growth of sorption and mechanical properties of flax fibers at an elementarization by method of cyclic deformation.Forcitation:Zavadskii A.E., Stokozenko V.G., Moryganov A.P., Larin I.Yu. Analysis of structural changes of cellulose component in process of elementarization of flax fibers. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 6. P. 102-108.