Biopolymer-Based Materials from Polysaccharides: Properties, Processing, Characterization and Sorption Applications

Biopolymers are polymeric materials derived from biological sources. Due to their renewability, abundance, biodegradability and other unique properties such as high adsorption capabilities and ease of functionalization they have been investigated for several industrial applications including sorption. Polysaccharides especially cellulose, chitin and chitosan are important biopolymers because of their high abundance, wide distribution and low cost of production. This chapter provides an overview of properties, common processing methods, and material characterization of three commonly studied biopolymers namely cellulose, chitin and chitosan. It provides a thorough review on recent developments on utilization of cellulose, chitin, and chitosan-based materials for various sorption applications. Specifically, their application and efficiency in organic dye removal, heavy metals removal, oil and solvent spillage cleanup, and CO2 adsorption are presented and discussed

Association of Spermatogenic Failure with the b2/b3 Partial AZFc Deletion

Infertility affects around 1 in 10 men and in most cases the cause is unknown. The Y chromosome plays an important role in spermatogenesis and specific deletions of this chromosome, the AZF deletions, are associated with spermatogenic failure. Recently partial AZF deletions have been described but their association with spermatogenic failure is unclear. Here we screened a total of 339 men with idiopathic spermatogenic failure, and 256 normozoospermic ancestry-matched men for chromosome microdeletions including AZFa, AZFb, AZFc, and the AZFc partial deletions (gr/gr, b1/b3 and b2/b3)

Association of the MTHFR A1298C Variant with Unexplained Severe Male Infertility

The methylenetetrahydrofolate reductase (MTHFR) gene is one of the main regulatory enzymes involved in folate metabolism, DNA synthesis and remethylation reactions. The influence of MTHFR variants on male infertility is not completely understood. The objective of this study was to analyze the distribution of the MTHFR C677T and A1298C variants using PCR-Restriction Fragment Length Polymorphism (RFLP) in a case group consisting of 344 men with unexplained reduced sperm counts compared to 617 ancestry-matched fertile or normozoospermic controls. The Chi square test was used to analyze the genotype distributions of MTHFR polymorphisms. Our data indicated a lack of association of the C677T variant with infertility. However, the homozygous (C/C) A1298C polymorphism of the MTHFR gene was present at a statistically high significance in severe oligozoospermia group compared with controls (OR = 3.372, 95% confidence interval CI = 1.27–8.238; p = 0.01431). The genotype distribution of the A1298C variants showed significant deviation from the expected Hardy-Weinberg equilibrium, suggesting that purifying selection may be acting on the 1298CC genotype. Further studies are necessary to determine the influence of the environment, especially the consumption of diet folate on sperm counts of men with different MTHFR variants

TEXTILE TECHNOLOGY Processing Sticky Cotton: Implication of Trehalulose in Residue Build-up

In spinning mills, sticky cotton can cause serious problems. It contaminates the textile equipment: opening line, card, drawing, roving, and spinning frames. These contaminants are mainly sugar deposits produced either by the cotton plant itself (physiological sugars) or by feeding insects (entomological sugars), the latter being the most common source of stickiness. Seventeen mixes having a moderate level of stickiness were evaluated in both ring and rotor spinning. High-performance liquid chromatography tests were performed on residues collected from the textile machinery to identify the types of sugars present. It was shown that among the sugars identified on raw fiber, only trehalulose exhibits higher percentages in the residues than on the fiber. During the fibers-to-yarn transformation, the flow of lint is submitted to different friction forces; consequently, the temperature of some mechanical elements may increase significantly and affect the thermal properties of the contaminated lint. After a sugar becomes sticky, the other sugars present on the lint, as well as other substances such as dusts, silica, etc., will stick to the lint and could cause unevenness in the flow of lint being drawn, such as lapping up on the rolls, nep-like structures, and ends-down. Therefore, the thermal properties of the five sugars identified on the contaminated fiber and on the residues collected on the textile equipment were investigated. Among the sugars tested, trehalulose is the only one having a low melting point, around 48(C. In addition, trehalulose is highly hygroscopic. After passive conditioning of dehydrated trehalulose at 65% ± 2% relative humidity and 21(C ± 1(C for 24 h, the quantity of adsorbed water at equilibrium was found to be approximately 17.5%. This corresponds to three molecules of water adsorbed for each molecule of trehalulose. The combination of low melting point and high hygroscopicity could be the cause of the selective accumulation of this sugar on the textile equipment. ABSTRACT Cottons (Gossypium hirsutum L.) contaminated with stickiness can cause multiple problems in the textile mills. Contaminants originate from physiological sugars coming from the plant itself and/or entomological sugars coming from phloemfeeding insects, specifically the cotton aphid [Aphis gossypii (Glover)] and cotton whitefly [Bemisia tabaci (Gennadius)]. During yarn manufacturing, all textile equipment is contaminated with sugar deposits to different degrees, affecting both productivity and yarn quality. We evaluated 17 mixes of moderate stickiness in both ring and rotor spinning. To identify the types of sugars in the sticky deposits collected from the textile machinery, we assayed with highperformance liquid chromatography. Trehalulose (C 12 H 22 O 11 ) was the dominant sugar in these deposits. It has the lowest melting point, 1 1 1 148( ( ( (C, of the sugars involved in cotton stickiness. Dehydrated trehalulose is highly hygroscopic and absorbs 1 1 1 117.5% of water at 65% ± 2% relative humidity and 21( ( ( (C ± 1( ( ( (C. The combination of a low melting point and high hygroscopicity leads to higher concentrations of trehalulose in the residues than on the original fibers

Chemical functionalisation of cotton fabric to impart multifunctional properties

A cotton fabric was functionalised using the nanoparticle vapor deposition (NVD) and molecular vapor deposition (MVD) techniques to impart super hydrophobic/oleophobic properties. The NVD method was used to deposit a layer of Al2O3 nanoparticles onto the fabric surface. MVD led to the deposition of a functional layer of (tridecafl uoro-1,1,2,2,-tetrahydrooctyl)trichlorosilane (FOTS). The nanoparticles deposition increased the surface roughness, leading to higher contact angles when compared with the surfaces functionalised only with FOTS. FTIR spectra showed the presence of peaks corresponding to fluorocarbon chains and Al2O3on functionalised samples. Surface free energies of the samples were calculated. Low hysteresis and dynamic contact angles higher than 150° were obtained for water and organic liquids. Tetrabutyl orthotitanate (Ti(OC4H9)4) was used to functionalise fabrics to impart self-cleaning and UV protection properties. Furthermore, the functionalisation with monochlorotriazyl-β-cyclodextrin molecules introduced cavities on the fabric surface, which were used to perform the inclusion of antimicrobial agents

Cellulose Dissolution in Ionic Liquid under Mild Conditions: Effect of Hydrolysis and Temperature

This study investigated the effect of acid hydrolysis of cellulose on its dissolution under mild conditions in ionic liquid, 1-butyl-3-methylimidazolium acetate/N,N-dimethylacetamide (BMIMAc/DMAc). Acid hydrolysis of high molecular weight (MW) cotton cellulose (DP > 4000) was carried out to produce hydrolyzed cotton (HC) samples for dissolution. The HC samples were characterized using gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), and the dissolution process was monitored using polarized light microscopy (PLM). It was found that the drastic decrease of the MW of cellulose did not result in improvement of its dissolution at room temperature. As compared to original cotton cellulose, the high amount of undissolved fibers in HC solutions led to unstable rheological behavior of HC solutions. Agglomeration and inhomogeneous dispersion of HC, and increased crystallinity, in this case, likely made the diffusion of BMIMAc/DMAc more difficult to the inside of the polymeric network of cellulose at ambient temperature, thereby hindering the dissolution. However, increasing the temperature from room temperature to 35 °C and 55 °C, led to a significant improvement in cellulose dissolution. This phenomenon implies that reducing the MW of cellulose might not be able to improve its dissolution under certain conditions. During the dissolution process, the physical properties of cellulose including fiber aggregation status, solvent diffusivity, and cellulose crystallinity may play a critical role compared to the MW, while the MW may not be an important factor. This finding may help further understand the mechanism of cellulose dissolution and seek better strategies to dissolve cellulose under mild conditions for industrial applications

Characterization of Developing Cotton Fibers by Confocal Raman Microscopy

Cellulose deposition in developing cotton fibers has been studied previously with analytical techniques, such as Fourier transform infrared spectroscopy (FTIR), High-performance liquid chromatography (HPLC) and Thermogravimetric analysis (TGA). Recent technological developments in instrumentation have made Raman microscopy emerge as an extraordinary analytical tool in biological and plant research. The advantage of using confocal Raman microscopy (CRM) resides in the lateral spatial resolution and in the fact that Raman spectroscopy provides not only chemical composition information, but also structural information. Cross-sections of cotton fibers harvested at different developmental stages were studied with CRM. The Raman bands assigned to cellulose were analyzed. The results of this study indicate that CRM can be used as a tool to study cellulose deposition in cotton fibers and could provide useful information on cellulose deposition during cotton fiber development

Borax-cross-linked guar gum-manganese dioxide composites for oxidative decolorization of methylene blue

© 2019 Rohan S. Dassanayake et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Borax-cross-linked guar gum-manganese dioxide (GGB-MnO2) composite was synthesized using an environmentally friendly synthesis route and investigated for its efficiency of decolorizing methylene blue (MB) dye solution by an ultraviolet-visible (UV-Vis) spectrophotometric study. The GGB-MnO2 composite was characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The composite (1.2 g/L) exhibited excellent oxidative decolorization of MB (30 mg/L, 50 mL) solution to over 99% in 6, 13, and 40 min at pH 4, 7, and 10, respectively. The complete decolorization of MB occurred via a catalytic adsorption-oxidation-desorption mechanism. The GGB-MnO2 composite showed very good reusability and was stable after ten successive cycles with negligible losses of the decolorization efficiency