In the present paper, a scalable, economically feasible, and continuous process for making cellulose-based carbon fibers (CFs) is described encompassing precursor spinning, precursor additivation, thermal stabilization, and carbonization. By the use of boric acid (BA) as an additive, the main drawback of cellulose-based CFs, i.e.
View Article and Find Full Text PDFThe still-rising global demand for plastics warrants the substitution of non-renewable mineral oil-based resources with natural products as a decisive step towards sustainability. Lignin is one of the most abundant natural polymers and represents an ideal but hitherto highly underutilized raw material to replace petroleum-based resources. In particular, the use of lignin composites, especially polyolefin-lignin blends, is currently on the rise.
View Article and Find Full Text PDFCarbohydr Polym
January 2021
The direct dissolution and joint spinning of cellulose and lignin from NMMO-water were investigated by using dissolving pulp and purified KRAFT lignin. Compared to the rather narrow dissolution window of cellulose in the NMMO-water system, lignin with concentrations up to 15 wt.-% was shown to dissolve in a range from 30 % NMMO to 70 % NMMO at room temperature.
View Article and Find Full Text PDFPresented study deals with the pre-treatment of cellulose fibres with the aim to activate their surface and to enlarge their pore system, leading to an enhancement of fibres' affinity for subsequent functionalization processes. Swelling of fibres in aqueous solutions of sodium hydroxide opens their fibrillar structure, while freezing and freeze-drying retain this enlargement of the pore system, in contrast with conventional air or elevated temperature drying. Effect of different pre-treatment procedures on fibres' supramolecular structure, enlargement of their pore system, surface topography, zeta potential and mechanical properties was investigated.
View Article and Find Full Text PDFTo investigate the effects of an ethologically-relevant stressor on central and peripheral release of arginine vasopressin and oxytocin, we forced adult male Wistar rats to swim for 10 min and simultaneously measured the release of the two peptides (i) within the hypothalamic supraoptic and paraventricular nuclei (by means of the microdialysis technique) and (ii) into the blood (by chronically-implanted jugular venous catheters). Forced swimming caused a significant rise in the release of arginine vasopressin and oxytocin within both the supraoptic nuclei (four-fold and three-fold, respectively) and the paraventricular nuclei (three-fold and four- to five-fold, respectively). Release patterns measured before, during and after repeated stress exposure on three consecutive days indicated that, at the level of the hypothalamus, the two neuropeptides are critically involved in the rats' stress response in a peptide-, locus- and stress-specific manner.
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