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ABSTRACT: Porous carbon materials represent prospective materials for absorbers, filters, and electronic applications. Carbon fibers with high surface areas can be produced from polyacrylonitrile and spun as thin fibers from solution. The resulting polymer fibers are first stabilized to obtain conjugated ribbons and then carbonized to graphitic structures in a second high‐temperature step in an inert atmosphere. In this study, we investigated a previously described fast laser‐heating process that delivered fibers with a higher crystallinity and surface area compared to the thermally carbonized fibers. In a subsequent KOH‐activation step, the crystalline domains were exfoliated, and the surface of the fibers became macroporous. This led to a reduced specific surface area but a higher capacitance compared to thermally carbonized nanofibers. We report the electrochemical properties of the electrochemical cells and discuss their potential applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46398. [ABSTRACT FROM AUTHOR]

As a widely applied polymer, hydrophilic modification of polypropylene (PP) has been an important research field. Forcespinning™ uses centrifugal force to fabricate nanofibers rather than electrostatic force as in conventional electrospinning. The absence of electric fields provides a board opportunity for low dielectric materials and the utilization of centrifugal forces significantly increases the yield compared to electrospinning. Hydrophilic nonwovens from isotactic polypropylene (iPP) melt blended with amphihilic surfactant TWEEN20 and TWEEN60 were obtained by Forcespinning™. The factors were investigated by SEM and DSC, which determined fiber diameter distribution and crystallinity. The meshes showed continuous homogeneity along the length of the fiber when the system was employed at 225 °C and the rotational speed at 14,000 rpm. Blending with surfactants bearing ethoxylate groups led to increased oxygen content of the meshes surface as confirmed by ATR-FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). XPS results indicated preferential distribution of additives on surfaces. The forcespun meshes exhibited excellent hygroscopicity even when the load of TWEEN20 was 10 %. [ABSTRACT FROM AUTHOR]

The halogen-free shrinkproofing resin presented in this work is based on the natural protein collagen and a crosslinking agent, which provides a covalent linkage between the wool and the resin (collagen). Glycidylacrylate and the trifunctional epoxide Araldit PT 810 are applied as crosslinkers. Almost complete shrink resistance of wool fabric and top is achieved using the collagen / Araldit resin with plasma pretreated material. In combination with the oxidative plasma treatment described in Part I, the additive collagen treatment appears to be an effective substitute for the chlorine /Hercosett process. [ABSTRACT FROM PUBLISHER]

The glow discharge treatment of wool in nonpolymerizing gases like air, oxygen, and nitrogen is presented as a new zero-AOX pretreatment for shrinkproofing wool top and fabric. Modification of the wool fibers is restricted to the outer 30-50 nm, and consists of plasma etching and surface oxidation. The former is responsible for the abrasion of the fatty acid layer from the cuticle and parts of the exocuticle-A; the latter introduces new anionic groups, i.e., sulphonate and carboxylate functions. Car boxyl groups derive from a backbone oxidation of the protein chains in the cuticle cells. Sulphonate groups are generated by oxidation of disulphide functions. Surface modification applicable to both wool top and fabric results in an increased hydro philicity of the fiber surface and has an excellent shrinkproofing effect in combination with a new shrinkproofing resin. [ABSTRACT FROM PUBLISHER]

Describes case studies of teacher training experiments which provide student teachers with work experience outside the school system during their training, incorporate existing experience or confront teachers with conditions as regards places of work outside the school environment. Teacher training in the Twind schools in Denmark; Teachers involved in the system of educational holiday for workers in Italy.

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Highly loaded polymer/clay nanocomposites with layered structures are emerging as robust fire retardant surface coatings. However, time-intensive sequential deposition processes, e.g. layer-by-layer strategies, hinders obtaining large coating thicknesses and complicates an implementation into existing technologies. Here, we demonstrate a single-step, water-borne approach to prepare thick, self-assembling, hybrid fire barrier coatings of sodium carboxymethyl cellulose (CMC)/montmorillonite (MTM) with well-defined, bioinspired brick-wall nanostructure, and showcase their application on textile. The coating thickness on the textile is tailored using different concentrations of CMC/MTM (1-5 wt%) in the coating bath. While lower concentrations impart conformal coatings of fibers, thicker continuous coatings are obtained on the textile surface from highest concentration. Comprehensive fire barrier and fire retardancy tests elucidate the increasing fire barrier and retardancy properties with increasing coating thickness. The materials are free of halogen and heavy metal atoms, and are sourced from sustainable and partly even renewable building blocks. We further introduce an amphiphobic surface modification on the coating to impart oil and water repellency, as well as self-cleaning features. Hence, our study presents a generic, environmentally friendly, scalable, and one-pot coating approach that can be introduced into existing technologies to prepare bioinspired, thick, fire barrier nanocomposite coatings on diverse surfaces. [ABSTRACT FROM AUTHOR]