Keratin proteins are the major component of hair, feathers, wool and horns and represent an important source of renewable raw materials for many applications. Regenerated keratin has useful properties such as biocompatibility and biodegradability. Moreover, keratin materials can absorb heavy metal ions, formaldehyde and other VOCs. In this work, regenerated keratin was blended with aqueous solutions of poly(ethylene oxide) (PEO) in different proportion in order to improve its processability. Keratin/PEO nanofibres were produced by electrospinning the blend aqueous solutions. The chemical, physical and rheological characteristics of the blend solutions were correlated with morphology, structural, thermal and mechanical properties of the electrospun mats.

Structure and properties of Keratin/PEO blend nanofibres

Handbook Of Thermoplastic Elastomers

Natural fibers are getting attention from researchers and academician for utilization in new technology due to their ecofriendly nature and sustainability. This paper reviews advancements of utiliz...

Advancements in Applications of Natural Wool Fiber: Review

The presented work deals with the creation of a new radial basis function artificial neural network-based model of dynamic thermo-mechanical response and damping behavior of thermoplastic elastomers in the whole temperature interval of their entire lifetime and a wide frequency range of dynamic mechanical loading. The created model is based on experimental results of dynamic mechanical analysis of the widely used thermoplastic polyurethane, which is one of the typical representatives of thermoplastic elastomers. Verification and testing of the well-trained radial basis function neural network for temperature and frequency dependence of dynamic storage modulus, loss modulus, as well as loss tangent prediction showed excellent correspondence between experimental and modeled data, including all relaxation events observed in the polymeric material under study throughout the monitored temperature and frequency interval. The radial basis function artificial neural network has been confirmed to be an exceptionally high-performance artificial intelligence tool of soft computing for the effective predicting of short-term viscoelastic behavior of thermoplastic elastomer systems based on experimental results of dynamic mechanical analysis.

Radial Basis Function Neural Network-Based Modeling of the Dynamic Thermo-Mechanical Response and Damping Behavior of Thermoplastic Elastomer Systems

The selective capture of radioactive cesium, strontium, and lanthanides from liquid nuclear waste is of great significance to environmental remediation and human health. Herein, the rapid and selective removal of Cs+, Sr2+, and Eu3+ ions is achieved by two metal sulfides (FJSM-SnS-2 and FJSM-SnS-3). Both structures feature [Sn3S7]n2n- layers with the mixed cations of [CH3NH3]+ and [Bmmim]+ (1-butyl-2,3-dimethylimidazolium) as templates. However, the ratios and arrangements of mixed cations in the interlayered spaces are distinct. It is unprecedented that [CH3NH3]+ and [Bmmim]+ in FJSM-SnS-2 are alternatingly arranged in different interlayered spaces, whereas they in FJSM-SnS-3 are located in the same interlayered spaces. It is the first time that the ionic liquid cation and protonated organic amine have been simultaneously incorporated into metal sulfides. Both compounds show high capacities, rapid kinetics, and a wide pH active range for Cs+, Sr2+, and Eu3+. Even under excess Na+ ions, both show excellent selectivity in capturing trace Sr2+ and Eu3+ ions. FJSM-SnS-3 presents the highest KdEu to date. They still retain high removal efficiency even after intense β and γ radiation. Moreover, it is first confirmed by the in situ tracking method of mass spectrometry that the large-sized [Bmmim]+ ions are exchangeable. It is found that the arrangement of cations between interlayered spaces is a crucial factor affecting ion exchange performance. This work will likely change the consensus that large-sized organic cations are difficult to be exchanged and thus further highlight the great potential of metal sulfide ion exchangers for radionuclide remediation.

Layered Thiostannates with Distinct Arrangements of Mixed Cations for the Selective Capture of Cs+, Sr2+, and Eu3+ Ions.

The effect of electron beam on sheep wool

Electron beam irradiated sheep wool – Prospective sorbent for heavy metals in wastewater

Wool scoured in tap water with no special degreasing and containing a balanced humidity responding to usual laboratory conditions was irradiated by accelerated electron beam in the range of 0–350 kGy dose. Time variations of the wool structure were measured using FTIR, Raman, and EPR spectroscopy. The aim was to determine whether preexposure treatment of the wool, as well as postexposure time, affects the properties of the irradiated wool. Reactive products such as S-sulfonate, cystine monoxide, cystine dioxide, cysteic acid, disulphides, and carboxylates displayed a considerable fluctuation in quantity depending on both the absorbed dose and time. Mutual transformations of S-oxidized products into cysteic acid appeared to be faster than those in dry and degreased wool assuming that the present humidity inside the fibres is decisive as an oxygen source. EPR results indicated a longer lifetime for free radicals induced by lower doses compared with the radicals generated by higher ones. The pattern of the conformational composition of the secondary structure (α-helix, β-sheet, random, and residual conformations) also showed a large variability depending on absorbed dose as well as postexposure time. The most stable secondary structure was observed in nonirradiated wool but even this showed a small but observable change after a longer time, too.

/pdf/time-dependent-variations-in-structure-of-sheep-wool-4vwsy5j7q5.pdf

Time-Dependent Variations in Structure of Sheep Wool Irradiated by Electron Beam

Electron beam (EB) irradiated wool was examined for sorption of chromic ions. Sorption increased with the adsorbed dose non-monotonously, which is a result of the generation of S-oxidized groups, secondary structure variation, and the breaking of the keratin backbone. For a dose of 400 kGy, an increase by 120 % was observed at the cystine dioxide and cysteine acid amounts. Examining sorption of unexposed wool and that irradiated with doses of 25 kGy and 40 kGy for basic, methylene blue (MB), or acidic, pyrogallol red (PR) dyes revealed that such low doses have no effect on the carboxylic or amino groups of keratin. Sorption of MB is independent of the EB treatment and is identical for both samples due to the interaction of MB amino groups with the carboxylic groups of wool; however, the sorption capacity for PR is a function of the EB treatment. The sample irradiated with the dose of 25 kGy showed higher PR sorption than that with the EB dose of 40 kGy, which was equal to that of unexposed wool. While the 25 kGy sample provided more active sites for PR interaction compared with the unexposed one, the 40 kGy sample contained already enough active sites to generate intra- and intermolecular interactions inside wool. Thus, PR adherence to the 40 kGy sample was restricted and comparable to the level of unexposed wool.

Sorption properties of sheep wool irradiated by accelerated electron beam

Sorption of higher concentrations of Cu(II) solution onto natural sheep wool or wool irradiated by an electron beam was studied. Sorption isotherms were of unexpected character, showing extremes. The samples with lower absorbed doses adsorbed less than non-irradiated wool, while higher doses led to increased sorption varying with both concentration and dose. FTIR spectra taken from the fibre surface and bulk were different. It was concluded that there was formation of Cu(II)-complexes of carboxylic and cysteic acids with ligands coming from various keratin macromolecules. Clusters of chains crosslinked through the ligands on the surface limit diffusion of Cu(II) into the bulk of fibre, thus decreasing the sorption. After exhausting the available ligands on the surface the remaining Cu(II) cations diffuse into the keratin bulk. Here, depending on accessibility of suitable ligands, Cu(II) creates simple or complex salts giving rise to the sorption extremes. Suggestion of a mechanism for this phenomenon is presented.

https://www.mdpi.com/1420-3049/23/12/3180/pdf

Peter Hybler

Papers

The effect of electron beam on sheep wool

Electron beam irradiated sheep wool – Prospective sorbent for heavy metals in wastewater

Time-Dependent Variations in Structure of Sheep Wool Irradiated by Electron Beam

Sorption properties of sheep wool irradiated by accelerated electron beam

Why Natural or Electron Irradiated Sheep Wool Show Anomalous Sorption of Higher Concentrations of Copper(II).