Flexible Biocomposites with Enhanced Interfacial Compatibility Based on Keratin Fibers and Sulfur-Containing Poly(urea-urethane)s

Feathers are made of keratin, a fibrous protein with high content of disulfide-crosslinks and hydrogen-bonds. Feathers have been mainly used as reinforcing fiber in the preparation of biocomposites with a wide variety of polymers, also poly(urea-urethane)s. Surface compatibility between the keratin fiber and the matrix is crucial for having homogenous, high quality composites with superior mechanical properties. Poly(urea-urethane) type polymers are convenient for this purpose due to the presence of polar functionalities capable of forming hydrogen-bonds with keratin. Here, we demonstrate that the interfacial compatibility can be further enhanced by incorporating sulfur moieties in the polymer backbone that lead to new fiber-matrix interactions. We comparatively studied two analogous thermoplastic poly(urea-urethane) elastomers prepared starting from the same isocyanate-functionalized polyurethane prepolymer and two aromatic diamine chain extenders, bis(4-aminophenyl) disulfide (TPUU-SS) and the sulfur-free counterpart bis(4-aminophenyl) methane (TPUU). Then, biocomposites with high feather loadings (40, 50, 60 and 75 wt %) were prepared in a torque rheometer and hot-compressed into flexible sheets. Mechanical characterization showed that TPUU-SS based materials underwent higher improvement in mechanical properties than biocomposites made of the reference TPUU (up to 7.5-fold higher tensile strength compared to neat polymer versus 2.3-fold). Field Emission Scanning Electron Microscope (FESEM) images also provided evidence that fibers were completely embedded in the TPUU-SS matrix. Additionally, density, thermal stability, and water absorption of the biocomposites were thoroughly characterized.This work was supported by KaRMA2020 project. This project has received funding from the European Union’s Horizon 2020 Research and Innovation program under Grant Agreement n 723268

Fully Biodegradable Biocomposites with High Chicken Feather Content

The aim of this work was to develop new biodegradable polymeric materials with high loadings of chicken feather (CF). In this study, the effect of CF concentration and the type of biodegradable matrix on the physical, mechanical and thermal properties of the biocomposites was investigated. The selected biopolymers were polylactic acid (PLA), polybutyrate adipate terephthalate (PBAT) and a PLA/thermoplastic copolyester blend. The studied biocomposites were manufactured with a torque rheometer having a CF content of 50 and 60 wt %. Due to the low tensile strength of CFs, the resulting materials were penalized in terms of mechanical properties. However, high-loading CF biocomposites resulted in lightweight and thermal-insulating materials when compared with neat bioplastics. Additionally, the adhesion between CFs and the PLA matrix was also investigated and a significant improvement of the wettability of the feathers was obtained with the alkali treatment of the CFs and the addition of a plasticizer like polyethylene glycol (PEG). Considering all the properties, these 100% fully biodegradable biocomposites could be adequate for panel components, flooring or building materials as an alternative to wood–plastic composites, contributing to the valorisation of chicken feather waste as a renewable material.This work was supported by KaRMA2020 project. This project has received funding from the European Union’s Horizon 2020 Research and Innovation program under Grant Agreement n° 723268

Build-To-Specification Vanillin and Phloroglucinol Derived Biobased Epoxy-Amine Vitrimers

Epoxy resins are widely used in the composite industry due to their dimensional stability, chemical resistance, and thermo-mechanical properties. However, these thermoset resins have important drawbacks. (i) The vast majority of epoxy matrices are based on non-renewable fossil-derived materials, and (ii) the highly cross-linked molecular architecture hinders their reprocessing, repairing, and recycling. In this paper, those two aspects are addressed by combining novel biobased epoxy monomers derived from renewable resources and dynamic crosslinks. Vanillin (lignin) and phloroglucinol (sugar bioconversion) precursors have been used to develop bi- and tri-functional epoxy monomers, diglycidyl ether of vanillyl alcohol (DGEVA) and phloroglucinol triepoxy (PHTE) respectively. Additionally, reversible covalent bonds have been incorporated in the network by using an aromatic disulfide-based diamine hardener. Four epoxy matrices with di erent ratios of epoxy monomers (DGEVA/PHTE wt%: 100/0, 60/40, 40/60, and 0/100) were developed and fully characterized in terms of thermal and mechanical properties. We demonstrate that their performances are comparable to those of commonly used fossil fuel-based epoxy thermosets with additional advanced reprocessing functionalities.This project has received funding from the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation program under grant agreement No 74431

Functionalization of Cellulose Nanocrystals in Choline Lactate Ionic Liquid

Cellulose nanocrystals (CNCs) are valuable nanomaterials obtained from renewable resources. Their properties make them suitable for a wide range of applications, including polymer reinforcement. However, due to their highly hydrophilic character, it is necessary to modify their surface with non-polar functional groups before their incorporation into a hydrophobic polymer matrix. In this work, cellulose nanocrystals were modified using a silane coupling agent and choline lactate, an ionic liquid derived from renewable resources, as a reaction medium. Modified cellulose nanocrystals were characterized by infrared spectroscopy, showing new peaks associated to the modification performed. X-ray diffraction was used to analyze the crystalline structure of functionalized cellulose nanocrystals and to optimize the amount of silane for functionalization. Poly(lactic acid) (PLA) nanocomposites containing 1 wt % of functionalized cellulose nanocrystals were prepared. They were characterized by field-emission scanning electron microscopy (FE-SEM) and mechanical tests. The use of choline lactate as reaction media has been shown to be an alternative method for the dispersion and silanization of the cellulose nanocrystals without the addition of an external catalyst.Financial support from the European Commission (FP7 Program, ECLIPSE project FP7-NMP-280786) is gratefully acknowledged

Novel CO2 capture membranes based on polymerized ionic liquids and polymeric porous supports

Highly CO2 selective membranes and innovative process designs for CO2 capture can compete with absorption due to relatively low energy consumption and small foot print. In this paper, novel materials poly(ionic liquids) (PILs) are combined with membrane separation for CO2 capture. Poly(ionic liquid)s are solid polymers derived from ionic liquids (ILs) that share many of their physical and chemical properties. For a variety of ILs and PILs, the CO2 sorption is significantly higher than either CH4 or N2 due to Lewis acid-base interactions between the CO2 and nitrogen-containing groups [1]. Our research is focused on developing composite thin film membranes (TFC) of PILs on porous polymeric supports and characterization of these. The membranes are produced and tested by SINTEF, Norway, using the PILs developed by IK4-CIDETEC, Spain, and Solvionic, France. Various families of PILs were synthesized: poly(diallyldimethylammonium) with a hydrophilic acetate anion, poly(vinylbenzylchloride) derived PILs having lithium bis (trifluoromethanesulfonyl) imide as anion or formulations containing a PIL, an ionic liquid and Zn+2 additives. Commercially available porous supports such as polysulfone (PSf) and fluoro polymers with different porosities and pore sizes are screened in the membrane fabrication. A novel coating procedure utilizing automated ultrasonic spray coating equipment is optimized for each pair of dense, CO2 selective layer (PIL) – porous polymeric support material by using different solvents, viscosities of solution and drying protocols. We obtained defect free coatings of 0.4 to 10 micron thickness. Variations in thickness were observed due to pore penetration. The prepared membranes are characterized by contact angle measurements, scanning electron microscopy (SEM) and mixed gas permeation (synthetic flue gas: 15% CO2 in N2-water vapors) using a state of the art gas permeation rig designed and constructed at SINTEF. The effect of gas relative humidity, feed pressure and operating temperature on membrane separation performances is investigated and will be reported. The gas permeation results indicate that the choice of support has significant influence on the CO2 permeance/permeability, while the selectivity remained unchanged. The selectivity is hence, mainly controlled by the properties of CO2 selective PILs top layer and not by the supports. References 1) Melinda L. Jue, Ryan P. Lively, Review -Targeted gas separations through polymer membrane functionalization, Reactive & Functional Polymers 86 (2015) 88–110

Influence of ionic liquid-like cationic pendants composition in cellulose based polyelectrolytes on membrane-based CO2 separation

Cellulose acetate (CA) is an attractive membrane polymer for CO2 capture market. However, its low CO2 permeability hampers its application as part of a membrane for most relevant types of CO2 containing feeds. This work investigates the enhancement of CA separation performance by incorporating ionic liquid-like pendants (1-methylimidazol, 1-methylpyrrolidine, and 2-hydroxyethyldimethylamine (HEDMA) on the CA backbone. These CA-based polyelectrolytes (PEs), synthesised by covalent grafting of cationic pendants with anion metathesis, were characterised by NMR, FTIR, DSC/TGA, and processed into thin-film composite membranes. The membrane performance in CO2/N2 mixed-gas permeation experiments shows a decrease in CO2 and N2 permeability and an initial decrease and then gradual increase in CO2/N2 selectivity with increasing HEDMA content. The amount of HEDMA attached to the CA backbone determines overall separation process in bifunctional PEs. This indicates that the hydroxy-substituted cationic pendants alter interactions between PEs network and permeating CO2 molecules, suggesting possibilities for further improvements

Supporting Information for “Click” synthesis of nonsymmetrical bis(1,2,3-triazoles)

Preparation procedures, physical and spectroscopic data for compounds 4a−m, 5a−h, 6h,n, 8a−f, 11, and 12.Peer reviewe

“Click” synthesis of nonsymmetrical bis(1,2,3-triazoles)

Unsymmetrically 1,1′-disubstituted 4,4′-bis-1H-1,2,3-triazoles 4 have been prepared from 4-ethynyl-1,2,3-triazoles 5 and azides. Following a “double-click” strategy, two complementary approaches were implemented for the preparation of the key 4-ethynyltriazole intermediates 5: (a) the stepwise Swern oxidation/Ohira−Bestman alkynylation of readily available 4-hydroxymethyl-1,2,3-triazoles 8 and (b) the stepwise cycloaddition of TMS-1,4-butadiyne 9. The method is highlighted by its compatibility with orthogonally protected and functionalized saccharide−peptide hybrids and its ability to be extended to the trisubstituted counterparts 12.We thank the Ministerio de Educación y Ciencia (MEC, Spain) (Project No. CTQ2006-13891/BQU), UPV/EHU, and Gobierno Vasco (ETORTEK-inanoGUNE IE-08/225) for financial support and SGIker UPV/EHU for NMR facilities. Predoctoral grants from Gobierno Vasco to I.A. and M.S.-A. are acknowledged.Peer reviewe

Aero Grade Epoxy Vitrimer towards Commercialization

Traditional crosslinked aero grade epoxy resins have excellent thermal-mechanical properties and solvent resistance, but they cannot be remolded, recycled, or repaired. Vitrimers can be topologically rearranged via an associative exchange mechanism, endowing them with thermoplasticity. Introducing dynamic bonds into crosslinked networks to obtain more sustainable thermosets is currently an interesting research topic. While recent research into vitrimers has indicated many advantages over traditional thermosets, an important shortcoming has been identified: susceptibility to creep at service temperature due to the dynamic bonds present in the network. In addition, designing aero grade epoxy vitrimers (similar to RTM6 resin) still remains a challenge. Herein, low creep aero grade epoxy vitrimer with thermal and mechanical properties similar to those of aero grade epoxy resins and with the ability to be recyclable, repairable, and reprocessable, has been prepared. In this manuscript, we demonstrate that aero grade epoxy vitrimer with reduced creep can be easily designed by the introduction of a certain fraction of permanent crosslinks, without having a negative effect on the stress relaxation of the material. Subsequently, the mechanical and relaxation properties were investigated and compared with those of classical aero grade epoxy resin. A high Tg (175 C) epoxy vitrimer was obtained which fulfilled all mechanical and thermal specifications of the aero sector. This work provides a simple network design to obtain aero grade epoxy resins with excellent creep resistance at elevated temperatures while being sustainable.This research has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 769274, “AIRPOXY”