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- ItemPhotocurable Oil-Based Thermosets Containing Modifiers from Renewable Sources for Coating Applications(AMER CHEMICAL SOC, 2024-10-28) Jašek, Vojtěch; Fučík, Jan; Bartoš, Otakar; Figalla, Silvestr; Přikryl, RadekCoating materials involving nature-inspired compounds or renewable sources have recently attracted vast attention. This article presents the synthesis of modified rapeseed oil (MRO) as a precursor possessing high biobased carbon content suitable for cured thermosets formation. Two reactive diluents based on renewable sources, methacrylated methyl 3-hydroxybutyrate (M3HBMMA) and ethyl 3-hydroxybutyrate (E3HBMMA), were successfully synthesized. Lastly, isosorbide monomethacrylate (MISD) was suggested and produced as a polarity modifier miscible with modified curable oil systems capable of increasing the thermoset surface energy. All synthesized compounds were structurally analyzed via NMR, ESI-MS, and FTIR. The characterized reactive substances were coated on paper, stainless steel, and beech wood to investigate their suitability for forming thin layers. The paper dip coating verified the reactive diluting properties of M3HBMMA, resulting in the average formed coating deviation decrease (87.5% for undiluted MRO and 28.0% for 50 wt % M3HBMMA containing MRO). Also, the additional cured thermoset weight decreased from 350 to 69 wt % for the same systems. The standardized bend test applied on the coated stainless steel specimens revealed the thermoset's flexibility and adhesion increase from a 12 +/- 2 degrees bending angle of 100% pure MRO to a 121 +/- 2 degrees bending angle measured for 40 wt % E3HBMMA containing the MRO-based thermoset. The coated beech wood samples underwent the standardized cross-hatch test investigating the substrate's coating quality. The 100% MRO reached a level 1 rating (second worst), while the system with 40 wt % of MISD obtained a level 5 rating (the best).
- ItemCharacterization of hybrid silicate materials based on ceramic glazes and waste London underground dust(Elsevier, 2024-09-25) Ovčačíková, Hana; Miller, Jeffrey Stephen; Matějka, Vlastimil; Bartoníčková, Eva; Jankovský, Ondřej; Vlček, JosefIn "London Underground" stations, a high concentration of dust particles containing organic and inorganic matter of varying chemical composition. "London underground dust" is created from train wheels and brakes grinding against steel tracks and collected in filtration systems. The experiment will focus on using "London Underground Dust" to colour the ceramic facing tiles intended for re-use in newly built London Underground stations. The phase composition, particle size distribution surface area, morphology, and thermal behavior of collected dust were studied by XRD, XRF, SEM-EDS, BET, heating microscopy, STA-MS, UV-VIS spectroscopy. The substrate tiles for glazing experiments were prepared from local London clay. The mixtures of glazes and collected or milled dust were sprayed on the substrate tile's surface, dried and finally fired at 1060 degree celsius. The influence of used materials weight ratio and dust milling time were shown as crucial parameters to obtain optimal final glaze colour.
- ItemPoly(lactide) Upcycling Approach through Transesterification for Stereolithography 3D Printing(AMER CHEMICAL SOC, 2024-10-02) Figalla, Silvestr; Jašek, Vojtěch; Fučík, Jan; Menčík, Přemysl; Přikryl, RadekThe legislature determines the recycled and waste contents in fabrication processes to ensure more sustainable production. PLA's mechanical recycling and reuse are limited due to the performance decrease caused by thermal or hydrolytic instability. Our concept introduces an upcycling route involving PLA depolymerization using propylene glycol as a reactant, followed by the methacrylation, assuring the liquid systems' curability provided by radical polymerization. PLA-containing curable systems were studied from a rheological and thermomechanical viewpoint. The viscosity levels varied from 33 to 3911 mPas at 30 degrees C, giving a wide capability potential. The best system reached 2240 MPa storage modulus, 164.1 degrees C glass-transition temperature, and 145.6 degrees C heat-resistant index, competitive values to commercial systems. The printability was verified for all of the systems. Eventually, our concept led to SLA resin production containing PLA waste content up to 51 wt %.
- ItemChemically recycled commercial polyurethane (PUR) foam using 2-hydroxypropyl ricinoleate as a glycolysis reactant for flexibility-enhanced automotive applications(ROYAL SOC CHEMISTRY, 2024-09-20) Jašek, Vojtěch; Montag, Petr; Menčík, Přemysl; Přikryl, Radek; Kalendová, Alena; Figalla, SilvestrThe automotive industry uses polyurethane (PUR) foam core in the vehicle headliner composite. The sector demands recycling suggestions to reduce its scrap and decrease the expenses. This work investigated the PUR depolymerization using synthesized 2-hydroxypropyl ricinoleate (2-HPR) from castor oil and incorporated the liquid recyclate (REC) into the original PUR foam. The synthesis of 2-HPR yielded 97.5%, and the following PUR depolymerization (via glycolysis) reached 87.2% yield. The synthesized products were verified by GPC, FTIR, ESI-MS, and 1H NMR cross-analysis. The laboratory experiments (565 mL) included rheological, structural, and reactivity investigations. Added 30% REC content decreased the apparent viscosity to 109 mPa s from standard 274 mPa s. The reactivity of the 30% REC system increased by 51.2% based on the cream time due to the high REC amine value. The block foam density of systems with 15% REC and above decreased by 14.8%. A system with 20% REC content was the most prospective for up-scale. The industrially significant up-scale (125 L) was performed successfully, and the tensile and flexural test specimens were sampled from the up-scaled foam. The tensile characteristic (tensile strength 107 +/- 8 kPa and elongation 9.2 +/- 0.7%) and flexural characteristic (flexural strength 156 +/- 12 kPa and flexural strain at deformation limit 23.4 +/- 0.6%) confirmed that the REC incorporation in the standard PUR foam improves the applicable significant mechanical properties and assures the manufacture improve. Chemical recycling is a material and energy-saving concept that solves the landfilling and incinerating of used materials. This article presents the polyurethane chemical recycling route, including a bio-based solvent.
- ItemEpitaxial Guidance of Adamantyl-Substituted Polythiophenes by Self-Assembled Monolayers(AMER CHEMICAL SOC, 2024-09-03) Farka, Dominik; Cigánek, Martin; Veselý, Dominik; Kalina, Lukáš; Krajčovič, JozefThe anisotropic nature of charge transport through organic materials requires high control over the self-assembly of the organic materials. This is particularly so for conductive polymers, where transport occurs mainly along the polymers' backbone. Herein, we demonstrate the use of self-assembled monolayers (SAMs) to influence the self-assembly of poly(3-adamantylmethylthiophene). We employ two different SAMs, which interact with either the adamantyl- or the thiophene-functionality, respectively, and acquire distinct topologies as compared to the unmodified Au(111) surface. We compare these results with unmodified glass and mica (muscovite) surfaces, which are typically employed in the field of optoelectronics. We prove the usefulness and applicability of epitaxial effects and adamantyl substituents for organic electronics. This presents a viable way toward improved electronic performance for the field as a whole.