http://hdl.handle.net/10563/1000004 Tue, 12 May 2026 14:04:13 GMT 2026-05-12T14:04:13Z http://hdl.handle.net/10563/1012818 Early-stage degradation of electrolytic iron particle-based magnetorheological elastomer under natural weathering conditions Viension, Rehnupreya Hentry; Nordin, Nur Azmah; Mazlan, Saiful Amri; Johari, Mohd Aidy Faizal; Wereley, Norman M.; Fatah, Abdul Yasser Abd; Zaini, Nursyafiqah; Sedlačík, Michal Magnetorheological elastomer (MRE) is a smart composite possessing properties that can be tuned by an external magnetic field, making them highly attractive for vibration isolation applications. Their reliable use in outdoor environments, however, requires a clear understanding of how natural weathering influences their performance and durability. While most previous research has addressed long-term or accelerated ageing conditions, the onset of environmental degradation of MRE remains insufficiently explored. Therefore, this study investigated the early-stage degradation of MRE, embedded with irregular electrolytic iron particles (MRE-EIP) over six weeks of natural weathering exposure. Weekly samples (W0-W6) were analysed using vibrating sample magnetometer (VSM), rheometer and low vacuum scanning electron microscope and the results were correlated with weathering data from the Malaysian Meteorological Department, Kuala Lumpur. The saturation magnetization, Ms finding shows minimal change from 111.63 Am2/kg in W0 to 113.79 Am2/kg in W6, likely attributed to the exposure of EIP following the removal of the aged localized surface over the six week exposure. Strain sweep results meanwhile, revealed the progressive stiffening, with the storage modulus (G′) increased from 0.22 MPa (W0) to 0.53 MPa (W6), accompanied by a narrowing linear viscoelastic (LVE) region, indicative of early embrittlement of the samples. Nevertheless, a temporary reduction in G′ for W3 suggested a moisture-induced plasticisation, from increased rainfalls that week. Besides, the absolute MR effect, ΔG′ increased from 0.23 MPa (W0) to 0.34 MPa (W6), indicating greater responsiveness of exposed EIP to the magnetic fields which enhanced the G′ accordingly. Morphological analysis confirmed the development of localized surface depressions suggests combine effects of UV-driven embrittlement and moisture plasticisation from rainfall, leading to localised EIP exposure, while the cross-sectional structure integrity remained intact. These findings provide the first detailed account of early-stage degradation in MRE-EIP under natural weathering, offering valuable insights into early failure mechanisms and guiding durability driven material design for outdoor smart material applications. Thu, 01 Jan 2026 00:00:00 GMT http://hdl.handle.net/10563/1012818 2026-01-01T00:00:00Z http://hdl.handle.net/10563/1012826 The Influence Of Polyphosphate Mixture On The Growth Of Bacteria Significant In The Food Industry Buňková, Leona; Jaššo, Miroslav; Kuchař, Dalibor; Buňka, František Phosphates are frequently used in the food processing, especially in the dairy and meat industries. They act as emulsifying salts, crucial in the manufacturing of processed cheeses. The effect of Cremosal AB4, a commercially used polyphosphate mixture, was tested in vitro on the growth of nine bacterial strains significant in the food industry: Staphylococcus, Bacillus, Geobacillus, Clostridium, Enterococcus, Lactococcus, Lactobacillus, and Escherichia. Five phosphate concentrations (0.1, 0.2, 0.3, 0.4, and 0.5% w/v, calculated on P2O5) were selected to assess the effect of the polyphosphate mixture on bacterial growth. The susceptibility of each bacterial strain to Cremosal AB4 phosphate was evaluated in a liquid culture medium enriched with the appropriate salt concentration. Subsequently, cell growth was assessed by measuring optical density at 850 nm. The results indicate that even at the lowest tested concentration of 0.1% w/v, Cremosal AB4 polyphosphate effectively inhibited the growth of all bacteria examined, except Lactococcus lactis subsp. lactis CCDM 141 and Escherichia coli CCM 3954. Thu, 01 Jan 2026 00:00:00 GMT http://hdl.handle.net/10563/1012826 2026-01-01T00:00:00Z http://hdl.handle.net/10563/1012812 Closed-loop recycling of automotive semi-rigid polyurethane foam using renewable coconut oil Montág, Petr; Gotkiewicz, Olga; Jašek, Vašek; Figalla, Silvestr; Kalendová, Alena; Beneš, Hynek The automotive sector represents one of the major application fields for polyurethane (PUR) materials, but their end-of-life management still remains a significant sustainability challenge. This study presents a closed-loop recycling approach for semi-rigid PUR foams employed as interior acoustic insulation in automotive headliners. A bio-based transesterified coconut oil was utilized as a sustainable solvolysis reagent to depolymerize automotive PUR waste and recover recycled polyol. The regenerated recycled polyol exhibited suitable hydroxyl value and viscosity, allowing direct substitution of up to 40 wt% of standard polyol in industrial formulations of semi-rigid PUR foam. The PUR foam with incorporated recycled polyol exhibited good structural integrity, sufficient stiffness due to the presence of aromatic structures, along with balanced flexibility derived from glyceride chain segments, thereby avoiding brittleness. The laboratory-scale formulation was successfully scaled up for the production of an industrial headliner demonstrator, confirming the practical feasibility of recycled polyol use in real manufacturing conditions. This work highlights a circular and sustainable strategy for PUR-based automotive components, reducing dependence on petrochemical feedstocks and mitigating environmental impacts. Thu, 01 Jan 2026 00:00:00 GMT http://hdl.handle.net/10563/1012812 2026-01-01T00:00:00Z http://hdl.handle.net/10563/1012811 Dark chocolates: Effects of emulsifier types and concentrations on physico-mechanical properties Lapčíková, Barbora; Lapčík, Lubomír; Neuwirth, Vojtěch; Okelo, Erick Omodho; Valenta, Tomáš; Vašina, Martin; Řepka, David; Machalová, Aneta This study investigated the effects of post-conching blending with various emulsifiers on the physico-mechanical and sensory properties of dark chocolate. Polyglycerol polyricinoleate (PGPR), mono- and diglycerides (MD), soya lecithin (LSO) and sunflower lecithin (LSL) in three different concentrations were used. After conching, the emulsifier was mixed with 500 g of chocolate at a temperature of 50 °C and 500 rpm for 30 min using the Thermomix TM 6 mixer. The chocolates were evaluated in terms of particle size distribution, bending, acoustic, rheological, melting, colour and sensory properties. All emulsified chocolates exhibited reduced Casson plastic viscosity ( η c ) compared to the conched (STAN) and blended (MIX) samples, with the exception of PGPR_0.50. PGPR and MD showed higher viscosity values compared to lecithin samples. With increasing emulsifier concentration, a decrease in yield stress and thixotropy was observed for PGPR samples, while MD samples exhibited an increase in these parameters. In lecithin samples, a decrease in rheological parameters was observed up to the concentration of 0.50 w.%, while an increase in η c at 1.00 w.% was found. Particle size analysis revealed higher volume diameters Dv(90) for MD and PGPR samples (ranging from 18.60 to 23.30 μm) compared to LSO and LSL samples (from 18.30 to 19.00 μm). The melting temperature of the studied chocolates was determined using differential scanning calorimetry (DSC). In addition, cocoa butter polymorphs were observed using modulated DSC (MDSC). © 2026 The Authors. Thu, 01 Jan 2026 00:00:00 GMT http://hdl.handle.net/10563/1012811 2026-01-01T00:00:00Z