1. Photochemical behavior of colloidal lignin particles under controlled UV exposure : balancing self-stabilization and degradationJulia Tomasich, Rene Alexander Herrera Diaz, Anna Malgorzata Sandak, Michael Harasek, Stefan Beisl, Oihana Gordobil, 2025, original scientific article Abstract: Colloidal Lignin Particles (CLPs), with their polyphenolic structure, are promising sustainable alternatives to chemical UV filters. This study investigates the photochemical behavior of CLPs under ultraviolet irradiation synthetized from five different technical raw lignins (Alkali, Organosolv, two Enzymatic Hydrolyzed and Softwood Kraft Lignin) via solvent-shift procedure. The suspensions were irradiated using a self-developed UV-pen set-up and a commercially available UV chamber, enabling controlled UV exposure over time. Variations in the physicochemical properties of irradiated colloidal lignin particles were characterized by Multi-Angle Dynamic Light Scattering (MADLS), Fourier Transform Infrared Spectroscopy (FTIR) coupled with chemometrics, UV–Vis spectroscopy, and High-Performance Size Exclusion Chromatography (HP-SEC). CLPs exhibited comparable responses after 14 days of UV exposure, with alterations in particle chemistry, particularly in the formation of new functional groups and molecular rearrangement. Moreover, the photochemical stability of CLPs was found to be highly dependent on both their concentration and the nature of the dispersion medium (aqueous, hexane-based, and solid-state). At higher concentrations (1.8 mg/mL), CLPs demonstrated effective self-stabilization, while lower concentrations led to rapid degradation, resulting in the disappearance of particles and the formation of low-molecular-weight fragments. Additionally, Minimal photochemical changes were observed in non-aqueous or solid-state environments due to restricted molecular mobility. These findings provide valuable insights into the degradation pathways and stability across different environmental contexts, which can contribute to understanding the potential environmental impact of CLPs in aquatic ecosystems.
Keywords: biobased materials, lignin colloidal particles, photodegradation, UV-irradiation, spectroscopy
Published in RUP: 09.09.2025; Views: 455; Downloads: 5
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2. Feasibility of portable NIR spectrometer for quality assurance in glue-laminated timber productionJakub Michal Sandak, Peter Niemz, Andreas Hänsel, Juana Mai, Anna Malgorzata Sandak, 2021, original scientific article Keywords: near infrared spectroscopy, glue-laminated timber, glulam, delamination, quality assurance
Published in RUP: 18.10.2021; Views: 4214; Downloads: 26
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3. Oriented investigations on the application of NIR spectroscopy for the evaluation of the bonding quality of glued laminated timber from hardwoodPeter Niemz, Jakub Michal Sandak, Juana Mai, Andreas Hänsel, 2021, published scientific conference contribution abstract Keywords: wood gluing, ash wood, delamination, NIR spectroscopy, Micro-NIR, hyperspectral imaging, quality control
Published in RUP: 16.07.2021; Views: 3203; Downloads: 78
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4. Brain imaging with functional near-infrared spectroscopy in educational researchNežka Sajinčič, Anna Malgorzata Sandak, Jakub Michal Sandak, Andreja Istenič, 2021, published scientific conference contribution abstract Keywords: functional near-infrared spectroscopy (fNIRS), functional neuroimaging, educational research, ecological validity, electro-encephalography (EEG), functional magnetic resonance imaging (fMRI)
Published in RUP: 06.05.2021; Views: 2912; Downloads: 16
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6. Impact of drying process on kraft lignin : ligninwater interaction mechanism study by 2D NIR correlation spectroscopyOihana Gordobil, Rene Alexander Herrera Diaz, Faksawat Poohphajai, Jakub Michal Sandak, Anna Malgorzata Sandak, 2021, original scientific article Keywords: hardwood kraft lignin, drying temperature, DVS, NIR spectroscopy, 2D-COS
Published in RUP: 06.05.2021; Views: 3655; Downloads: 11
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7. A method for accelerated natural weathering of wood subsurface and its multilevel characterizationAnna Malgorzata Sandak, Jakub Michal Sandak, Marion Noël, Athanasios Dimitriou, 2021, original scientific article Keywords: photodegradation, wood weathering, SEM imaging, FT-IR spectroscopy, thin samples, accelerated natural weathering
Published in RUP: 04.02.2021; Views: 2576; Downloads: 40
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10. Long-term corrosion behavior and biocompatibility testing of titanium-based alloy covered with nano-crystalline hydroxyapatiteMonica Popa, Cora Vasilescu, Silviu Iulian Drob, Julija Hmeljak, Andrej Cör, Jose Maria Calderon Moreno, 2015, original scientific article Abstract: In this paper, we applied on the surface of the new Ti%20Nb%10Zr%5Ta alloy nano-crystalline hydroxyapatite (HA) coating by the method of the chemical deposition in a solution supersaturated with Ca2+ and inline image ions. The composition and crystallinity of the obtained coating was determined by X-ray diffraction, micro-Raman, infrared, and energy dispersive X-ray spectroscopies and its morphology and porosity by scanning electron microscopy. The coating long-term corrosion behavior for 3000 soaking hours in simulated human fluids (Ringer's solutions of different pH values) was studied by cyclic potentiodynamic and linear polarization, electrochemical impedance spectroscopy and monitoring of the open circuit potentials and corresponding open circuit potential gradient due to the pH non-uniformity of the biofluid. Also, the coating biocompatibility was performed by cells (human osteoblast % HOS and human immortalized pulmonary fibroblast % Wi-38) adhesion and proliferation testing in the HA coated bioalloy extract compared to respective effects of the un-coated bioalloy extract. The initial HA nano-coating promoted the deposition of new HA layers, thickening itself and showing its ability to induce the formation of this main inorganic component of the human bone, therefore denoting bioactivity of the HA nano-coated alloy.
Keywords: bioactive hydroxyapatite, corrosion behavior, EDX, FT-IR, Raman micro-spectroscopy, SEM, XRD
Published in RUP: 09.08.2016; Views: 5739; Downloads: 233
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