Publications by authors named "Krasnou I"

In this study, we explored the selectivity of softwood lignin toward esterification through chloromethylation. Organosolv pine lignin chloromethylated by a novel greener protocol was subjected to esterification with decanoic acid (C10), tetradecanoic acid (C14), and stearic acid (C18). The success of lignin esterification was confirmed by using FTIR and NMR spectroscopy.

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Invited for this issue's cover are researchers from Tallinn University of Technology (TalTech). The image depicts the lignin chemical evolution route from raw biomass through a greener chloromethylation procedure developed by the research team. It showcases the transformation into lignin-supported metal nanoparticles, serving as a catalyst for various chemical reactions in both batch and continuous flow conditions.

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Article Synopsis
  • Researchers synthesized cellulose palmitates (CPs) using a catalyst-free method in a superbase ionic liquid environment, focusing on varying degrees of substitution (DS) influenced by temperature, time, and vinyl palmitate ratios.
  • * The study detailed the effects of reaction conditions on CPs' structural composition, revealing the importance of specific hydroxy groups in the transesterification process and identifying optimal conditions that result in a DS between 0.5 to 2.3.
  • * Various spectroscopic methods verified the CPs' chemical structure and stability, while comparisons of untreated and regenerated cellulose highlighted changes in their properties due to the ion liquid system used.
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We present a novel, greener chloromethylation procedure for organosolv aspen lignin under mild reaction conditions without Lewis acid as a catalyst and in acetic acid as a solvent. This synthetic protocol provides a reliable approach to chloromethylated lignin (CML) and means to obtain valuable lignin derivatives. The resulted CML was subsequently transformed into 1-methylimidazolium lignin (ImL), which effectively serves as a stabilizing agent for Pd/CuO nanoparticles (Pd/CuO-NPs).

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Article Synopsis
  • The study presents a new method for transesterifying cellulose with vinyl esters using an environmentally friendly ionic liquid, [mTBNH][OAC], allowing for improved homogeneous reactions and recyclability.
  • Various long-chain cellulose esters were synthesized, achieving a degree of substitution (DS) up to 1.8, with optimized reaction parameters such as temperature and reactant ratios.
  • Structural and thermal analyses indicate successful incorporation of alkyl chains into cellulose, enhancing material properties and suggesting these esters could replace traditional cellulose derivatives.
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The circularity of polymer waste is an emerging field of research in Europe. In the present research, the thermal, surface, mechanical, and tribological properties of polypropylene (PP)-based composite produced by injection molding were studied. The pure PP matrix was reinforced with 10, 30, and 40% wt.

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Thermoplastic cellulose esters are promising materials for bioplastic packaging. For that usage, it is important to understand their mechanical and surface wettability properties. In this study, a series of cellulose esters are prepared, such as laurate, myristate, palmitate, and stearate.

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Novel composite self-disinfecting films of polylactic acid (PLA) filled with nanosized particles of double sodium-copper(II) paratungstate B NaCu(CuOH)[WO(OH)]·32HO (POM) were developed. The solvent casting (POM/PLA film) and solvent-free melt extrusion methods (Extr. POM/PLA film) were applied for film preparation.

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Water-soluble, partially cross-linked poly-2-isopropyl-2-oxazoline combining the properties of chemical and physical gels was synthesized by a two-step procedure. Thermally induced sol-gel transition in its aqueous solution was studied by rheology, light scattering, and turbidimetry. It was demonstrated that the synthesized product is bimodal; it consists of linear and cross-linked components.

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Cellulose esters with long carbon side chains (e.g. stearate) were produced via a homogenous reaction in ionic liquids.

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