Acrylic Oligomer Based on Butadiene Dimer for Anti-Corrosion Surfacing

Постановка задачи. В задачу работы входила оценка эффективности модифицирующего влияния соолигомера 4-винилциклогексена с метилметакрилатом (ОБММА-50) на свойства антикоррозионного покрытия на основе сополимера КОРС, полученного с использованием кубовых остатков ректификации стирола для повышения технологических и эксплуатационных физико-механических характеристик исходного покрытия. Результаты. Установлены функциональные, структурные и конформационные особенности исходного сополимера и олигомерного модификатора, которые обеспечивают их совместимость при формировании антикоррозионного покрытия. Выявлен оптимальный рецептурный состав и эффективный интервал содержания акрилового олигомера, где наблюдается повышение технологических и физико-механических показателей исходного антикоррозионного покрытия от 15 до 100 %. Выводы. Показаны те особенности в структуре и составе исходного полимера и акрилового модификатора, которые обеспечивают существенное повышение физико-механических показателей покрытия, содержащего в своем составе оптимальную концентрацию акрилового олигомера. Statement of the problem. The objective of the work was to assess the effectiveness of the modifying effect of the 4-vinylcyclohexene co-oligomer with methyl methacrylate (OBMMA-50) on the properties of an anticorrosion coating based on KORS copolymer obtained using styrene rectification residues to increase the technological and operational physical and mechanical characteristics of the initial coating. Results. The functional, structural and conformational features of the initial copolymer and oligomeric modifier are established, which ensure their compatibility in the formation of an anti-corrosion surfacing. The optimal prescription composition and effective range of the acrylic oligomer content were revealed, where there is an increase in technological and physico-mechanical parameters of the initial anti-corrosion surfacing from 15 to 100 %. Conclusions. The features in the structure and composition of the starting polymer and acrylic modifier are shown that provide a significant increase in the physical and mechanical parameters of the coating containing the optimal concentration of acrylic oligomer in its composition.

Novel UV-activated biofunctionalization of up-converting nanocrystals for detection of proteins

Lanthanide doped nanocrystals capable to emit higher energy photons under excitation with lower energy radiation are promising for a broad range of applications including biodetection, biosensing, and bioimaging. However, the adaptation of these nanoparticles to the biological environment that requires good water-solubility, stability and ease of further functionalization still remains a challenge. The application of nanoparticles for biodetection or in various assays encountered many difficulties arising mainly from the strong tendency of nanoparticles for aggregation or nonspecific binding. Here we present a new method to obtain soluble and stable in water-based buffers NaYF4:Yb3+Er3+ nanocrystals with modified surface ready for further conjugation with biomolecules. In the presented approach polyvinylpyrrolidone/vinyl alcohol copolymer (PVP/VA) with photo-activatable linker (N-5-Azido-2-nitrobenzoyl group—ANB-NOS) was used for initial coating due to its high non-covalent affinity to nanoparticles surface. Subsequent coating with aminated dextran by ultraviolet light activation of ANB-NOS was carried out. This step has a significant impact on nanocrystals stability in the physiological buffer as well as on protein conjugation. Conjugation of biomolecules was possible by employing another photo-linker—sulfosuccinimidyl 4,4′-azipentanoate (sulfo-SDA). Bacterial Protein G has been selected to create a universal immune-imaging agent due to its ability to bind Fc fragment of most mammalian immunoglobulins. Moreover, the direct attachment of antibodies to nanoparticles was also examined. The activity of biofunctionalized nanocrystals was tested in immunoblot test, that confirmed preserved activity of attached molecules and lack of undesired nonspecific binding or precipitation on the assay membrane. Graphic abstract

PCL-TiO2 nanocomposite to improve ageing of offset prints

UV radiation or sunlight can affect the printed sample by fading the ink surface and therefore the product losses it's decorative purpose and becomes less desirable to the customer. To create the efficient protective coating, titanium dioxide (TiO2) will be used as a well-known compound that should lower the effects of UV radiation. TiO2 should lower the colour fade after UV radiation and this will be determined by densitometric and colorimetric (CIE L*a*b*) measurements. In addition, measurement of print gloss will also be conducted to evaluate visual appearance of the sample. Biopolymer Polycaprolactone (PCL) was the base of the PCL-TiO2 composite in which TiO2 nano sized. To determine influence of the amount of TiO2, three composites were prepared by adding different weight ratio of the TiO2. The prepared nanocomposites were then applied onto the offset prints on gloss art print paper and on the uncoated paper. The results have shown that TiO2 coating does affect ink’s density, colorimetric properties and print gloss after initial coating. The change in chroma due to the accelerated ageing is most visible on yellow ink, cyan and magenta proved to be the more stable. Accelerated ageing caused change in the L* of black. On all colours, increase of the TiO2 weight ratio improved resistance of colour to change. Coated gloss paper was more resistant to density change where uncoated had lower change in chroma. It could be concluded that TiO2 has the ability to protect the prints in the measured time interval but it has to be noted that concentration of the TiO2 particles also causes colour difference and must be observed when defining composure of the nanocomposite.

In situ thermal-conductivity measurements and morphological characterization of intumescent coatings for fire protection

Thermal insulating performance and char-layer properties have been studied for water-based intumescent coatings for structural steel fire protection using a new laboratory-scale mass-loss cone apparatus. A specimen (100 × 100 mm mild steel plate; the initial coating thickness: 0.3–2.0 mm) is placed horizontally and exposed to a constant incident radiant heat flux (25, 50, or 75 kW/m2). The apparent thermal conductivity of the expanding char layer is determined in situ based on real-time measurements of the temperature distribution in the char layer and the heat flux transmitted through the char layer. Three-dimensional morphological observations of the expanded char layer are made using a computed tomographic–based analytical method. The vertical variation of the porosity of the expanded char layer is measured. The measured heat-blocking efficiency is correlated strongly with the incident heat flux, which increases the expanded char-layer thickness, and porosity for sufficiently large initial coating thicknesses (>0.76 mm). For a thin coating (0.30 mm), violent off-gassing disrupts the intumescing processes to form a consistent char layer after abrupt exposure to higher incident heat fluxes, thus resulting in lower heat-blocking efficiency. Therefore, the product application thickness must exceed a proper threshold value to ensure an adequate thermal insulation performance.