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Betulin is a promising natural organic substance due to its antibacterial, fungicidal, and antitumor properties, as are their derivatives. The particle size of betulin can reach several tens of micrometers, and its thickness is several microns. There are various ways of processing betulin, but the most promising are solution methods (applying thin layers, impregnation, etc.). Application or impregnation of various materials is carried out using betulin; however, currently known solvents do not allow obtaining solutions with the necessary content of it. Since a number of direct solvents are already known for betulin, which provides only low-concentration solutions, the use of complex systems based on two solvents can become the optimal solution to the problem. The literature data show that the use of mixtures of solvents allows for the preparation of homogeneous solutions, for example, for natural polymers like cellulose, etc. This approach to obtaining solutions has become the basis for the processing of betulin. The use of a mixed solvent based on ethanol and DMSO for the preparation of betulin solutions has been proposed for the first time. The solubility of betulin in a mixture system with a ratio of components of 50 wt.% to 50 wt.% was studied, and a solubility curve was plotted. It is shown that the use of a two-component solvent makes it possible to transfer up to 10% of betulin into solution, which is almost twice as much as compared to already known solvents. The rheological properties of the obtained solutions have been studied. The viscosity of betulin solutions in a complex solvent depends on its content and temperature, so for 7% solutions at 70 °C, it is approximately 0.008 Pa*s. Applying betulin to the surface of the cardboard increases its hydrophobic properties and repellency.
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Specific viscosity of polymer solutions with large thermal blobs
Literature viscosity data are reviewed in both entangled solutions and semidilute unentangled solutions, with several examples of using de Gennes’ thermal blob to rationalize observations for flexible polymers dissolved in intermediate quality solvents. Some puzzling literature data in θ-solvents are also nicely understood with two parameter scaling upon reanalysis (where the correlation length and the tube diameter concentration dependences differ). However, some literature data seem to not be understood with this simple scheme, suggesting that our understanding of neutral polymer solution viscosity is incomplete. Lastly, combinations of experiments are suggested to better examine the concept of the thermal blob.
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- Award ID(s):
- 2203746
- PAR ID:
- 10514637
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- Rheologica Acta
- Volume:
- 62
- Issue:
- 11-12
- ISSN:
- 0035-4511
- Page Range / eLocation ID:
- 687 to 693
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s00397-023-01419-7
