The traditional method of modifying the properties of polymeric materials is their filling with mineral particles. The use of synthetic nano-sized fillers in comparison with coarse-dispersed natural ones is very promising due to the large specific surface of nanomaterials. The study of such compositions by rheometric methods makes it possible to assess the structural changes that occur when nanoparticles are introduced into the polymer solution. In this study, studies were carried out in the mode of harmonic oscillations with solutions of cellulose acetate DAC in DMSO in the concentration range of 5-20% by weight. polymer containing 3 and 5% of the mass. amorphous silica. The experiments were carried out on a Haake MARS rotary rheoscope with a working cone-plane unit in the voltage range of 0.1-100 Pa and frequencies of 0.1-100 Hz at temperatures of 298, 318 and 338 K. Measurements of the frequency dependences of the complex viscosity, elastic modulus and loss modulus were performed at a constant voltage of 10 Pa. It was found that the DAC solutions in DMSO are non-Newtonian fluids that exhibit elastic properties with a DAC content of more than 10% by weight. It is shown that the concentration of AC, at which the solution begins to show elastic properties, decreases with increasing concentration of aerosil. For the DAC-DMSO-Aerosil system, there is a temperature-concentration range in which the elastic modulus is greater than the loss modulus, that is, the introduction of aerosil leads to a significant change in the system behavior during deformation. According to the data obtained, the concentration dependences of the enthalpies of activation of the flow of DAC solutions in DMSO and DAC-DMSO-aerosil systems were calculated.
|Date of Award||2018|
|Supervisor||Елена Витальевна Русинова (Supervisor)|