| Abstract [eng] |
This master's thesis reviewed the literature related to the history of polyurethane, reactions during synthesis, raw materials used in production and industrial production methods. The aim of this work was to determine the influence of the properties and quantities of materials used to synthesize elastic polyurethane foam in the compositions made for the synthesis on the quality indicators of the obtained product. This paper described the research methodology and the standards applied to it, according to which the tests for determining stiffness, elasticity, density, recovery time, and air permeability were carried out using the equipment intended for them. The influence of molecular weights of polyols and their amounts in the composition of polyurethane synthesis on the behavior of the synthesized product after formation and physical properties was studied and evaluated. After conducting the experiments, it was found that: when polyols of higher molecular weight are used for synthesis, the air permeability of all polyurethanes increases, stiffness decreases, and the structure does not change or changes slightly; increasing the amount of polyols of higher molecular weight in the composition of viscoelastic polyurethane leads to a shortening of the recovery time; increasing the amount of polyol of higher molecular weight in compositions of high elasticity and viscoelastic polyurethane produced using toluene diisocyanate almost does not change the sigh-back time and duration of foam growth, while in compositions of viscoelastic types produced with methylene diphenyl diisocyanate, the duration of foam growth decreases significantly; increasing the content of higher molecular weight polyol in the composition of viscoelastic polyurethane produced using toluene diisocyanate increases the density of the polyurethane; increasing the higher molecular weight polyol content increased shrinkage for viscoelastic polyurethanes, while shrinkage decreased for high elasticity polyurethanes when they were made with toluene diisocyanate; by increasing the amount of amines in the composition, reactions take place faster, number of defects in the foam increases, settling, density and air permeability increases, stiffness decreases, and the structure increases; reducing the amount of water increases the density, the duration of foam growth increases, sigh-back occurs later, air permeability and stiffness decrease, and settling does not change or changes insignificantly; increasing the amount of surfactant in the compositions reduces the risk of coalescence, reduces foam shrinkage, air permeability, stiffness and density, the structure becomes finer; when increasing the amount of tin octoate in the composition, settling decreases, but the foam begins to split due to an excess, the structure of the polyurethane also decreases, the density, duration of foam growth and air permeability decrease, but stiffness increases, the foam sighs-back earlier; by increasing the amount of toluene diisocyanate in the compositions, stiffness increases slightly, foam growth time increases, air permeability and density decrease, polyurethane becomes more sticky. Based on the results of the conducted research, recommendations and a technological scheme for synthesizing elastic polyurethane foam were made. |
