چكيده به لاتين
In this research, the mechanism of the mixing process and phenolic foam curing is investigated at first. Because in the process of foam-phenolic production, it is very important to have a constant and uniform structure, temperature and time control of the evaporation process of the foaming agent and the curing of the resin. Therefore, in the present study, we have tried to investigate the curing and mixing process of mixture. To do this, the differential calorimetry (DSC) and thermal-weighted analysis (TGA) were used. Also, the effects of increasing the foaming agent and the surfactant on cellular structure and mechanical properties of phenolic foam are investigated. In order to investigate the effects of resin viscosity on cellular structure and mechanical properties, resins with different viscosities are used. An electron microscope (SEM) image showed that the increase in the foaming agent caused cellular cohesion and, consequently, increased cellular size. Pressure tests did not show a regular trend, but in general, it may be said that increasing cell size eventually leads to a decrease in the mechanical properties of the phenolic foam, so that in the present study, the specific compressive strength has decreased by 63%. By increasing the surfactant due to reduce the surface tension of the resin, the cellular size reduces but cell density increases, which results in a decrease in the density of the foam. In high concentrations of surfactant due to the non-uniform distribution of this material in the mixture, the foam structure is defected. The viscosity of the resin has a tremendous effect on cell structure and cell size. By increasing the viscosity of the resin, the bubbles growth is limited and the cell diameter decreases. At the highest viscosity, cell size has dropped to 77 micrometers. Increasing the viscosity of the resin also leads to a much more uniform distribution of the cells in the foam, which is why the mechanical properties of phenolic foam have increased.
