Research on the Influence of Basic Parameters of the Pre-Expansion of Granules Density

The paper presents the process of pre-expanded polystyrene used to produce models in the Lost Technology. There were research on preexpansion process in order to determine the effect of pressure and time for the initial expansion of the materials density. Analysis of the results confirmed that the higher the pre-expansion pressure is the materials density decreases. There was also a change in the intensity of the process in function of time and pressure, which may indicate the phenomena of material physical and chemical properties during the process.