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 pre-expansion 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.