Research
Synthesis and Characterization of Polyimide Thin Films by Thermal Evaporation and Solid State Reactions
In this research we describe the preparation of polyimide with pyromellitic dianhydride (PMDA) and p-phenylene diamine (PDA) thin films by physical vapor deposition. For this study, FTIR Spectrometer has been used to measure the effect of imidization temperature on the chemical structure of vapor-deposited thin films of the aromatic PI. When temperature increases, a general increase in all the absorption peaks is observed. This suggests that residual PAA monomers continue to be converted into PI. The surface topology of the PI films was further examined by using AFM atomic force microscopy as a function of the imidization temperature at 150,200,250oC for 1 hour each, it can be clearly seen that the surface became rougher with increasing imidization temperature. The thermal stability of polyimide was also improved by using Thermo gravimetric analysis (TGA).
Physical Properties of Polymer Filled with Inorganic (Granite) Filler
In this study the physical properties such as the thermal conductivity, thermal diffusivity, porosity and density of the epoxy composites were characterized as a function of weight fraction of granite. According to the test results, addition of granite increases the thermal properties of the composites. This is due to the smaller interfacial thermal barrier at the interface between the particles and the matrix, and the easy pathway among particles, and we can say decrease of apparent porosity and increase in density because of the highest density of granite comparable with density of epoxy.
