The production and characterization of polymer foam material for automotive industry

In this study, PP polymer, 20%talc filled PP (PP-T) and 20%talc/EPDM filled PP (PP-T-EPDM) polymer foam materials were produced with using injection parameters such as injection pressure (60, 80 and 100 bar), injection speed (60, 80 and 100 mm/s), back pressure (20, 60 and 100 bar) and melt temperature (160, 170 and 180oC). To produce foam materials, chemical foaming agent was used, and added to polymer materials as 1wt.% and 2wt.%. The mechanical properties of foam samples were determined depend on process parameters and, optimum parameters determined by taking into lightness and strength properties of samples. Cell morphology characterization such as cell diameter, cell count, distance between cells, skin layer thickness and cell density, and mechanical properties such as tensile and impact strength of polymer foams were examinated. DSC and TGA analysis realized for determined thermal properties of polymer foams. In addition, the effect of nano-clay was investigated on polymer and foam materials. Modified nano-clay with onium ion filled PP and PP/EPDM based polymer nano composites and foams were produced. X-Ray diffraction (XRD) was used characterization of nano-clay filled nanocomposites. Process parameters such as injection pressure, injection speed, back pressure and melt temperature, and amount of foaming agent was affected cell morphology and mechanical properties of polymer foams. Generally, closed-cell foam structure was obtained. The most important parameters affecting the cell morphology has been found that injection pressure, melt temperature and amount of foaming agent. With increasing the amount of foaming agent, cell density increased, foam density and mechanical properties decreased. Talc mineral act as a nucleating agent, and influenced both mechanical properties and cell morphology of polymer foam material. In general, as compared with unfoamed PP, density reduction were obtained about 9-19% for PP foam, 10-27% for PP-T and 10-24% for PP-T-EPDM foam. Nano clay that used as alternative to talc minerals have been effective in increasing the mechanical properties. With increasing amount of nano-clay, tensile and modulus of elasticity increases, impact and % elongation values decreased. Tensile strength, impact strength and elongation at break values increased with the addition of PP-g-MA compatibilizer to the polymer and polymer composites.