Investigation of the effect of die diameter on the structural properties of extruded polyethylene foams

Document Type : Original Article

Authors

1 MSc Graduate, Faculty of Mechanical Engineering, Urmia University, Urmia, Iran

2 Professor, Department of Mechanical Engineering, Urmia University, Urmia, Iran

3 Faculty of Mechanical Engineering, Urmia University, Urmia, Iran

4 PhD Student, Faculty of Mechanical Engineering, Urmia University, Urmia, Iran

10.22034/ijme.2024.433989.1907

Abstract

Polymeric foams are of great importance due to their special features such as lightweight, heat, and sound insulation properties. Also, production of polymeric foams saves the consumption of materials due to the use of less raw materials. As a result, it reduces the pollution in the environment. Researchers have shown that by increasing the cell density and decreasing the cell size, better properties of polymeric foams can be achieved. It is accessible by increasing the pressure drop rate of the system with changes in the geometry of the extrusion mold. In this research, the effect of mold geometry, including mold diameter, was assessed on the structural properties of polyethylene foams produced by the physical foam extrusion method with carbon dioxide foaming agent at a process temperature of 130 °C and 2 wt% of nucleating agent. The diameter of the mold was set at 1, 2, and 3 mm to create different pressure drop rates. The results showed that the decrease in the diameter of the nozzle caused an increase in the system pressure. This increase of 1 mm resulted in the system pressure prevailing over the gas injection pressure and caused insufficient gas to enter the system. In the sample with a 2 mm, the pressure of the gas entering the system was higher and the expansion was about 2.25 times, which is more than the 1 and 3 mm molds.

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