Preparation of High Density Polyethylene (HDPE) Membranes via Thermally Induced Phase Separation

Microporous high density polyethylene (HDPE) flat plat membranes were prepared via thermally induced phase separation (TIPS) method. Paraffin oil and acetone were used as diluent and extractant in the preparation of membranes, respectively. Scanning electron microscopy was used to investigate the morphology of resulted membranes. Effects of polymer concentration, membrane and water bath temperature on membrane morphology, porosity and mechanical strength were investigated. The SEM images show that HDPE-paraffin oil system has leafy structure. Increasing the polymer concentration resulted in decreasing the membrane porosity and increasing the membrane mechanical strength as well. The resulted membranes illustrated that the slower cooling rate or higher water bath temperature allows greater growth of leaves like membrane structure. So higher porosity can be obtainted in higher water bath temperatures. Also higher mechanical strength was obtained at lower water bath temperatures as well as higher concentration, while an inverse trend was observed for the membrane porosity.