Past, present and future of pharmaceutical patents under Korea-US Trade Agreement

High efficiency fabrication of ultrahigh molecular weight polyethylene submicron filaments/sheets by flash-spinning

In this study, we propose a novel method for preparing continuous ultrahigh molecular weight polyethylene (UHMWPE) filaments by flash-spinning. The filaments were processed by calendaring to obtain the sheets. The morphology of the filaments and the sheets, the forming process, the optimal fabrication conditions, mechanical properties, spinning speed, and the rate of spinning of the filaments were investigated. The results showed that the filaments were composed of bunches of microfibers and the diameter of the filaments and the microfibers ranged from 0.15 mm to 0.22 mm and 0.2 μm to 5 μm, respectively. For a given concentration of 5 wt% of the UHMWPE, optimal specimens were obtained only when the temperature was in the range 150–210°C and the pressure was in the range 8–20 MPa. The spinning speed and the polymer consumption increased with enhancement in the pressure and the value reached as high as 47.2 m/s and 116.7 g/min, respectively. The properties and the spinning efficiency of the filaments revealed that flash-spinning is a potential method for manufacturing commercial products in various fields of application.