Masayuki Okoshi

Development of Cotton Candy Method for High Productivity Polypropylene Fibers Webs

The cotton candy method (CoCAM) is developed for high productivity of polymer micro-and nano-fibers. Polypropylene was molten in a single screw extruder of the CoCAM at air pressures of 0.2-0.5 MPa with nozzle temperatures of 280-350 °C and the constant air temperature of 600 °C. The distance from the nozzle to the collector was set at 10-90 cm. Thermal images informed the accumulation of PP fibers flows at shorter collector distance. The diameters of PP micro-fibers decreased with increasing the air pressures and the nozzle temperatures. Crystallinity of the PP micro-fibers increased when increasing the nozzle temperature due to higher occasion of molecular orientation. The degree of the fiber entanglement in the PP micro-fibers decreased when increasing the collector distance, which affected on the declination of tensile strength. Ductility of the PP micro-fibers improved at high collector distances. The optimum condition of the PP micro-fibers was found at the average diameter of 2.3 μm at 0.5 MPa with the nozzle temperature of 340 oC collected at 60 cm. The productivity of the PP micro-fibers webs from the CoCAM was 144 g/h.

RETRACTED: Fabrication of Poly(Lactic Acid) Nanofibers by Cotton Candy Method

The poly (lactic acid) (PLA) fiber of biodegradable polymer was fabricated by cotton candy method with small nozzle. The air pressure was varied from 0.2-0.5 MPa with nozzle temperature of 210-260°C. The morphology of fiber was determined by scanning electron microscope (SEM). Thermal properties were examined using differential scanning calorimetry (DSC). SEM results suggested that diameters the PLA fiber at temperature 250°C and air pressure of 0.2 MPa were smaller than the fiber at low and high temperature. The sizes of the fibers were lower than 1 μm and the fibers were irregular size. Crystallinity significantly decreased when increasing barrel temperatures while it slightly changed when varied air pressure. The productivity of PLA fibers was around 30-180 g/h depended on controlled the nozzle temperature and the air pressure.