Effect of Acoustic Intensity on Plate Polymeric Membrane

The actual acoustic intensity (I) that reaches membrane is measured by ultrasonic power measuring meter. I is altered by changing the height of membrane (H), the nominal ultrasonic power, or ultrasonic frequency in ultrasonic cleaner. The evolution of the property of polymeric membrane exposed to ultrasonic irradiation is followed by the calculation of membrane damage factor (R). Effect of acoustic intensity on the extent of membrane damage is investigated. The results show that the polytetrafluoroethylene (PTFE) membrane is comparatively resistant under ultrasonic irradiation, the polypropylene (PP) membrane is less resistant, but the nylon 6 (N6) membrane can be damaged seriously by ultrasound. When ultrasonic frequency is 45 kHz, I decreases from 1.04 W•cm-2 to 0.10 W•cm-2 as H rises from 3 cm to 9 cm; I increases from 1.04 W•cm-2 to 1.33 W•cm-2 as the nominal ultrasonic power rises from 200 W to 400 W, and R increases as I rises. When the nominal ultrasonic power is 200 W, I rises from 1.04 W•cm-2 to 1.45 W•cm-2 as ultrasonic frequency increases from 45 kHz to 100 kHz, but R generally remains stable when ultrasonic frequencies are 80 kHz and 100 kHz. Membranes are resistant under ultrasonic irradiation when ultrasonic frequencies are 80 kHz and 100 kHz.