A novel underwater acoustically transparent material: Fluorosilicone polyester polyurethane

A novel fluorosilicone polyester polyurethane (FSPU) was successfully synthesized with polycaprolactone diol, toluene diisocyanate, hydroxyl fluorosilicone oil (FSO), and a chain extender, 2,4-diamino-3,5-dimethyl thiotoluene (E-300). It was characterized by Fourier transform infrared spectroscopy, dynamic mechanical analysis, and scanning electron microscopy. The water resistance, mechanics, and acoustic properties of the material were tested with an optical contact angle measuring device, an electronic universal testing machine, and sound field measurement, respectively. The results show that the water resistance of FSPU gradually improved with increasing FSO. Compared to that of polyurethane (PU), the water contact angle of FSPU at 50 wt % FSO increased to 111.7 degrees, and the water absorption reached a minimum of 0.8%. The glass-transition temperature of FSPU reached -44.1 degrees C; this was lower than that of PU. Moreover, the insertion losses of this material at 600 and 1000 kHz were only 129.2 and 267.3 dB/m, respectively; these values were 20.5 and 13.6% lower, respectively, than that of PU. The results indicate that FSPU had an excellent water resistance and acoustic performance and a low glass-transition temperature and is an ideal material for underwater acoustically transparent materials. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47894.