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In this work, a hydrophobic intumescent flame retardant (HIFR) based on ammonium polyphosphate (APP), tannic acid (TA), CuO and polydimethylsiloxane (PDMS) was fabricated via an aqueous phase reaction. The surface of the HIFR was coated with spherical CuO nanoparticles and has a water contact angle of 130.6°. In comparison with APP, the HIFR exhibits higher flame-retardant efficiency and weakens the negative impact on the mechanical properties of TPU. The introduction of the 4 wt% HIFR results in 29.4%, 9.9% and 86.3% reduction in the peak heat release rate, total heat release and total smoke production of TPU, respectively. Meanwhile, TPU/4HIFR displays an increase in the Young's modulus, tensile strength and elongation at break of 8.3%, 13.1% and 12.2%, respectively, compared with TPU/4APP. It is of great significance to fabricate polymer composites with excellent flame retardancy and respectable mechanical properties. This work proposes a feasible strategy for the design of high-performance polymers with serviceable mechanical properties and low flammability, expecting to explore a series of practical applications in industry. [ABSTRACT FROM AUTHOR]

Under the condition of large water immersion, surface-piercing propellers are inclined to be heavy loaded. In order to improve the hydrodynamic performance of the surface-piercing propeller, the installation of a vent pipe in front of a propeller disc is more widely used in the propulsion device of high speed planning crafts. Based on computational fluid dynamics (CFD) method, this paper studied the influence of diverse vent pipe diameters on hydrodynamic performance of the surface-piercing propeller under full water immersion conditions. The numerical results show that, with the increase of vent pipe diameters, the thrust and torque of the surface-piercing propeller decrease after ventilation, and the efficiency of the propeller increases rapidly; the low pressure area near the back root of the blade becomes smaller and smaller gradually; and the peak of periodic vibration of thrust and torque can be effectively reduced. The numerical results demonstrate that the installation of artificial vent pipe effectively improves the hydrodynamic performance of surface piercing propeller in the field of high speed crafts, and the increase of artificial vent pipe diameter plays an active role in the propulsion efficiency of the surface-piercing propeller. [ABSTRACT FROM AUTHOR]