Abstract:

In order to reduce the vibration and air noise of ship deck, damping polyurethane was prepared from branched and linear polyols and low viscosity polymethylene polyphrnyl polyisocyanate(PMDI), and laid between steel deck and floating deck. The effects of matrix structure and damping filler on the curing time, leveling, damping and mechanical properties of damping layer were studied. The sound insulation performance of decks before and after laying damping layer was discussed. The results show that adjusting the mass ratio of branched and linear polyols can change the degree of crosslinking and the structure of the matrix. Branched polyols improve the cure rate, hardness, and mechanical properties. Linear polyols reduce the glass transition temperature of the system. The damping temperature range appears at high temperature and the loss factor peak value increases. A two-milimeter-thick polyurethane damping layer under an existing floating deck structure effectively increases the average sound insulation by 3 dB, and the effect is greater in the low frequency range. The polyurethane damping layer has excellent fluidity, controllable curing time and convenient self-leveling construction, which is of practical significance for improving the sound reduction performance of the existing floating deck.

Key words: branched polyol, polyurethane, self-leveling, damping performance, sound reduction