The mechanism of preparing thermoset foam from melamine and formaldehyde as raw materials was illustrated in analyzing the variations of infrared spectroscopy and viscosity as well foam microstructure. Physical foaming occurred with crosslinking solidification resulting in different foams in hole size and length-radius ratio with different conditions. Process parameters were optimized through orthogonal experiments for light

noise-reducing and good compression resilient foam material. The optimal melamine foam with density of 5 kg·m-3 was obtained after 60 s microwave heating resin solution with viscosity of 1500 mPa·s including resin

emulsifier

n-pentane foaming agent and formic acid solidifier in weight ratios of 50:2:16:4.