Polycarbonate/nano silica composites were prepared by twin screw extrusion method. The storage modulus

loss factor and sound insulation properties of the composites were tested. The results show that the storage modulus of the composite increases and the peak value of the loss factor decreases gradually with the increase of the addition amount of nanosilica;the weighted sound reduction index of 5 mm polycarbonate matrix material is 24.4 dB

and the sound insulation performance of the composite material is significantly improved after adding nanosilica filler;and the weighted sound reduction index reaches 27.5 dB when the amount of nanosilica is 3 phr. The particle size of the filler has little effect on the sound insulation property of the composite

and the sound insulation property of the composite decreases slightly with the increase of the particle size.