The sound insulation property of composite from waste printed circuit board and unsaturated polyester

The sound insulation property of Waste printed circuit boards (WPCBs)/unsaturated polyester (UP) composite plate has been investigated. The effect of WPCB particle size and mass ratio on the surface density, elastic modulus and weighted sound reduction index has been studied. The results showed that WPCB addition caused the surface density increase especially for coarse particle because of the metal particle existence. The elastic modulus value was susceptible to the UP sufficiency to high WPCB mass ratio. The WPCB-UP composite plate shows sound insulation application potential because the maximum weighted sound reduction index of composite plate with particle size <0.71 mm reaches 28.4 dB. The composite sound transmission loss, which is the sound insulation property at different frequency, was measured by the four-microphone impedance tube method in the frequency range from 100 to 3150 Hz. The theoretic resonance frequencies predicted by the stiffness and mass laws were close to the experimental ones. The STL difference in stiffness-controlled region was more obvious than that in mass-controlled region because the addition of WPCB leaded to much greater increase in the stiffness than that in surface density.