Experimental and theoretical investigation of sound transtmssion loss for polycarbonate, poly(methyl methacrylate), and glass

In this study, the effects of the soundproofing properties of polycarbonate (PC), poly(methyl methacrylate) (PMMA), and glass were investigated. We fabricated the specimens into 3 mm thick sheets by direct hot compression molding as a monolithic sample and also by gluing three thin sheets together into a multilayer. Sound transmission loss (STL) was measured by an impedance tube over the frequency range 63-1600 Hz. The results indicate that because of the close density, the STLs for PC and PMMA were almost the same above 1200 Hz. Also, PMMA had a greater STL than PC in the range 63-300 Hz. In a comparison of the monolithic and multilayered samples, we demonstrated that the epoxy-based adhesive interlayers had more efficient bonding than the silicone-based ones. The multilayered polymer/silicone specimens showed a sharp drop in the STL values compared to the monolithic samples. However, the multilayered polymer/epoxy specimens revealed similar behavior to the monolithic polymers. (C) 2015 Wiley Periodicals, Inc.