A study on the Improvement of the sound insulation performance of polymeric film

초록

The sound insulation performance of a film is assessed by the degree of dissipation of airborne sound wave energy transmitted across the film, i.e., the difference in acoustic energy between before and after passing through the film. According to the correlation between the physical properties and acoustic energy of a polymer, effective dissipation of energy is equivalent to effective damping of the film. Damping, i.e., energy dissipation, of a polymer is the ratio of the loss modulus (E？？) induced by its viscous property with respect to the storage modulus (E？) induced by its elastic property when energy is applied to the polymer. This ratio is denoted by tan δ, which always peaks in the vicinity of the glass transition temperature. It was therefore assumed that the film would show superior damping performance in the vicinity of its glass transition temperature. Thus, we examined the correlation between the glass transition temperature of a film specimen and its sound insulation performance. As a result, it was determined that the overall excellent results of sound insulation performance demonstrated by the reference materials, PVB(Polyvinyl butyral) and the EVA(Ethylene-vinyl acetate) films, were correlated with the glass transition temperature range of the respective films. In particular, some of the tested films, which were thinner than the PVB film, exhibited sound absorption rates similar or superior to that of the PVB film despite their thinness. This indicates the need for performance improvement of the currently used PVB films and the potential of other films to replace PVB films when appropriate. In this study, the correlation between the physical properties of a film and its sound insulation performance was quantitatively analyzed. The results demonstrated that the sound insulation performance of a film can be efficiently improved according to the conditions of its application.