Nanofibers have long been proposed for use in acoustic insulation as their benefits to acoustic insulation products are significant. Recent advances in production equipment have decreased the cost of bringing nanofiber production into a product, improved the qualities of the nanofibers and nanofiber webs, and allowed for easier integration with existing acoustic insulation production processes.
Sound is attenuated by air viscosity, nonreversible deformation of material, and thermal conduction between the fibers and the air. Sound absorption also depends on structural characteristics such as fiber fineness, density of the fiber, porosity, etc. Most of the acoustic energy is consumed by drag between the vibrating air particles and the pore surface where the velocity gradient decreases and kinetic energy of vibrating particles is changed into thermal energy. Sound is absorbed when it encounters a material which will convert some or all of it into heat, or which allows it to pass through not to return.
Sound absorption is measured as the sound absorption coefficient (α) – a dimensionless ratio of sound energy absorbed by a given surface to that incident upon the surface. It is a ratio of acoustic energy absorbed by the material and acoustic energy incident on that absorbing material; therefore it has a theoretical maximum value of 1. A part of the sound’s energy is absorbed and the rest is reflected back to the environment. As the absorption coefficient increases, the effectiveness of the acoustic insulation material improves.
Nanofibers can improve your acoustic insulation products by increasing the sound absorption coefficient, reducing material thickness, and decreasing material weight offering you a competitive advantage. The chart below shows the dramatic improvement in the acoustic performance of a traditional sound absorption material combined with nanofiber coated scrim.