Abstract:
Fibreglass, foam, mineral fibres and their composites are the conventional materials used in applica tions that require absorption of sound. However, due to the health risks associated with the traditional materials, textile fibrous structures are becoming a valid alternative in spite of their comparatively lower sound absorption properties. The existing textile structures and textile structures specifically modified physically or chemically to enhance sound absorption properties have been experimented for better performance in sound-related properties. The fibres have been chemically modified using plasma treatments and alkali treatments, while microfibres, nanofibres, hollow fibres, bicomponent fibres, crimp fibres and aerogel-treated fibres are produced to modify the physical structures of fibres. The basic principle employed in these fibre modifications to enhance sound absorption is the increase of energy dissipation by increasing the fibre surface area, fibre roughness and tortuosity of the mater ial. This article critically reviews the techniques of modifying the fibrous structures to enhance sound absorption properties and their effectiveness. The sound absorption coefficient of natural fibres can be enhanced up to 0.9 in mid and high frequencies by alkali treatments, while the sound absorption coefficients of microfibres, hollow fibres, bicomponent fibres and nanofibres significantly higher than regular fibres.
