Carbonized and Activated Non-woven as High Performance Acoustic Materials: Part II Noise Insulation

Noise can be reduced by sound barrier materials, and transmission loss (TL) measurements are used to determine the insulation performance of sound barriers. In this paper, TL of the non-woven composites with two surface layers and three base layers was measured and analyzed using Brüel and Kjær impedance tubes and Pulse software. The results show that non-woven composites with activated carbon fiber (ACF) non-woven as a surface layer had significantly higher values of average TL than glass fiber-surfaced composites in both the low frequency range (100—1600 Hz) and the high frequency range (1600—6400 Hz). Regarding the sound barrier performance, base non-wovens made of cotton and ramie were better than polypropylene-based non-wovens in the whole frequency range, while at the low frequencies, especially below 600 Hz, glass fiber-surfaced non-woven was better than ACF-surfaced non-woven. The composite with cotton non-woven as a base and ACF as a surface exhibited the highest average TL value of 8.56 dB and the lowest mass per unit area of 106 g/m ² .