文摘
This work reports a comprehensive and scalable acoustic material preparation by a medium internal phase emulsion-templating technique from a single-part room temperature vulcanizable silicone rubber and pore generator (water and mineral oil mixture). By optimization of the mixing conditions, the pore-generator-volume and cure-schedule macroporous sound-absorbing silicone rubber was developed. By optical and scanning electron microscopy, the pore size, their interconnectivity, and heterogeneity were analyzed. For an optimized sample (0.5 volume-ratio water and 3.67 volume % mineral oil, porosity ∼83%, thickness ∼12.5 ± 1 mm) the average sound absorption coefficient and transmission loss measured by an impedance tube technique in 50−6400 Hz were ∼0.45 and 6.7−42 dB, respectively. Insertion loss measurements in 125–6300 Hz with the material as cladding inside (100%) and outside (85%) of an acoustical enclosure demonstrated minimum/maximum noise reduction of 2.31 dB at 630 Hz/20.9 dB at 4000 Hz and 3.55 dB at 400 Hz/13.71 dB at 2000 Hz, respectively.