Preparation And Properties Of Lightweight Foam Glass Sound Absorbing Material

With the development of industrial production, urban construction and transportation industry, the noise pollution is worsening and it has become a major pollution of the human social environment. It not only affects people’s work, study and life, but also harmful to human health. Currently, one of the main solution is to use sound-absorbing materials. Therefore, development of an excellent sound-absorbing material becomes very important. In this study, one kind of porous sound-absorbing material was prepared by the method of glass hollow microspheres sintering which was prepared with the waste glass as the raw material. The effects of different institution of glass sintering on structures and properties of glass hollow microspheres porous materials were researched in this study. And then the effects of structural factors such as open porosity, air-flow resistance, pore size, thickness and the cavity thickness on sound-absorbing properties of the porous materials were researched. There was another important study that was the improvement of sound-absorbing properties of the porous materials. We have tried a lot of methods, for example, surface piercing on the materials, compositing with the glass fiber, glass hollow microspheres composite sintering with the coal gangue hollow spheres. The main conclusions are as follows:1. Effects of sintering temperature and holding time on the properties of porous materials were researched: with the increase of sintering temperature, the pore size uniformity of the sample was worse, the average pore size of sample increased, and the compressive strength decreased; with the increase of holding time, the open porosity of samples increased and the compressive strength reduced first and then increased.2. The effects of structural factors such as open porosity, air-flow resistance, pore size, thickness and the cavity thickness on sound-absorbing properties of the porous materials were researched: With the increase of the open porosity of samples, the average sound absorption coefficient of the sample was increased first and then decreased. When the open porosity reached 93.2%, the average sound absorption coefficient of the material reached the maximum 0.42. As the average pore size of samples increased from 0.94 mm to 2.51 mm, the average sound absorption coefficient of the material tended to increase, and the maximum was 0.49. With the increase of the air-flow resistance of samples, the average sound absorption coefficient of the sample was increased first and then decreased. When the air-flow resistance reached 4.805×105 Pa·s/m3, the average sound absorption coefficient of the material reached the maximum 0.42. With the increase of the material’s thickness, the first resonance frequency fr moved to low-frequency direction. The sound absorption coefficient was significantly higher within the following range 1000 Hz. The average sound absorption coefficient has significantly improved, and the maximum can reach 0.57. With the increase of the thickness of the cavity behind the material, the material’s optimal absorption peak moved to lower frequency, and the sound absorption coefficient of the low frequency increased with the increase of cavity thickness.3. This part researched the ways to improve the sound absorption properties of the materials:(1) To improve the sound absorption properties by surface piercing on the materials: on the one hand, we ensured the same pore spacing and changed the pore size to obtain samples with different rate of perforation. The results show that with the increase of the rate of perforation, the sound absorption coefficient of materials has increased significantly from 0.37 to 0.65 over the frequency 1000 Hz and the value has no significant change under the frequency 1000 Hz. On the other hand, we ensured the same pore size and changed the pore spacing to obtain samples with different rate of perforation. The results show that with the increase of the rate of perforation, the sound absorption coefficient of materials has increased significantly from 0.37 to 0.54 over the frequency 1600 Hz.(2) To improve the sound absorption properties by compositing the materials and the glass fiber: adding an appropriate amount of glass fiber in the hole on the basis of surface piercing on the samples. The results show that the sound absorption coefficient of materials has increased significantly over the frequency 1600 Hz and the value has no significant change under the frequency 1600 Hz after adding the glass fiber in the hole.(3) To improve the sound absorption properties by the method of glass hollow microspheres composite sintering with the coal gangue hollow spheres. The results show that the pore size uniformity of the sample was worse and the whole sound absorption properties of the materials were certainly improved. When the content of coal gangue hollow spheres reached 15 wt%, the sound absorption coefficient of materials has increased from 0.17 to 0.21 under the frequency 400 Hz, and the sound absorption coefficient of materials has increased significantly from 0.35 to 0.57 over the frequency 400 Hz. The noise reduction coefficient NRC of the material increased from 0.22 to 0.34 over the entire frequency range.