| Melamine foam has a wide application in construction, traffic and other areas due to its lightweight, flame retardation, sound absorption performance, heat- insulating property and low price of raw materials. And it could be used as matrix material of textile composite. The property of the foams could be improved by adding flexible textile materials into them,thus expanding the application of foam and textile materials. However, the research of melamine foam is mainly focused on forming process and mechanical modification. While the sound property is always ignored. The foam structure is the important factor affecting sound absorption. It is meaningful to study the sound absorption characteristics of melamine foam with different structures, which help to enhance its noise reduction efficiency in different environments. Meanwhile, the rigid melamine foam has high brittleness and low strength which could restrict its application in industry. So it is worth to study the compressive property of foams.Therefore, we studied the effect of the preparation parameters on the structure of foams prepared by adjusting preparation process, then analyzed the influence of the structure on sound absorption performance and compression property of melamine foam. And we preliminary explored property and structure of the foam prepared by adding chopped glass fibers in foam.Firstly, we studied the influence of foam preparation parameters on pre-foaming resin in order to study the effect of that on foaming process and foam structure.Then, scanning electron microscope(SEM) was used to observe the structure of melamine foam. And the influence of the preparation technology on the microstructure of melamine foam was studied. The results showed that the lower the water content of resin was, the smaller the pore size of the foam and the larger the apparent density would be. Under different catalysts, the foam structure was different and the foam prepared by formic acid had closed cell structure. When the amount of anionic surfactant SDBS was 3%, the foam showed a fine and uniform structure and a high closed cell content. After adding chopped glass fiber in foam, it was found that the pore size of the foam tended to decrease with fiber content increased.Finally, we tested sound absorption coefficient and compressive strength of the foams prepared in different preparation parameters, then in combination with cell structure, analyzed the effects of the structure on property of the foam. The research found that with the increase of foam density and the decrease of pore diameter, the sound absorption coefficient of the foam increased first and then decreased at medium frequency and high frequency bands. Sound absorption performance of the foam with three-dimensional network structure was enhanced with pore size decreased. Compared with that, the sound absorption performance of closed-cell melamine foam was better at low frequency bands and worse at medium and high frequency bands. And with the decrease of the closed cell content of melamine foam, sound absorption performance of the foam increased at the whole frequency bands. It was found that adding fiber could effectively improve the sound absorption performance of the foam at low-frequency bands.The research on compression property showed that at the same density, the compressive strength of open cell foam with small pore size was greater. And the closed-cell melamine foam had better compressive property than the open-cell foam. The research showed that the smaller the cell diameter was, the better the compressive strength of the closed-cell foam would be, but the broken and cracked cell wall decreases the compressive strength. It was found that adding fiber could effectively improve the compressive strength of the foam.The results showed that the preparation process has important influence on the structure and performance of melamine foam. The sound absorption performance and compressive property of melamine foam with different structures had significant differences. |
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