Study On Sound Absorption And Insulation Performance Of EVA Foaming Materials

The foam materials as a kind of multi-functional new materials composed of solid phase and gas phase,because of its excellent overall performance,in recent years in the industrial field has been widely used,especially in the decorative materials is particularly prominent.For example:aluminum foam,polyurethane and polyvinyl chloride.However,these materials are expensive,fragile and pollute the environment and other issues,especially in the course of the experiment will leave some harmful substances in the human body,such as isocyanate residues,while burning polyurethane foam materials will produce some toxic gases.More importantly,most of the research focused on adding filler materials or changing the thickness of the materials to improve the sound absorption and thermal insulation properties of the materials,and by adjusting the foam quality to improve its sound absorption,thermal insulation performance research is very small and not system,in-depth.EVA foam materials as a multi-functional environment friendly polyolefin materials,the system of its sound absorption performance in order to replace the existing materials is of great significance.In this paper,EVA foaming materials were prepared by molding and extrusion foaming method.The influence of foaming quality and external conditions on the sound absorption and heat preservation performance were analyzed systematically by using the sound absorption mechanism and thermal insulation mechanism of porous materials.This broadening the application of sound absorption and insulation materials have some guidance.The main research contents are:(1)The EVA foaming materials was prepared by molding and extrusion foaming.The porosity,cell size,cell structure type,cell type and layer number were analyzed by the sound absorption mechanism.The law of sound performance;(2)The effects of porosity,cell size,cell wall thickness,cell structure type,filling gas type and temperature on the thermal insulation properties of foamed materials were studied by means of heat preservation mechanism.Get the following conclusions:(1)Porosity and cell size were 79.1%,71.3?m is the best foam quality of foam materials,sound absorption and insulation performance is ideal.When the cell structure type is open type,the noise reduction coefficient and sound absorption coefficient are large,respectively 0.49,0.595(1000Hz),sound absorption performance is obvious,poor insulation performance;when the cell wall thickness and cell type Respectively,8.2?m and closed type,the insulation characteristics of the ideal,poor sound absorption.(2)When the filling gas inside the cell is H2,the sound absorption coefficient of the foaming materials at the frequency of 800 Hz is 0.553,the sound absorption characteristic is better,and when the filling gas becomes N2,the insulation performance is ideal.(3)When the number of layers of foam material is 5 layers,the sound absorption coefficient and noise reduction coefficient are the highest at the low frequency of 500 Hz,which is 0.585 and 0.518 respectively,and the low frequency sound absorption effect is better.(4)The thermal conductivity of the foamed material tends to increase with the increase of temperature.The thermal conductivity of the foamed material is 0.042 W/(m·K)when the material is at room temperature 25 ?,insulation characteristics of the ideal.