The low thermal conductivity of the EPS foam layer is mainly due to the large number of tiny pores contained in its internal structure. These pores are tightly closed and connected to each other, forming a good thermal insulation barrier. The thermal conductivity of EPS foam is relatively low, approximately between 0.03-0.04W/m.K. This low thermal conductivity makes EPS foam an excellent thermal insulation material.
The reason why EPS foam has excellent thermal insulation effect is also because the air trapped inside is a poor conductor of heat. Unlike foams that contain other gases, the air remains in the honeycomb for a long time, so the insulation effect is stable. In addition, the closed and foamed spherical molecular structure of EPS foam board is not only relatively light in weight and has good dimensional stability, but also is non-toxic and has superior performance. This structural design further enhances its thermal insulation performance.
In practical applications, a 6cm thick EPS insulation layer can significantly reduce the heat flow from the surface to the deep layer, effectively slow down the freezing and thawing process of permafrost, maintain stability and reduce deformation. This shows that EPS foam not only has good thermal insulation properties, but can also provide structural stability under specific conditions and reduce the impact of environmental changes on buildings.
The reason why the EPS foam layer can provide excellent thermal insulation effect is mainly because its internal structure contains a large number of tiny pores, which are tightly closed and connected to each other, forming an effective thermal insulation barrier. At the same time, the closed and foamed spherical molecular structure of EPS foam and the air trapped inside it act as a poor conductor of heat, working together to make EPS foam a lightweight, efficient, and environmentally friendly thermal insulation material.
How does the tiny pore structure of the EPS foam layer affect its thermal conductivity?
The influence of the tiny pore structure of the EPS foam layer on its thermal conductivity is mainly reflected in the following aspects:
- Porosity size and shape: The size and shape of pores directly affect the thermal conductivity of the material. Smaller pores can restrict the movement of gas molecules, thereby reducing the possibility of heat transfer through the pores, resulting in a lower thermal conductivity of the material. In addition, the shape of the pores will also affect its blocking effect on heat energy. Irregular or specific shaped pores may block the transfer of heat energy more effectively.
- Pore density: The density of pores is also an important factor affecting the thermal conductivity. A high density of pores means more space for filling with air or other gases, which typically have lower thermal conductivities, so the overall material's thermal conductivity is reduced.
- Type of gas in the cells: The type of gas contained in the cells also affects the thermal conductivity of the material. For example, cells containing a lower thermal conductivity gas (such as carbon dioxide) will have a lower thermal conductivity than cells containing a higher thermal conductivity gas (such as oxygen).
- Interaction of cells and polymer matrix: Cell structure not only affects the behavior of the gas inside, but also affects the response of the polymer matrix to external heat flow. The presence of cells increases the porosity of the material, which may change the thermal conduction path of the polymer matrix, thus affecting the overall thermal conductivity.
- Moisture absorption: The moisture content of the EPS foam layer has a significant impact on its thermal conductivity. The presence of moisture increases the thermal conductivity of the material because water is a good conductor of heat. For every 1% volume of water absorbed, the thermal conductivity will increase significantly.
The tiny pore structure of the EPS foam layer affects its thermal conductivity by controlling the size, shape, density of the pores, and the interaction between the type of gas in the cells and the polymer matrix. These factors work together to determine the thermal resistance performance of the EPS foam layer under different conditions.