Thermal conductivity of porous polymer materials considering pore special-shape and anisotropy

The thermal insulation performance of porous polymer material is greatly affected by the pore structure. However, the effect of pore special-shape on the thermophysical properties of porous polymer material has not been considered. In this study, the effects of pore shape, overlap, and anisotropy are evaluated at the same time. The results show that the special-shaped pore had a better effect on the thermal insulation performance than common pores. The difference in thermal insulation performance caused by pore shape is increased with the gas content. The thermal insulation performance increases with the pore overlap only when the pores are overlapped in the direction vertical to heat flux. The common and special-shaped pores have different overlap probabilities in the same direction. The special-shaped pore is more sensitive to the directional angle than common pore and has significant anisotropy. Meanwhile, the pore anisotropy is affected by the pore overlap. The manufacture of porous polymer material must pay attention to the directional angle of the special-shaped pore and heat flux direction.