Abstract For polymer foams with low-density, the thermal radiation propagating through the foam still contributes significant to the total thermal transfer. It is very promising to enhance the absorption or reflection of IR radiation by the foam matrix. However, it is still a question which of the reflected infrared or absorbed infrared is more effective in reducing radiative thermal conductivity. In this work, we studied theoretically and experimentally the effectiveness to reduce the radiative thermal conductivity of polymer foams by reflection mode and absorption mode. The relationship between the optical parameters of foam and the heat radiation transmission in the foams was quantitatively investigated. It was found that, taking into account the re-emission, the radiative thermal conductivity was further reduced merely by increasing the absorption coefficient, but in theory it could continue to drop to zero by increasing the reflection fraction. Both the flake aluminum powder (FAP) that mainly reflects infrared and the flake graphite powder (FGP) that mainly absorbs infrared were added to the rigid cross-linked PVC (c-PVC) foam. The results demonstrated that the reduction of radiative thermal conductivity of the c-PVC foam with FAP was more significant than of the c-PVC foam with FGP. The experimental results were in good agreement with the theoretical prediction.

中文翻译：

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添加高反射红外遮光剂制备具有优异隔热性能的硬质交联PVC泡沫

摘要 对于低密度聚合物泡沫，通过泡沫传播的热辐射仍然对总热传递有重要贡献。增强泡沫基质对红外辐射的吸收或反射是非常有前途的。然而，反射红外线和吸收红外线中哪一个更有效地降低辐射热导率仍然是一个问题。在这项工作中，我们从理论和实验上研究了通过反射模式和吸收模式降低聚合物泡沫辐射热导率的有效性。定量研究了泡沫的光学参数与泡沫中热辐射透射率之间的关系。结果发现，考虑到再排放，仅仅通过增加吸收系数，辐射热导率会进一步降低，但理论上它可以通过增加反射率继续下降到零。将主要反射红外线的片状铝粉（FAP）和主要吸收红外线的片状石墨粉（FGP）都加入到硬质交联PVC（c-PVC）泡沫中。结果表明，含 FAP 的 c-PVC 泡沫的辐射热导率降低比含 FGP 的 c-PVC 泡沫更显着。实验结果与理论预测吻合较好。将主要反射红外线的片状铝粉（FAP）和主要吸收红外线的片状石墨粉（FGP）都加入到硬质交联PVC（c-PVC）泡沫中。结果表明，含 FAP 的 c-PVC 泡沫的辐射热导率降低比含 FGP 的 c-PVC 泡沫更显着。实验结果与理论预测非常吻合。将主要反射红外线的片状铝粉（FAP）和主要吸收红外线的片状石墨粉（FGP）都加入到硬质交联PVC（c-PVC）泡沫中。结果表明，含 FAP 的 c-PVC 泡沫的辐射热导率降低比含 FGP 的 c-PVC 泡沫更显着。实验结果与理论预测非常吻合。