Yakushin Vladimir, Dhalivala Vanesa, Vevere Laima, Cabulis Ugis
Latvian State Institute of Wood Chemistry, Dzerbenes Street 27, LV-1006 Riga, Latvia.
Polymers (Basel). 2025 Jun 16;17(12):1669. doi: 10.3390/polym17121669.
This study explores how production technology influences spray-applied rigid polyurethane (PUR) foam insulation's cryogenic performance. In cryogenic applications such as liquid gas storage, insulation must minimise heat transfer and resist moisture ingress under severe thermal gradients. Experimental aluminium vessels were insulated with PUR foam of varying thicknesses and surface conditions-rough, machined smooth, and with a urea-based protective coating-and then tested using dynamic boil-off of liquid nitrogen (LN). Foam properties, including adhesion, mechanical strength, thermal expansion, thermal conductivity, and closed-cell content, were evaluated. The results revealed that thicker insulation reduced both effective thermal conductivity and moisture uptake. Although the urea-coated vessel showed minimal water absorption, the coating increased overall thermal conductivity due to its heat conduction and condensation behaviour. Moisture was primarily absorbed near the foam surface, and no cumulative effects were observed during repeated tests. The effective thermal conductivity was determined by interpolating boil-off data, confirming that insulation performance strongly depends on thickness, surface condition, and environmental humidity. These findings provide valuable guidance for the design and application of PUR foam insulation in cryogenic environments.
本研究探讨了生产工艺如何影响喷涂硬质聚氨酯（PUR）泡沫保温材料的低温性能。在诸如液化气储存等低温应用中，保温材料必须在严苛的热梯度条件下将热传递降至最低，并防止水分侵入。用不同厚度和表面条件（粗糙、机械加工光滑以及带有脲基保护涂层）的PUR泡沫对实验用铝制容器进行保温，然后通过液氮（LN）的动态蒸发进行测试。对泡沫的性能进行了评估，包括附着力、机械强度、热膨胀、热导率和闭孔率。结果表明，较厚的保温层可降低有效热导率和吸水量。尽管涂有脲基涂层的容器吸水率最低，但由于涂层的热传导和冷凝行为，其整体热导率有所增加。水分主要在泡沫表面附近被吸收，在重复测试过程中未观察到累积效应。通过对蒸发数据进行插值来确定有效热导率，证实保温性能很大程度上取决于厚度、表面条件和环境湿度。这些发现为PUR泡沫保温材料在低温环境中的设计和应用提供了有价值的指导。
