Mechanical and thermal properties of porous polyimide monoliths crosslinked with aromatic and aliphatic triamines
Mechanical and thermal properties of porous polyimide monoliths crosslinked with aromatic and aliphatic triamines
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DOI：
10.1007/s10971-022-05843-8
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发表时间：
2022-05
影响因子：
2.5
通讯作者：
Mitsuhiro Ishida;Yutaro Sashiyama;H. Akamatsu;Katsuro Hayashi;K. Nakanishi;George Hasegawa
中科院分区：
文献类型：
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作者：
Mitsuhiro Ishida;Yutaro Sashiyama;H. Akamatsu;Katsuro Hayashi;K. Nakanishi;George Hasegawa
隔热材料对于有效利用热能具有重要意义。多孔有机泡沫由于其低导热性和低成本的大规模生产率而被广泛用于此目的。然而，有机聚合物的热稳定性较差，限制了它们在低温范围内（通常< 150°C）的可用性。在本文中，我们展示了多孔聚酰胺酸（PAA）干凝胶的一锅溶胶凝胶合成及其通过热酰亚胺化转化为多孔聚酰亚胺（PI）整体。 PAA 网络与芳香族或脂肪族三胺交联，以及通过旋节线分解定制的双连续多孔形态，允许在环境压力下蒸发干燥，以获得低密度 PAA 干凝胶，而不会明显收缩。与用脂肪族三胺制备的多孔PI整体材料相比，芳香族交联剂产生的多孔PI整体材料具有更高的孔隙率和柔性特征。另一方面，基于脂肪族交联剂的多孔PI整体材料由于更硬的机械性能而具有稍高的热稳定性。耐久性测试结果验证了多孔 PI 绝热体可在高达 ~450°C 的空气中短期使用，并可长期在高达 ~350°C 的空气中使用。图形摘要
Thermal insulating materials are of importance for efficient and effective use of heat energy. Porous organic foams are widely employed for this purpose owing to their low thermal conductivity and mass productivity at low cost. However, the poor thermal stability of organic polymers limits their availability within a low temperature range (typically, < 150 °C). In this paper, we demonstrate the one-pot sol–gel synthesis of porous poly(amic acid) (PAA) xerogels and their conversion to porous polyimide (PI) monoliths by thermal imidization. The PAA networks crosslinked with either aromatic or aliphatic triamine and the bicontinuous porous morphology tailored via spinodal decomposition allow the evaporative drying at ambient pressure to obtain low-density PAA xerogels without significant shrinkage. The aromatic crosslinker yields the porous PI monoliths with higher porosity and flexible feature as compared with those prepared with the aliphatic triamine. On the other hand, the porous PI monolith based on the aliphatic crosslinker possesses slightly higher thermal stability owing to the stiffer mechanical property. The durability test results verify the porous PI thermal insulators are available in air at up to ~450 °C for a short period and up to ~350 °C for a long term.Graphical abstract