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Solvent Effects on Tuning Pore Structures in Polyimide Aerogels
Langmuir ( IF 3.7 ) Pub Date : 2018-06-29 00:00:00 , DOI: 10.1021/acs.langmuir.8b01513 Nicholas Teo 1 , Sadhan C. Jana 1
Langmuir ( IF 3.7 ) Pub Date : 2018-06-29 00:00:00 , DOI: 10.1021/acs.langmuir.8b01513 Nicholas Teo 1 , Sadhan C. Jana 1
Affiliation
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This work evaluates the effects of solvents and a block copolymer surfactant on pore structures in polyimide aerogels synthesized via sol–gel reaction process. Specifically, cross-linked polyimide gel networks are synthesized in single or mixed solvents from a combination of dimethylformamide, N-methylpyrrolidone, and dimethylacetamide and supercritically dried to obtain aerogels. The bulk density, pore size, and mechanical properties of aerogels are determined. The results show that gel times are strongly dependent on the electron acceptance ability of the solvent system and concentration of the surfactant. At longer gel times, the polyimide strands coarsen and the pores in aerogel shift from predominantly mesoporous to macroporous state with corresponding reduction in compressive modulus. The block copolymer surfactant also slows down gelation and coarsens the polyimide strands but only weakly affects the compressive modulus of the aerogels.
中文翻译：
溶剂对聚酰亚胺气凝胶微孔结构的影响
这项工作评估了溶剂和嵌段共聚物表面活性剂对通过溶胶-凝胶反应过程合成的聚酰亚胺气凝胶中孔结构的影响。具体而言，交联的聚酰亚胺凝胶网络是在一种或两种溶剂中由二甲基甲酰胺，N的组合合成的-甲基吡咯烷酮和二甲基乙酰胺，超临界干燥，得到气凝胶。确定气凝胶的堆积密度，孔径和机械性能。结果表明，胶凝时间很大程度上取决于溶剂体系的电子接受能力和表面活性剂的浓度。在更长的凝胶时间下，聚酰亚胺链变粗，气凝胶中的孔从主要为中孔状态转变为大孔状态，并相应降低了压缩模量。嵌段共聚物表面活性剂也减慢了凝胶化作用，并使聚酰亚胺链变粗，但仅微弱地影响了气凝胶的压缩模量。
更新日期：2018-06-29
中文翻译：
溶剂对聚酰亚胺气凝胶微孔结构的影响
这项工作评估了溶剂和嵌段共聚物表面活性剂对通过溶胶-凝胶反应过程合成的聚酰亚胺气凝胶中孔结构的影响。具体而言，交联的聚酰亚胺凝胶网络是在一种或两种溶剂中由二甲基甲酰胺，N的组合合成的-甲基吡咯烷酮和二甲基乙酰胺，超临界干燥，得到气凝胶。确定气凝胶的堆积密度，孔径和机械性能。结果表明，胶凝时间很大程度上取决于溶剂体系的电子接受能力和表面活性剂的浓度。在更长的凝胶时间下，聚酰亚胺链变粗，气凝胶中的孔从主要为中孔状态转变为大孔状态，并相应降低了压缩模量。嵌段共聚物表面活性剂也减慢了凝胶化作用，并使聚酰亚胺链变粗，但仅微弱地影响了气凝胶的压缩模量。
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