Synthesis of Flexible Polyamide Aerogels Cross-Linked with a Tri-Isocyanate

• Published in: Gels Vol. 10; no. 8; p. 519
• Main Authors: Scheiman, Daniel A., Guo, Haiquan, Oosterbaan, Katherine J., McCorkle, Linda, Nguyen, Baochau N.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 07.08.2024; MDPI
• Subjects: Crosslinking; density vs. modulus; flexible polyamide aerogel; Hydrocarbons; Isocyanates; mesoporous; NMR; Nuclear magnetic resonance; Physical properties; Polyamide resins; Polyamides; Polymers; Porosity; Silica aerogels; Solar energy; Spectrum analysis; thermal stability; tri-isocyanate cross-linker
• ISSN: 2310-2861; 2310-2861
• DOI: 10.3390/gels10080519

A new series of flexible polyamide (PA) aerogels was synthesized using terephthaloyl chloride (TPC), 2,2′-dimethylbenzidine (DMBZ) and cross-linked with an inexpensive, commercially available tri-isocyanate (Desmodur N3300A) at polymer concentrations of 6–8 wt.% total solids and repeating units, n, from 30 to 60. The cross-linked DMBZ-based polyamide aerogels obtained, after supercritically drying using liquid CO2, had shrinkages of 19–27% with densities ranging from 0.12 g/cm3 to 0.22 g/cm3, porosity and surface areas up to 91% and 309 m2/g, respectively, and modulus values ranging from 20.6 to 109 MPa. Evidence suggests that a higher flexibility could be achieved using DMBZ in the polyamide backbone with N3300A as a cross-linker, when compared to previously reported TPC-mPDA-BTC PA aerogels, N3300A-polyimide aerogels, and N3300-reinforced silica aerogels.