One-step room-temperature synthesis of fibrous polyimide aerogels from anhydrides and isocyanates and conversion to isomorphic carbons

Chidambareswarapattar, Chakkaravarthy; Larimore, Zachary; Sotiriou‐Leventis, Chariklia; Mang, Joseph T.; Leventis, Nicholas

doi:10.1039/c0jm01844a

Cited by 139 publications

(103 citation statements)

References 59 publications

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“…30 But polyimide aerogel made by this way exhibited much weaker mechanical strength than chemically identical polyimide aerogel prepared from a dianhydride and a diamine. Then, Leventis et al prepared cross-linked polyimide aerogels synthesized from dianhydrides and triisocyanates.…”

Section: ■ Introductionmentioning

confidence: 98%

Preparation and Characterization of Highly Cross-Linked Polyimide Aerogels Based on Polyimide Containing Trimethoxysilane Side Groups

2014

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In this study, highly cross-linked and completely imidized polyimide aerogels were prepared from polyimide containing trimethoxysilane side groups, which was obtained as the condensation product of polyimide containing acid chloride side groups and 3-aminopropyltrimethoxysilane. After adding water and acid catalyst, the trimethoxysilane side groups hydrolyzed and condensed one another, and a continuous increase in the complex viscosities of the polyimide solutions with time was observed. The formed polyimide gels were dried by freeze-drying from tert-butyl alcohol to obtain polyimide aerogels, which consisted of a three-dimensional network of polyimide fibers tangled together. By varying the solution concentration of the polyimide containing trimethoxysilane side groups, polyimide aerogels with different densities (ranging from 0.19 to 0.42 g/cm(3)) were obtained. The resulting polyimide aerogels had small pore diameter (ranging from 20.7 to 58.3 nm), high surface area (ranging from 310 to 344 m(2)/g), high 5% weight loss temperature in air (at about 440 °C), and an excellent mechanical property. In addition, the glass transition temperature (349 °C) of the polyimide aerogels was much higher than that (210 °C) of the corresponding linear polyimide. So, even after being heated at 300 °C for 30 min, the porous structure of the polyimide aerogels was not completely destroyed.

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Section: ■ Introductionmentioning

confidence: 98%

Preparation and Characterization of Highly Cross-Linked Polyimide Aerogels Based on Polyimide Containing Trimethoxysilane Side Groups

2014

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“…Polyimide aerogels (PIAs, either in a linear [18] or crosslinked structure [19e21]), inheriting the excellent thermal stability from polyimides and the low densities of aerogels, are especially promising. Nevertheless, the development of a CNT/polymer aerogel composite fiber has not been reported so far.…”

Section: Introductionmentioning

confidence: 99%

Formation mechanisms and morphological effects on multi-properties of carbon nanotube fibers and their polyimide aerogel-coated composites

Liu

Tran

Fan

et al. 2015

Composites Science and Technology

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“…32 In this study, the incorporation of NB-R with a different substituent group might distort further growth of the primary PDCPD fibrils by either (i) decreasing the number of reactive sites (i.e., the crosslinking) at the surface or (ii) sterically hindering inter-particle crosslinking, as has been proposed for polyimide aerogels from anhydride and isocyanates. 33 Formation of many shorter fiber strands with a good solubility and/or a better chain mobility makes it possible to form more entangled morphologies, and it could explain a transformation in the pore size and morphologies as well as the higher moduli and viscosity at the gel point of in the copolymer gel systems. Considering the effect of different crosslinkers, the unique fibril structure of primary particles seems to be attributed to the molecular structure of PDCPD and its inter-molecular interaction.…”

Section: Gmentioning

confidence: 99%

“…The distinct features in P(DCPD-r-NB-R) copolymer networks are changes in length of fiber strands, and pore sizes and morphologies surrounded by the strands. Leventis et al [31][32][33] explained the formation of organic (polymer) aerogels by (i) crosslinking at the molecular level resulting in early phase separation of small surface-reactive particles and (ii) subsequent inter-particle crosslinking that improves mechanical properties of the materials. Based on those principles, long PDCPD strands with a length of hundreds of nm up to a few m would be the combination of primary and secondary particles like in polyurea aerogels.…”

Section: Gmentioning

confidence: 99%

Exploration of the versatility of ring opening metathesis polymerization: an approach for gaining access to low density polymeric aerogels

et al. 2012

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We report the preparation of low density polymeric aerogels using the ring opening metathesis polymerization (ROMP) approach to copolymerize dicyclopentadiene (DCPD) with norbornene-based monomers (NB-R) employing a first generation Grubbs' Ruthenium-based catalyst. The ROMP approach offers an attractive synthetic method that enables the fabrication of low-density (0.02-0.05 g/cm 3 ), uniform thickness aerogel coatings on non-planar substrates. First, we explore the effect of crosslinking in the polymer backbone on the uniformity of the gel coatings formed under shear by either adding a multi-norbornene based crosslinker (NB n -R) to increase, or linear NB-R co-monomers to decrease, the degree of crosslinking, respectively. We observed that adding linear monomers dramatically improved the uniformity of the gel films which we attribute to cross-linking induced changes in the rheological properties at the gel point. Second, the copolymerization of DCPD and NB-R with a different pendant group also causes a significant change in the morphology of PDCPD-based aerogels by modifying lengths of strands in the fibrous polymer network. The effect of NB-R addition on the pore structure of the aerogels is discussed in context of a molecular and interparticle crosslinking model. Finally, (bis)iodo-norbornene was synthesized to demonstrate the feasibility to fabricate functionalized aerogels by using our copolymerization approach. Our results highlight the potential of the ROMP-based copolymerization approach as a facile and versatile route to functionalized low density polymeric aerogels.

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One-step room-temperature synthesis of fibrous polyimide aerogels from anhydrides and isocyanates and conversion to isomorphic carbons

Cited by 139 publications

References 59 publications

Preparation and Characterization of Highly Cross-Linked Polyimide Aerogels Based on Polyimide Containing Trimethoxysilane Side Groups

Preparation and Characterization of Highly Cross-Linked Polyimide Aerogels Based on Polyimide Containing Trimethoxysilane Side Groups

Formation mechanisms and morphological effects on multi-properties of carbon nanotube fibers and their polyimide aerogel-coated composites

Exploration of the versatility of ring opening metathesis polymerization: an approach for gaining access to low density polymeric aerogels

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