Preparation of &lt;i&gt;p&lt;/i&gt;-Aramid Aerogels Using Supercritical CO&lt;sub&gt;2&lt;/sub&gt;

Shao, Zhenzong; Okubayashi, Satoko

doi:10.2115/fiber.70.233

Cited by 3 publications

(3 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[ 24 ] For example, Okubayashi et al. [ 25 ] split the macroscopic Kevlar fibers into ANFs by using a mixture of tetrabutylammonium fluoride and DMSO under a homogenization process, followed by incubating 24 h at 30 °C. Kotov et al.…”

Section: Introductionmentioning

confidence: 99%

“…[24] Particularly, since Kotov's pioneering work in 2011, the deprotonation process of macroscopic aramid fibers in alkali/dimethyl sulfoxide (DMSO) has been explored. [24] For example, Okubayashi et al [25] split the macroscopic Kevlar fibers into ANFs by using a mixture of tetrabutylammonium fluoride and DMSO under a homogenization process, followed by incubating 24 h at 30 °C. Kotov et al [26] prepared branched ANFs by partial ionizing of aramid chains in a 1-week hydrolysis process.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Visible Microfluidic Deprotonation for Aramid Nanofibers as Building Blocks of Cascade‐Microfluidic‐Processed Colloidal Aerogels

Ding,

Cheng,

Lyu

et al. 2024

Advanced Materials

View full text Add to dashboard Cite

Aramid nanofibers (ANFs) have played a significant role in fabricating advanced materials. However continuous and efficient preparation of homogeneous ANFs remains challenging. Herein, a microfluidic deprotonation approach is proposed for the first time to realize continuous, scalable, efficient, and uniform production of ANFs by virtue of large specific surface area, high mixing efficiency, strong heat transfer capacity, narrow residence time distribution, mild laminar‐flow process and amplification‐free effect of the microchannel reactor. By means of monitoring capabilities endowed by the high transparency of the microchannel, the kinetic exfoliation process of original aramid particles was in situ observed and the corresponding exfoliation mechanism was established quantificationally. The deprotonated time can be reduced from traditional several days to 7 minutes for the final colloidal dispersion due to the synergistic effect between enhanced local shearing/mixing and the rotational motion of aramid particles in microchannel revealed by numerical simulations. Furthermore, the cascade microfluidic processing approach was used to make various ANF colloidal aerogels including aerogel fibers, aerogel films and 3D printed aerogel articles. Comprehensive characterizations show that these cascade‐microfluidic‐processed colloidal aerogels have identical features as those prepared in batch‐style mode, revealing the versatile use value of these ANFs. This work achieves significant progress towards continuous and efficient production of ANFs, bringing about appreciable prospects for the practical application of ANF‐based materials and providing inspiration for exfoliating of any other nano‐building blocks.This article is protected by copyright. All rights reserved

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Visible Microfluidic Deprotonation for Aramid Nanofibers as Building Blocks of Cascade‐Microfluidic‐Processed Colloidal Aerogels

Ding,

Cheng,

Lyu

et al. 2024

Advanced Materials

View full text Add to dashboard Cite

show abstract

“…This fact can be crucial for PPTA AG manufacturing as a loose aerogel structure needs the separation of polymer chains. The main preparation method of PPTA AGs is the use of KOH/DMSO, NH 4 F/DMSO, or H 2 SO 4 /H 3 PO 4 systems to convert para-aramid fibers into aramid nanofibers (ANF) [21][22][23][24][25][26][27][28], followed by their gelation and supercritical drying (SCD) or freeze-drying procedure. In addition, an industrial-like procedure for PPTA synthesis from terephthaloyl chloride and aromatic diamines in N-methyl pyrrolidone (NMP) in the presence of calcium chloride is also used [29,30].…”

Section: Introductionmentioning

confidence: 99%

Highly Porous Para-Aramid Aerogel as a Heterogeneous Catalyst for Selective Hydrogenation of Unsaturated Organic Compounds

et al. 2023

View full text Add to dashboard Cite

A new para-aramid aerogel based on a polymer made by the reaction of terephthaloyl dichloride with 2-(4-aminophenyl)-1H-benzimidazol-5-amine (PABI) is introduced. The aerogel readily bound Pd (+2) ions and was used as a hydrogenation catalyst in some industrially actual reactions. The new material, which did not contain p-phenylenediamine moieties, was prepared in two form factors: bulk samples and spherical pellets of 700–900 μm in diameter. Aerogels were synthesized from 1% or 5% solutions of PABI in N,N-dimethylacetamide via gelation with acetone or isopropanol and had a density of 0.057 or 0.375 g/cm3 depending on the concentration of the starting PABI solution. The specific surface area of the obtained samples was 470 or 320 m2/g. Spherical pellets containing Pd were prepared from a solution of PdCl2 in PABI and were used as heterogeneous catalysts for the gas-phase hydrogenation of unsaturated organic compounds presenting the main types of industrially important substrates: olefins, acetylenes, aromatics, carbonyls, and nitriles. Catalytic hydrogenation of gaseous hexene-1, hexyne-3, cyclohexene, and acrylonitrile C=C bond proceeded with a 99% conversion at ambient pressure, but the catalyst failed to reduce acetone at 150 °C and benzene and ethyl acetate even at 200 °C. The only product of acrylonitrile hydrogenation was propionitrile. The prepared catalysts showed high selectivity, which is important for the chemistry of complex organic compounds.

show abstract

Ultrahigh-strength cellulose nanofiber foams via the synergy of freeze-casting and solvent exchange

Feng,

Chang,

Wang

et al. 2025

Carbohydrate Polymers

View full text Add to dashboard Cite

Preparation of <i>p</i>-Aramid Aerogels Using Supercritical CO<sub>2</sub>

Cited by 3 publications

References 13 publications

Visible Microfluidic Deprotonation for Aramid Nanofibers as Building Blocks of Cascade‐Microfluidic‐Processed Colloidal Aerogels

Visible Microfluidic Deprotonation for Aramid Nanofibers as Building Blocks of Cascade‐Microfluidic‐Processed Colloidal Aerogels

Highly Porous Para-Aramid Aerogel as a Heterogeneous Catalyst for Selective Hydrogenation of Unsaturated Organic Compounds

Ultrahigh-strength cellulose nanofiber foams via the synergy of freeze-casting and solvent exchange

Contact Info

Product

Resources

About