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. 2023 Feb 7;39(5):1804-1814.
doi: 10.1021/acs.langmuir.2c02696. Epub 2023 Jan 27.

Macroporous Polyimide Aerogels: A Comparison between Powder Microparticles Synthesized via Wet Gel Grinding and Emulsion Processes

Shima Dayarian  1 , Hojat Majedi Far  2 , Liu Yang  1
Affiliations

Macroporous Polyimide Aerogels: A Comparison between Powder Microparticles Synthesized via Wet Gel Grinding and Emulsion Processes

Shima Dayarian et al. Langmuir. .

Abstract

It is noteworthy to mention that synthesizing the polyimide aerogel powder, which is carried out in this study, benefits from two advantages: (i) the powder particles can be used for some specific applications where the monolith is not suitable and (ii) there is a possibility to investigate how a polyimide aerogel monolith can be made through the polyimide powder to reduce its cost and cycle time. In this study, two straightforward methods, wet gel grinding and emulsion, are introduced to prepare polyimide aerogel powders using ambient pressure drying. The microscopic properties of interest, including skeletal and porous structures, microparticle size and assembly, combined with macroscopic properties such as thermal stabilities and conductivities (0.039 W/m·K), confirm that the fabricated microparticles with a size in the range of 7-20 μm and porosity in the range of 65-85% are thermally stable up to 500 °C.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Scheme 1
Scheme 1. Schematic Representation of WGG and EM Synthetic Processes Used in This Study for the Preparation of PI Aerogel Microparticles
PAA: polyamic acid (resin); WGG: wet gel grinding; EM: emulsion; PI-WGG: polyimide aerogel powders by WGG; PI-EM: polyimide aerogel powders by EM.
Scheme 2
Scheme 2. Synthesis of PAA and PI Aerogel from Amines (DMB, ODA, TAPOB) and Anhydrides (BPDA, PA) and Catalyzed with 2-MI
Figure 1
Figure 1
Particle size distribution for PI-WGG powders at different dilution ratios.
Figure 2
Figure 2
SEM for PI-WGG powders with DMSO/PAA ratios of (a) 0.0, (b) 0.5, (c) 1.0, and (d) 1.5.
Figure 3
Figure 3
Particle size distribution for PI-EM powders at different dilution ratios.
Figure 4
Figure 4
SEM images for PI-EM powders with DMSO/PAA ratios of (a) 0.0, (b) 0.5, (c) 1.0, and (d) 1.5.
Figure 5
Figure 5
Pore size distributions of PI-WGG powders were measured using (a) N2 sorption and (b) MIP.
Figure 6
Figure 6
Pore size distributions of PI-EM powders were measured by (a) N2 sorption and (b) MIP.
Figure 7
Figure 7
Porosity–density profiles for PI-WGG and PI-EM powders.
Figure 8
Figure 8
% Weight as a function of temperature for (a) PI-WGG and (b) PI-EM powders.
Figure 9
Figure 9
Thermal conductivity–density profiles for (a) PI-WGG and (b) PI-EM powders.
Figure 10
Figure 10
Correlation of thermal conductivity and dilution ratio for (a) PI-WGG and (b) PI-EM.
Figure 11
Figure 11
Correlation of thermal conductivity and pore size for PI-EM.
See this image and copyright information in PMC

References

    1. Lee D. H.; Jo M. J.; Han S. W.; Yu S.; Park H. Polyimide aerogel with controlled porosity: Solvent-induced synergistic pore development during solvent exchange process. Polymer 2020, 205, 122879 10.1016/j.polymer.2020.122879. - DOI
    1. Qiao S.; Kang S.; Hu Z.; Yu J.; Wang Y.; Zhu J. Moisture-resistance, mechanical and thermal properties of polyimide aerogels. J. Porous Mater. 2020, 27, 237–247. 10.1007/s10934-019-00801-2. - DOI
    1. Hou X.; Mao Y.; Zhang R.; Fang D. Super-flexible polyimide nanofiber cross-linked polyimide aerogel membranes for high efficient flexible thermal protection. Chem. Eng. J. 2021, 417, 129341 10.1016/j.cej.2021.129341. - DOI
    1. Zhu Z.; Yao H.; Dong J.; Qian Z.; Dong W.; Long W. High-mechanical-strength polyimide aerogels cross-linked with 4, 4′-oxydianiline-functionalized carbon nanotubes. Carbon 2019, 144, 24–31. 10.1016/j.carbon.2018.11.057. - DOI
    1. Shi B.; Ma B.; Wang Ch.; He H.; Qu L.; Xu B.; Chen Y. Fabrication and applications of polyimide nano-aerogels. Composites, Part A 2021, 143, 106283 10.1016/j.compositesa.2021.106283. - DOI