Investigation of the properties and structure of semi-rigid closed-cellular polyimide foams with different diamine structures

Ni, Long; Luo, Yinfu; Peng, Xionghou; Zhou, Shengtai; Zou, Huawei; Liang, Mei

doi:10.1016/j.polymer.2021.123957

Cited by 21 publications

(17 citation statements)

References 49 publications

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“…However, PIF BTDA-DMBZ exhibited the lowest T 5% that was ascribed to the steric hindrance effect of the neighboring methyl group in the molecular chain. [50] Figure 7c,c' shows that the PIFs presented a similar degradation trend in the air atmosphere. The presence of oxygen exacerbated the pyrolysis of polymer chains, thereby resulting in a decrease of T 5% and a significant drop of R 800 when compared with those measured under the N 2 atmosphere.…”

Section: Thermal Performancementioning

confidence: 63%

“…However, PIF BTDA‐DMBZ exhibited the lowest T 5% that was ascribed to the steric hindrance effect of the neighboring methyl group in the molecular chain. [ 50 ]…”

Section: Resultsmentioning

confidence: 99%

“…And it could also be concluded that the thermal stability of PIFs was primarily affected by the molecular structure. [ 50 ]…”

Section: Resultsmentioning

confidence: 99%

“…And it could also be concluded that the thermal stability of PIFs was primarily affected by the molecular structure. [50] The glass transition temperatures (T g ) of PIFs with different molecular chain structures were assessed by DMA and DSC 8a, the values of T g for PIF BTDA-ODA , PIF BTDA-MDA , and PIF BTDA-DMBZ were 297.6, 305.2, and 348.2 °C, respectively. This indicated that the prepared PIFs demonstrated excellent heat resistance, which was suitable to be used in high temperature thermal insulation areas.…”

Section: Thermal Performancementioning

confidence: 99%

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Combining Microwave‐Assisted Foaming and Post Curing Process to Prepare Lightweight Flexible Polyimide Foams for Thermal Insulation Applications

Luo

Qiu

et al. 2022

Macro Materials & Eng

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Lightweight flexible polyimide foams (PIFs) with different rigid‐flexible molecular structure networks are prepared by microwave‐assisted foaming of polyester ammonium salt (PEAS) precursor powders, followed by post curing process to complete final imidization. The optimum foaming temperatures of PEAS precursors range from 85 to 135 °C, and the melting rate of PEAS is adjusted to meet the volatile releasing rate to fabricate PIFs. Results show that PIFs with nearly fully open cell rate (99.99%), micron pore sizes (400–500 µm), and micro/nano multiscale structures exhibit excellent mechanical flexibility and elasticity. The prepared PIFs demonstrate exceptional thermal stability and heat resistance in both dynamic and static environments. The PIFs possess low thermal conductivity and superior thermal insulation properties that demonstrate potential applications in high‐tech fields such as aerospace, marine use, and microelectronics among others.

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Section: Thermal Performancementioning

confidence: 63%

“…However, PIF BTDA‐DMBZ exhibited the lowest T 5% that was ascribed to the steric hindrance effect of the neighboring methyl group in the molecular chain. [ 50 ]…”

Section: Resultsmentioning

confidence: 99%

“…And it could also be concluded that the thermal stability of PIFs was primarily affected by the molecular structure. [ 50 ]…”

Section: Resultsmentioning

confidence: 99%

Section: Thermal Performancementioning

confidence: 99%

See 2 more Smart Citations

Combining Microwave‐Assisted Foaming and Post Curing Process to Prepare Lightweight Flexible Polyimide Foams for Thermal Insulation Applications

Luo

Qiu

et al. 2022

Macro Materials & Eng

Self Cite

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“…Thus, it is believed that PI foams can be considered as a good candidate for preparing the carbon foams. The methods for preparing PI foams include polyamic acid foaming, polyester ammonium salt precursor foaming, microsphere foaming and isocyanate-based foaming method [36]. The isocyanate-based foaming method is simple and easily implemented since it uses carbon dioxide that produced in situ as the foaming agent [37,38].…”

Section: -Bonded Carbonmentioning

confidence: 99%

Carbonization of Graphene-Doped Isocyanate-Based Polyimide Foams to Achieve Carbon Foams with Excellent Electromagnetic Interference Shielding Performance

et al. 2021

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Lightweight carbon foams with excellent electromagnetic interference (EMI) shielding performance were prepared by carbonization process, using isocyanate-based polyimide foams as carbon precursors. The influence of carbonization temperature and graphene-doping on the morphological, electrical and EMI shielding effectiveness (SE) of corresponding carbon foams was studied in detail. Results showed that the addition of graphene was beneficial to the improvement of electrical conductivity and EMI shielding performance of carbon foams. The electrical conductivity of carbon foams increased with the carbonization temperature which was related to the increase of graphitization degree. Collapse of foam cells was observed at higher carbonization temperatures, which was detrimental to the overall EMI SE. The optimal carbonization temperature was found at 1100 °C and the carbon foams obtained from 0.5 wt% graphene-doped foams exhibited a specific EMI SE of 2886 dB/(g/cm3), which shows potential applications in fields such as aerospace, aeronautics and electronics.

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Ultra‐light fluorinated polyimide foams with excellent thermal insulation, low dielectric loss and high heat resistance

Jia,

Sun,

Zang

et al. 2024

J of Applied Polymer Sci

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High efficiency thermal insulation materials are highly desirable in aerospace industry, whereas combining low density and low thermal conductivity of thermal insulation materials still remains a challenge. In this work, a series of fluorinated polyimide foams (PIFs) based on 4,4‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA) were successfully prepared by microwave‐assisted powder foaming. The modification of fluorination decreased the melt strength while simultaneously enhanced the thermal properties of fluorinated PIFs through the high bonding energy of CF bond. Thus, fluorinated PIFs exhibited one of the lowest densities of reported PIFs, among them, the density of PIF6FDA‐DMBZ was as low as 9.34 kg m−3. The glass transition temperature of all fluorinated PIFs was greater than 295°C. Microwave‐assisted foaming optimized the cell structure effectively, resulting in the thermal conductivity of PIF6FDA‐ODA as low as 0.029 W m−1 K−1. The incorporation of hexafluoroisopropylidene groups reduced the polarization and enhanced the free volume of fluorinated PIFs, leading to hydrophobic characteristics (CA >105°) and ultra‐low dielectric loss properties (tan δ <0.001 at 20 GHz). PIF6FDA‐ODA demonstrated the most excellent comprehensive performance. The excellent comprehensive performance of fluorinated PIFs indicated their potential application as thermal insulation and wave‐transparent materials in aerospace, railway, and shipbuilding industries.

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Investigation of the properties and structure of semi-rigid closed-cellular polyimide foams with different diamine structures

Cited by 21 publications

References 49 publications

Combining Microwave‐Assisted Foaming and Post Curing Process to Prepare Lightweight Flexible Polyimide Foams for Thermal Insulation Applications

Combining Microwave‐Assisted Foaming and Post Curing Process to Prepare Lightweight Flexible Polyimide Foams for Thermal Insulation Applications

Carbonization of Graphene-Doped Isocyanate-Based Polyimide Foams to Achieve Carbon Foams with Excellent Electromagnetic Interference Shielding Performance

Ultra‐light fluorinated polyimide foams with excellent thermal insulation, low dielectric loss and high heat resistance

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