Influences of different imidization conditions on polyimide fiber properties and structure

Wang, Ziqi; Zhang, Junying; Niu, Hongqing; Wu, Dezhen; Zhang, Mingjie; Han, En‐Hou; Sheng, Jiping; Sun, Xiao‐Guang; Fan, Chao

doi:10.1002/app.51189

Cited by 9 publications

(8 citation statements)

References 39 publications

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“…The influences of the thermal treatment temperature on the structure and properties of the PI fibers were also studied, both of the molecular chain relaxation and the evolution of aligned microvoids induced by post-thermal treatment resulted in the change in tensile modulus. [28][29][30][31] Wang et al [32] investigated influences of different imidization conditions on PI fiber properties and structure, the results indicated that the imidization conditions affected the mechanical properties of the fiber by affecting the hydrogen-bond associations and the microvoids structure.…”

Section: Doi: 101002/mats202100081mentioning

confidence: 99%

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Clarifying the Effect of Drafting Conditions on Structure and Properties of Polyimide Fibers at Molecular Dynamic Level

Lin

Jiang

et al. 2022

Macro Theory & Simulations

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A series of pyromellitic dianhydride/4,4′-oxydianiline orientation models are constructed by molecular dynamic simulation, and the effects of drafting rate, drafting temperature, and imidization degree on structure and mechanical properties of polyimide fibers are studied. The high drafting rate is conducive to the orientation of molecular chains along the axis, but it is easy to form defects inside of the fibers, so the tensile modulus of the orientation model at a draft ratio of 6 is decreased from 21.6 to 9.8 GPa with increasing the drafting rate. The high drafting temperature reduced the intermolecular interaction, which is not conducive to the orientation of the molecular chain along the axis, the tensile modulus of orientation models at a draft ratio of 6 decreased from 21.6 to 11.7 GPa with the drafting temperature increasing from 298 to 598 K. Besides, the molecular chains of PI fibers drawn from the high imidization degree are arranged more regularly along the axis due to the PI units have greater rigidity than the polyamic acid units. This work provides guidance for the optimization of PI fibers heat-drafting process from the perspective of molecular chain conformational evolution.

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Section: Doi: 101002/mats202100081mentioning

confidence: 99%

“…[ 28–31 ] Wang et al. [ 32 ] investigated influences of different imidization conditions on PI fiber properties and structure, the results indicated that the imidization conditions affected the mechanical properties of the fiber by affecting the hydrogen‐bond associations and the microvoids structure.…”

Section: Introductionmentioning

confidence: 99%

Clarifying the Effect of Drafting Conditions on Structure and Properties of Polyimide Fibers at Molecular Dynamic Level

Lin

Jiang

et al. 2022

Macro Theory & Simulations

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“…The density of polymer materials is far lower than that of metals and ceramics, and with the development of material technology, their other properties have also been greatly improved. Among these polymer materials, polyimide (PI) film materials have outstanding properties [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ]: low density, high mechanical properties, great thermal stability, radiation resistance, corrosion resistance, excellent dielectric properties, and so on. Therefore, PI films can be used in microelectronics, aerospace, and other fields [ 9 , 10 , 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

Carboxylated Carbon Nanotube/Polyimide Films with Low Thermal Expansion Coefficient and Excellent Mechanical Properties

et al. 2022

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Polyimide (PI) films with excellent heat resistance and outstanding mechanical properties have been widely researched in microelectronics and aerospace fields. However, most PI films can only be used under ordinary conditions due to their instability of dimension. The fabrication of multifunctional PI films for harsh conditions is still a challenge. Herein, flexible, low coefficient of thermal expansion (CTE) and improved mechanical properties films modified by carboxylated carbon nanotube (C-CNT) were fabricated. Acid treatment was adapted to adjust the surface characteristics by using a mixture of concentrated H2SO4/HNO3 solution to introduce carboxyl groups on the surface and improve the interfacial performance between the CNT and matrix. Moreover, different C-CNT concentrations of 0, 1, 3, 5, 7, and 9 wt.% were synthesized to use for the PI film fabrication. The results demonstrated that the 9 wt.% and 5 wt.% C-CNT/PI films possessed the lowest CTE value and the highest mechanical properties. In addition, the thermal stability of the C-CNT/PI films was improved, making them promising applications in precise and harsh environments.

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“…29,30 In previous work, some aromatic PIs and poly(ether imide)s containing di-and triarylimidazolyl units into the polymer backbone or as bulky pendant groups have been reported. [31][32][33][34][35][36][37][38][39] In this paper, with an aim to develop high performance and processable PIs, a new kind of unsymmetrical diamine containing tetraarylimidazolyl and trifluoromethyl groups, 1,2diphenyl-4,5-bis(4-trifluoromethylphenyl)-1H-imidazole, has been synthesized successfully. Meanwhile, a new series of fluorinated imidazolyl-containing PIs were synthesized derived from the resulting diamine monomer.…”

Section: Introductionmentioning

confidence: 99%

New fluorinated polyimides based on 1,2-bis(4-aminophenyl)-4,5-bis(4-trifluoromethylphenyl)-1H-imidazole

Chen

Zhi-bin²,

Liu

et al. 2022

High Performance Polymers

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A new aromatic unsymmetrical diamine containing imidazolyl and trifluoromethyl groups, 1,2-bis(4-aminophenyl)-4,5-bis(4-trifluoromethylphenyl)-1H-imidazole was synthesized. A series of novel fluorinated polyimides (PIs) were prepared by polycondensation of this diamine monomer with various aromatic dianhydrides via one-step process. The resulting PIs bearing inherent viscosities of 0.45–0.61 dL/g were amorphous and readily soluble in organic polar solvents such as NMP, DMF, DMAc, THF, and CHCl3. These new PIs exhibited good thermal stability with 10% weight loss temperatures of 530–560°C and char yields of 61–65% at 800°C in nitrogen, as well as good flame retardancy with limited oxygen index value of 40.6–42.8, and outstanding hydrophobicity with the contact angle of 85.2–93.5°. Meanwhile, all the obtained PIs exhibited low water uptake of 0.30–0.53%, strong UV-vis absorption in the range of 267–310 nm in DMF solution, and their films presented high optical transparency with a cut-off wavelength in the 355–392 nm range. Except for the PI film derived from pyromellitic dianhydride, the other PI films had the tensile strength in the range of 53.2–74.1 MPa, elongation at breakage of 6–15%, and tensile modulus of 1.0–1.5 GPa, respectively.

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Influences of different imidization conditions on polyimide fiber properties and structure

Cited by 9 publications

References 39 publications

Clarifying the Effect of Drafting Conditions on Structure and Properties of Polyimide Fibers at Molecular Dynamic Level

Clarifying the Effect of Drafting Conditions on Structure and Properties of Polyimide Fibers at Molecular Dynamic Level

Carboxylated Carbon Nanotube/Polyimide Films with Low Thermal Expansion Coefficient and Excellent Mechanical Properties

New fluorinated polyimides based on 1,2-bis(4-aminophenyl)-4,5-bis(4-trifluoromethylphenyl)-1H-imidazole

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