High thermally stable thermosetting polyimides derived from a carborane-containing tetramine

Wu, Yuane; Chen, Feng; Yang, Jiping; Gong, Chen

doi:10.1177/0954008318779429

Cited by 11 publications

(9 citation statements)

References 30 publications

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“…34 After thermal-oxidative aging, the composite had a T g of 252°C and a T gmod of 215°C, both increased by the higher aging temperature of 190°C, which may accelerate the physical aging and postcure rate of the material. 35 The tan δ peak for the thermal-oxidative aged composite can be accordingly observed in Figure 4(b) to shift toward a higher temperature. 31 This indicates that the T800 carbon fiber–epoxy composite material evaluated in this study has good resistance to aging.…”

Section: Resultsmentioning

confidence: 89%

Effects of aging process and testing temperature on the open-hole compressive properties of a carbon fiber composite

et al. 2020

High Performance Polymers

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The properties of T800 carbon fiber–epoxy composite specimens with a hole were studied in terms of mass change, scanning electron microscopy, glass transition temperature ( T g), heat-resistant temperature, Fourier-transform infrared (FTIR) spectroscopy, open-hole compressive strength at different temperatures, and stereomicroscopic observations after being subjected to hygrothermal aging and thermal-oxidative aging processes. FTIR spectra indicated that after hygrothermal aging at 70°C and 85% relative humidity (RH), chemical aging did not occur, whereas after thermal-oxidative aging at 190°C, the specimens exhibited chemical aging. The unaged specimens had a T g of 229°C and an extreme heat-resistant temperature T gmod of 184°C; after hygrothermal aging, the specimens had a T g and T gmod of 207°C and 143°C, respectively; and after thermal-oxidative aging, the specimens had a T g and T gmod of 252°C and 215°C, respectively. The effects of temperature on open-hole compressive strength were evaluated at room temperature of 23°C, 50°C, 100°C, 150°C, and 200°C. The compressive strengths of the specimens decreased after aging and with the increasing test temperature. At the highest test temperature, the unaged specimens, hygrothermal-aged, and thermal-oxidative-aged specimens retained over 73.7%, 65.5%, and 67.9%, respectively, of their compressive strength. Thus, the T800 carbon fiber–epoxy composite evaluated in this study exhibited good resistance to the effects of aging and high temperature. These results should be beneficial to the understanding of the long-term performance of composites.

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Section: Resultsmentioning

confidence: 89%

Effects of aging process and testing temperature on the open-hole compressive properties of a carbon fiber composite

et al. 2020

High Performance Polymers

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“…21 The DSC results indicated that the novel method had some effect on the heat resistance of resulting polyimide but would not significantly reduce the glass transition temperature. The results suggested that the obtained polyimide has excellent thermal properties, which were similar to the thermosetting polyimides 19 and the quaternary copolymerized thermoplastic polyimide. Obviously, the resulting polyimide was stable up to 400 C and did not present conspicuous mass loss before this temperature.…”

Section: Thermal Analysismentioning

confidence: 64%

“…19,20 Thermal stability of the resulting polyimide is necessary to be studied to verify the influence of hydrothermal method on their thermal properties. 19,20 Thermal stability of the resulting polyimide is necessary to be studied to verify the influence of hydrothermal method on their thermal properties.…”

Section: Introductionmentioning

confidence: 99%

Green facile fabrication of polyimide by microwave‐assisted hydrothermal method and its decomposition dynamics

Zhuo

Tang

Zhao

et al. 2019

J of Applied Polymer Sci

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A microwave-assisted hydrothermal technique was proposed in this work to fabricate polyimide using ethanol as sole solvent, and the decomposition dynamics of the resulting polyimide was also investigated. The preparation process involved that the ammonium carboxylic ester intermediates could be able to cyclize de-alchoholation, thus generating imide ring structures. The obtained polyimide exhibited excellent thermal properties. Specifically, the glass transition temperature of the polyimide was around 267.8 C, and it begun to decompose gradually from about 550 C. A novel method was employed to choose the dynamics model according to the linear correlation between g(α) and 1/β. As a result, the three-dimensional diffusion (Jander) model was much more suitable for the thermal decomposition process of the resulting polyimide, and the thermal decomposition mechanism was explained by using the model. The apparent activation energy (E a ) values calculated by Flynn-Wall-Ozawa and Kissinger methods were similar showing the same variation tendency. Furthermore, a series of fitting polynomials for E a and pre-exponential factor (A) values were achieved to reflect the trend more accurately. The dynamics results revealed that the decomposition process was complex and could be regarded as multistep reactions.

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“…This may be because the post-curing process of the resin increases the cross-linking density, decreases the free volume of the polymer, decreases the activity of the molecular chains, and decreases the average chain length between adjacent cross-linking points; the physical aging and post-curing reactions may cause the material T g to rise. 38,39 However, long-term thermal–oxidative aging may cause degradation of the resin and destruction of the molecular structure, resulting in a decrease in the T g . 40 The T g of the material after aging for 1920 h still exceeds that of the unaged composite, indicating that the resin has good heat-resistant oxidative aging properties.…”

Section: Resultsmentioning

confidence: 99%

Effects of thermal–oxidative aging on the mechanical properties of open-hole T800 carbon fiber/high-temperature epoxy composites

Jia

et al. 2019

High Performance Polymers

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T800 carbon fiber/high-temperature epoxy resin composites with holes were subjected to thermal–oxidative aging, and the effects of different aging temperatures and times on the composite properties were investigated. The mass loss, surface topography, open-hole tensile performance, fracture morphologies, dynamic mechanical properties, and infrared spectra were analyzed. The results showed that chemical aging did not occur with thermal–oxidative aging at 70°C and 130°C. However, chemical aging occurred at 190°C. At 70°C, 130°C, and 190°C, all samples showed a slight increase followed by a slight decrease and stabilization in the open-hole tensile strength. The open-hole tensile strength was maximized after 240 h aging at different temperatures; the open-hole tensile strength after 1920 h aging exceeded that of the unaged samples. All composites experienced through-hole failure. With aging, the glass transition temperature ( T g) was gradually increased and then decreased. After 960 h aging at different temperatures, T g was maximized.

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High thermally stable thermosetting polyimides derived from a carborane-containing tetramine

Cited by 11 publications

References 30 publications

Effects of aging process and testing temperature on the open-hole compressive properties of a carbon fiber composite

Effects of aging process and testing temperature on the open-hole compressive properties of a carbon fiber composite

Green facile fabrication of polyimide by microwave‐assisted hydrothermal method and its decomposition dynamics

Effects of thermal–oxidative aging on the mechanical properties of open-hole T800 carbon fiber/high-temperature epoxy composites

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