The relaxation mechanical properties of aromatic polyimides of varying structure

Bessonov, M.I.; Кузнецов, Н. П.; Adrova, N.A.; Florinskii, F.S.

doi:10.1016/0032-3950(74)90247-0

Cited by 19 publications

(3 citation statements)

References 5 publications

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“…Using the C 1 and C 2 obtained from Figure 7 and equation (5), the activation energy for alpha relaxation was determined to be 672.8 kJ/mole, which has the same value as the one calculated based on the GRG analysis method. The relatively high value of the activation energy obtained is not surprising and is in the same range as those reported by Bessonov et al 25 who studied different aromatic polyimides. The activation energy obtained for polyimide nanocomposites is high compared to those reported for linear polymers and their composites due to the rigid and aromatic chemical structures of polyimide and the high cohesive energy density that increases the thermal stability of polyimide composite.…”

Section: Resultssupporting

confidence: 87%

Viscoelastic behavior and construction of master curve for graphene/polyimide nanocomposites

Marashdeh

Iroh

2016

High Performance Polymers

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Dynamic mechanical spectroscopy is used to investigate the variation of the glass rubbery transition temperature ( Tg) of graphene/polyimide nanocomposites. The Tg was obtained as the temperature corresponding to the peak of the tan δ versus temperature curve for the alpha transition. Cole–Cole curve was constructed for the matrix and the composites composite at 1 Hz and a hemispherical curve was obtained suggesting that the constituents have similar relaxation behavior. The time–temperature superposition principle was used to model the behavior of the nanocomposites at lower frequencies and longer times. Frequency sweep was performed in the range of 0.05–100 Hz at different temperatures. The storage modulus curves obtained at different temperatures (isothermal), as a function of frequency, were shifted horizontally to construct a continuous master curve. Both the generalized reduced gradient method and the Williams–Landel–Ferry (WLF) equation were used to calculate the activation energy for glass–rubber transition. The universal constants C1 and C2 were determined using the WLF equation. The dependence of relaxation time on temperature was verified.

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Section: Resultssupporting

confidence: 87%

Viscoelastic behavior and construction of master curve for graphene/polyimide nanocomposites

Marashdeh

Iroh

2016

High Performance Polymers

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“…The activation energy E a was obtained by multiplying the slope of ln f against 1/ T curve with the gas constant R and 688 and 313 kJ/mol were obtained as the activation energy for α and β transition, respectively. The activation energies obtained in this study are in the range of values reported for an amorphous polymer with aromatic backbone . Comparison of the activation energy for relaxation for polyimide and the composite shows that the energy barrier for chain relaxation is higher for the composite than polyimide, when tested under similar conditions (Figures and ).…”

Section: Resultssupporting

confidence: 59%

Relaxation behavior and activation energy of relaxation for polyimide and polyimide–graphene nanocomposite

Marashdeh

Longun

Iroh

2016

J of Applied Polymer Sci

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The relaxation behavior of polyimide and its nanocomposite containing 10 wt % of graphene was studied by using the dynamic mechanical spectrometer. Dynamic mechanical analysis of polyimide and its composite was performed as a function of temperature and frequency in the temperature range of 25-480 8C and frequency range between 0.05 and 100 Hz. The effect of increasing frequency of testing from 0.05 to 100 Hz is a significant shift from the glass transition temperature, T g , to higher temperature from 360 8C at 0.05 Hz to 420 8C at 100 Hz. The tan d peak height for both a and b transitions decreased with increasing test frequency from 0.24 at 0.05 Hz to 0.08 at 100 Hz, due to increasing restriction to chain motion. At any given testing frequency, the T g for the composite was shown to be higher than that for the matrix by about 5-10 8C. The Arrhenius equation was used to calculate the activation energy for both a and b transitions. The activation for a and b transitions for the composite and polyimide matrix were determined to be 688 and 537 kJ/mol and 313 and 309 kJ/mol, respectively, indicating that a significant increase in the energy barrier to chain relaxation occurred as a result of reinforcement of polyimide with low weight fraction of graphene. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43684.

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“…The mechanism of the 1 relaxation process of aromatic polyimides has been under active discussion. The 1 relaxation in famous PI(PMDA/ODA) was tentatively related to loss of water [9] or to interplane slippage of crystalline phases [10], but these suggestions were in conflict with other results [11,12]. Another proposed mechanism is the rotational vibrations of the phenylene and imide groups [13,14].…”

Section: Isomeric Biphenyl Polyimides: II 343mentioning

confidence: 99%

Isomeric Biphenyl Polyimides. (II) Glass Transitions and Secondary Relaxation Processes

Kochi

Chen

Yokota

et al. 2005

High Performance Polymers

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Dynamic mechanical analysis was performed on a series of the isomeric polyimides (PIs) made from the reaction of s-, a-, and i-BPDA each with 4,4′-ODA, 3,3′-ODA, 1,3,3-APB and 1,4,4-APB. The glass transitions (T g s) moved towards higher temperatures in the order of s-, a-, and i-BPDA for the para diamine-based PIs whereas the T g values showed little change for meta diamine-based PI regardless of the BPDA isomer. Conversely, the temperature of the β relaxation process increased in the order of i-, a-, and s-BPDA with any diamine. These behaviors can be interpreted in terms of the steric hindrance effects due to the configuration of BPDA isomers and diamines.

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The relaxation mechanical properties of aromatic polyimides of varying structure

Cited by 19 publications

References 5 publications

Viscoelastic behavior and construction of master curve for graphene/polyimide nanocomposites

Viscoelastic behavior and construction of master curve for graphene/polyimide nanocomposites

Relaxation behavior and activation energy of relaxation for polyimide and polyimide–graphene nanocomposite

Isomeric Biphenyl Polyimides. (II) Glass Transitions and Secondary Relaxation Processes

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