Synergistic Effect of Graphene Oxide and OH-MWCNTs on the Cure Kinetics of an Epoxy-Anhydride System

Zhang, Jing; Chen, Kaijun; Lv, Shunzeng; Zhou, Yifan; Ma, Xu; Tang, Jijun

doi:10.2320/matertrans.m2018377

Cited by 3 publications

(1 citation statement)

References 18 publications

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“…For the n th -order reaction, the value of lnA can be obtained from the known values of ln (da/dt) and E a /RT from Equation (6). [19][20][21] [ ] Figure 4 exhibits the Friedman plots of the isothermal imidation process in the a range between 0.1 and 0.5 by Equation (5). The difference of a value is 0.05.…”

Section: Model-free Studymentioning

confidence: 99%

Isothermal imidation kinetics of polymethacrylimide based on in-situ FTIR

Zhang¹,

Ma²,

Huang³

et al. 2019

Mater. Tehnol.

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The isothermal imidation process of polymethacrylimide (PMI) prepared from acrylonitrile (AN), methacrylic acid (MAA) and alpha-methylstyrene (AMS) was investigated by "in-situ" Fourier transform infrared spectroscopy (FTIR) at different temperatures, ranged between 180°C and 200°C. The bending vibration absorption peak of hydrogen on the benzene ring in AMS at 700 cm-1 was selected as the internal standard. The extent of the imidation was defined by the area ratio of the characteristic absorption peak of the nitrile groups at 2243 cm-1 to the internal standard. The plots of imidation extent versus time were analyzed by the Friedman method and the Avrami equation. The activation energy at the imidation extent between 0 and 0.2 was 60.4 kJ/mol to 65.1 kJ/mol, which was ascribed to the reaction of the forming imide ring structures. The increase of the activation energy from 65.1 kJ/mol to 92.3 kJ/mol at the imidation extent between 0.2 and 0.4 can be ascribed to the reaction of forming polyimine cyclic structures. At the imidation extent higher than 0.4, the activation energy decreased from 92.3 kJ/mol to 52.1 kJ/mol and the frequency factor (lnA) fell from 20.5 s-1 to 12.6 s-1. At this stage, the reaction was controlled by diffusion. Moreover, the Avrami curves were in good agreement with the experimental data of the imidation, except for the late stage. The decrease of the kinetic constant from 2.14×10 4 s-1 to 0.92 s-1 and activation energy from 54.05 kJ/mol to 20.39 kJ/mol further indicated that the imidation mechanism of the AN/MAA/AMS co-polymer system changed from kinetically controlled at the prophase to diffusion controlled at the anaphase.

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