Influence of thermal treatment time on structural and physical properties of polyimide films at beginning of carbonization

Abstract

Poly(4,4'-oxydiphenylene-oxydiphthalimide) (POO) was thermally treated at 773 K for 1, 15 and 60 minutes under argon atmosphere resulting in free-standing films with intermingled characteristics between polymer and carbon-rich derivatives. Degradative thermal analysis performed by pyrolysis-gas chromatography/mass spectroscopy (Py-GC/MS) revealed CO 2 among the major products of thermal decomposition which according to electron paramagnetic resonance (EPR) passed through a radical process. X-ray diffraction (XRD) revealed thermal treated samples with semicrystalline organization that was attributed to the development of lamellae structure. Moreover, Atomic force microscopy (AFM) showed an increase in the roughness of the samples that acquired pronounced roughcast-like surface. Hence, there was an enhancement of mechanical strength and dielectric permittivity. From the data collected a mechanism of thermal decomposition was proposed.

Thermally induced chemical evolution in polyimide films investigated by X‐ray photoelectron spectroscopy

“…This suggests that the results observed can be a consequence of polymer chain alignment (thermally induced chain rearrangement), followed by the formation of intramolecular and intermolecular bonds in the polymer backbones at high temperatures. In a recent work, we demonstrated the role played by the time of thermal treatment on the PI decomposition mechanism . We found that not only the amount of products released from PI but also the type of product released is critically influenced by the treatment time.…”

Polyimide-derived graphite barrier layer adhered to seed crystals to improve the quality of grown silicon carbide

“…On the other hand, the d-spacing was 0.3419 nm for BP-P-SiCH 3 -G. The decrease in d-spacing indicated the increase in graphitization degree. 17,20,[23][24][25][26][27] The degree of graphitization was further estimated, according to the following empirical formula. 16,23,25,28 G ¼ 0:344 À d 002 0:344 À 0:3354 Â 100%…”

“…17,20,[23][24][25][26][27] The degree of graphitization was further estimated, according to the following empirical formula. 16,23,25,28 G ¼ 0:344 À d 002 0:344 À 0:3354 Â 100%…”

New High-Performance Materials: Bio-Based, Eco-Friendly Polyimides

“…These mechanisms are strongly dependent on the environment, more precisely on the presence or absence of oxygen. In the particular case of the highly stable PIs, there are also strongly time-dependent mechanisms [139][140][141].…”

“…The presence of F-or S-rich structural motifs determines other, usually toxic volatiles. The decomposition process follows several pathways: depolymerization, pyrolytic reformation, successive homolytic and hydrolytic cleavages, hydrogen ablation, progressive molecular rearrangements, and loss of organic functionality through radical scission [140,145,146]. In every pathway, CO2 remains the main degradation product, while the nature of the other volatiles is dictated by the chemical structure of the polymer.…”