Morphology Evolution during the Phase Separation of Polyetherimide/Epoxy Blends

Abstract

The results of time‐resolved light scattering for the phase separation of epoxy/polyetherimide/anhydride blends show that the evolution of scattering vector qm follows a Maxwell‐type relaxation equation. The relaxation time may be suggested as the time taken for the diffusion of the epoxy‐anhydride n‐mers from the PEI‐rich phase by their relaxation movement, and the apparent activation energy of the relaxation movement is obtained.Values of qm versus time at different temperatures.magnified imageValues of qm versus time at different temperatures.

Selective localization of multi‐walled carbon nanotubes in epoxy/polyetherimide system and properties of the conductive composites

“…For the selective localization of MWCNTs in PEI‐rich phase in epoxy/PEI/MWCNTs systems, it is consistent with our previous result that fillers are preferentially immersed in the slow part (higher molecular thermoplastics PEI) due to chain entanglements …”

“…In our previous work, morphology evolution and viscoelastic behavior have been studied in epoxy/PEI blends via RIPS . Because the curing temperature (150 °C) is far below the T g of PEI (≈210 °C), PEI is a slow dynamic phase (higher T g component with higher molecular weight of more than 30 000 g/mol) and the epoxy oligomer acts as a rapid dynamic phase (with lower T g ≈ −30 °C and molecular weight of hundreds in the beginning and increasing with the curing reaction).…”

Control of pore size in epoxy systems.

“…In fact, in many of the previous CIPS studies, such as those by Gan et al [31], Girard-Reydet et al [27], Inoue et al [21,22], and Remiro et al [32], SD is seen at early stages of growth, and often continues to be present, leading to co-continuous morphology even in late stages of growth. In the images obtained here, SD does not manifest at any point (as far as we could observe, there was no intermediate morphology in the transition from nano-sized pores to no pores).…”

Spontaneous Three‐Layer Formation in the Curing of Polyimide/Epoxy Blends

“…However, epoxy resins are inherently brittle, which necessitates the toughening by mixing other materials with them in various industrial uses. [1][2][3] Aromatic polyimide, which has a high glass transition temperature and high mechanical and thermal stability, has been used as a toughener, [4][5][6][7][8] and the cure kinetics, domain structures, and phase separation mechanisms have been studied for several polyimide-toughened epoxies by varying curing temperature, [9,10] initial concentration, [11,12] and molecular weight. [13] Fluorinated polyimide, which has a low dielectric constant and generally high thermal stability even under oxygen atmosphere, is expected to be a useful toughener, but an epoxy resin toughened by fluorinated polyimide has not been studied so far within our knowledge.…”