Superheat-resistant polyimides with ultra-low coefficients of thermal expansion

Polyimides with low coefficient of thermal expansion derived from diamines containing benzimidazole and amide: Synthesis, properties, and the N‐substitution effect

“…The PBIAI films exhibited a broad diffraction peak centered at 2θ = 21°, typical of an amorphous material, which was consistent with the findings of other reported PIs containing amide groups 19,31,32 . Generally, the PBII films showed definitive crystalline structures resulted from their rigid polymer backbone 12,13,15 . In this research, the introduced amide segments tended to form intermolecular hydrogen bonds (CO…NH) and the interactions destroyed the regular arrangement, resulting in the destruction of the crystal structure derived from the benzimidazole units.…”

“…It could be inferred that these synthesized diamines would possess higher nucleophilicity than full-phenyl diamines because of the strong electron-donating property of benzimidazole groups, which might provide PIs with enhanced thermal properties with the improved CT interactions. 15,21,22 Furthermore, to assign the aromatic protons of N-Ph in the 6c, 1 H-1 H COSY spectra (Figure 2) had been given and the data accorded with the expected structure.…”

“…Their high T g (above 400°C) can be ascribed to the intermolecular hydrogen bonds and strengthened charge‐transfer (CT) interactions. However, their CTE values (slightly greater than 10 ppm K −1 ) cannot be perfect content with the high dimensional stability requirements of substrates 14,15 . In previously reported articles, the incorporation of amide groups (NHCO) in PIs cause a dramatic reduction in the CTE 16,17 .…”

“…However, their CTE values (slightly greater than 10 ppm K −1 ) cannot be perfect content with the high dimensional stability requirements of substrates. 14,15 In previously reported articles, the incorporation of amide groups ( NHCO ) in PIs cause a dramatic reduction in the CTE. 16,17 The initial reason is the high linearity of these connecting units does not disturb the extended chains formation.…”

Incorporation ofN-phenyl in poly(benzimidazole imide)s and improvement in H2O-absorbtion and transparency

“…12,13 Among them, the traditional PBIIs can be used as a candidate material for exible substrates in various image display devices; however, their high W A may lead the package cracking, degradation of dielectric properties, and failures of the adhesion to metal, restricting the application. 13,14 Hence, low H 2 O-absorption PBIIs without compromising their superior properties are desirable.…”