Synthesis and properties of 6FDA‐BisAAF‐PPD copolyimides for microelectronic applications

Abstract

ABSTRACT:In this work, fluorine-containing copolyimides were synthesized from 6FDA dianhydride and different ratios of BisAAF and PPD diamines. Properties, such as composition, viscosity, dielectric constant, glass-transition temperature, thermal decomposition temperature, tensile characteristics, and transmittance, were investigated by using elemental analysis, viscometry, Fourier transform infrared spectrometry, differential scanning calorimetry, a thermogravimetric analyzer, a tensile tester, and UV-visible spectrophotometry. After curing at 300°C for 1 h, imidization was observed, as indicated the appearance of an absorption peak of the carbonyl of the imide at 1780 cm Ϫ1 (CAO asymmetry stretching). The inherent viscosity increased with an increasing PPD mole fraction, from 0.40 dL/g of pure 6FDA-BisAAF to 0.84 dL/g of pure 6FDA-PPD. The dielectric constant decreased with increasing fluorine content. The glass-transition temperature increased with an increasing PPD mole fraction; the values increased from 317°C with pure 6FDA-BisAAF polyimide to 364°C with pure 6FDA-PPD polyimide. The 5% weight loss temperature (T d ) of the copolyimides was around 530°C in air and 540°C in a nitrogen atmosphere. The tensile modulus and tensile strength gradually increased with an increasing PPD molar fraction. The transmittance of 6FDA-BisAAF-PPD copolyimides was greater than 90% at wavelengths above 500 nm.

Atomistic models of three fluorinated polyimides in the amorphous state

“…The industrial applications of 6FDA‐based polyimides are numerous and range from electronics,8 electrical9 and optical engineering,10, 11 radiation resistance,12 and aviation13 to filtration membranes 3, 4. For example, these polyimides are used in microelectronics to prepare the intermetal dielectric and passivation layers 9. When they are used as an insulating material, the speed of the signal transmission in the electrical circuit increases 6.…”

Colorless polyimide nanocomposite films containing hexafluoroisopropylidene group

“…The most lightly colored pure PIs can be explained by their shorter λ o values, because the presence of the CF 3 groups in the monomers significantly reduces the formation of the charge‐transfer complex as well as the intermolecular interactions. The superior transparency of these 6FDA‐based PIs may be due to the limited electronic conjugation along their backbones 42, 43. However, the values of λ o were found to increase with linear increases in the organoclay content, which is due to agglomeration of the clay particles.…”

Flexible thermochromic foil derived from fine perovskite nanoparticles with excellent energy‐saving performance

“…Unfortunately, the yellow color in the conventional PIs tends to trap more solar radiation, causing a boosted temperature. In addition, it is also unsuitable for application in where the transparency is required . In order to avoid the side effect of deep‐color PIs, the fluorated‐PIs (FPIs) with outstanding thermal stability, transparency, and low solar absorption is presented.…”

“…Aromatic polyimides (PIs) are regarded as excellent host polymer owing to their high temperature resistance, space environment endurance, and good optical property. [9][10][11][12][13] Unfortunately, the yellow color in the conventional PIs tends to trap more solar radiation, causing a boosted temperature. In addition, it is also unsuitable for application in where the transparency is required.…”

“…In addition, it is also unsuitable for application in where the transparency is required. [9][10][11] In order to avoid the side effect of deep-color PIs, the fluorated-PIs (FPIs) with outstanding thermal stability, transparency, and low solar absorption is presented. In our previous work, 14 FPIs containing CF 3 group meeting the mentioned-above features have been reported, which motivates the present study.…”