Transparent Polyimide/Organoclay Nanocomposite Films Containing Different Diamine Monomers

Abstract

Poly (amic acid) s (PAAs) were synthesized using 4,4′-(hexafluoroisopropyl-idene) diphthalic anhydride (6FDA) and two types of diamines—bis(3-aminophenyl) sulfone (BAS) and bis(3-amino-4-hydroxyphenyl) sulfone (BAS-OH). Two series of transparent polyimide (PI) hybrid films were synthesized by solution intercalation polymerization and thermal imidization using various concentrations (from 0 to 1 wt%) of organically modified clay Cloisite 30B in PAA solution. The thermo-mechanical properties, morphology, and optical transparency of the hybrid films were observed. The transmission electronic microscopy (TEM) results showed that some of the clays were agglomerated, but most of them showed dispersed nanoscale clay. The effects of -OH groups on the properties of the two PI hybrids synthesized using BAS and BAS-OH monomers were compared. The BAS PI hybrids were superior to the BAS-OH PI hybrids in terms of thermal stability and optical transparency, but the BAS-OH PI hybrids exhibited higher glass transition temperatures (Tg) and mechanical properties. Analysis of the thermal properties and tensile strength showed that the highest critical concentration of organoclay was 0.50 wt%.

Syntheses of Colorless and Transparent Polyimide Membranes for Microfiltration

“…Molecules with -OH functionalities are capable of forming intramolecular hydrogen bonds in the PI main chain and show broad stretching absorption peaks over a wide range of 3000–3300 cm −1 . Therefore, the spectrum of 6FAm-OH PI in Figure 1 shows a broad peak for the hydrogen bond between the phenolic -OH group and nitrogen in the adjacent imide rings [ 31 ]. Similar to the case of 6FAm PI, the spectrum of 6FAm-OH PI shows C=O aromatic stretching peaks at 1786 and 1718 cm −1 , and the C-N-C peak indicating imidization was observed at 1378 cm −1 .…”

Colorless and Transparent Polyimide Microporous Film with Excellent Physicochemical Property

“…Molecules with -OH functional groups are capable of intramolecular hydrogen bonding between CPI main chains and represent a broad elongation absorption peak through a wide wavenumber range (3000–3300 cm −1 ). Therefore, the APS-OH PI spectrum shows a broad peak due to hydrogen bonding between the nitrogen and the -OH group of phenol in the adjacent imide ring as shown in Figure 1 [ 22 , 23 , 24 ]. Similar to the APS CPI spectrum, the APS-OH CPI spectrum showed a C=O aromatic stretching peak a C-N-C peak indicating imidization at 1777 cm −1 , 1716 cm −1 , and 1380 cm −1 , respectively.…”

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

“…Long-established, commercial or innovative, tailor-made, functional polyimides (PIs) represent a benchmark for high-performance polymers and demonstrate many advantages, which include excellent thermo-oxidative stability, chemical inertness, high mechanical resistance, high dielectric strength, as well as a remarkable combination of thermal, mechanical, and electrical insulating properties [1][2][3][4]. Therefore, these heterocyclic polymers have found applications in many advanced technology industries, such as aviation, spaceflight, microelectronics (printed and integrated circuit board, flexible chip carriers) [5], composite materials [6], automotive, packaging industries, or separation membranes [7]. Moreover, PIs' biocompatibility was heavily explored in the last two decades and polyimide-based materials entered the high-demanding area of biomedical applications, such as cell substrates, retina stimulation implants, cortical recordings, neural stimulation devices, and others [8].…”