Preparation and characterization of new polyimides derived from 2,2-bis[4-[2-(4-aminophenoxy)ethoxy]phenyl]sulfone

Abstract

A new diamine containing sulfone and oxyethylene unit, 2,2‐bis[4‐[2‐(4‐aminophenoxy)ethoxy]phenyl]sulfone (BAEPS), was used as a monomer with various aromatic tetracarboxylic dianhydrides to synthesize polyimides via a conventional two‐step procedure. The diamine was prepared through the aromatic nucleophilic substitution of bis[4‐(2‐hydroxyethoxy)phenyl]sulfone with p‐fluoronitrobenzene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine monohydrate/Pd–C. Depending on the dianhydrides used, the poly(amic acid)s obtained had inherent viscosities of 0.90–1.32 dl/g. All the poly(amic acid)s were cast from the N,N‐dimethylacetamide solution and thermally converted into transparent, flexible and tough polyimide films. The polyimide films had a tensile strength range of 74–151 MPa and tensile modulus between 1.9 and 3.0 GPa. Almost all the polymers were amorphous except for that derived from dianhydride pyromellitic dianhydride (PMDA). The polyimide derived from 4,4′‐hexafluoro‐isopropylidenediphathalic anhydride exhibited excellent solubility in various organic solvents. These polyimides had moderate glass transition temperatures of between 185 and 222°C. The PMDA‐based polyimide exhibited melting temperature at 413°C. The 10% mass loss temperatures of the polyimides were recorded in the range of 445–468 and 433–452°C in nitrogen and air atmosphere, respectively. Copyright © 1999 John Wiley & Sons, Ltd.

Synthesis and properties of high performance polyimides derived from a novel diamine containing a N-octylcarbazole unit and two 3,5-diarylimidazole groups

“…6,7 Because of the interest that they have generated, considerable efforts have been made to modify their chemical structure to achieve a particular property for a specific application. The incorporation of flexible linkage in the main chain [8][9][10][11][12] or flexible alkyl side chains, 13 utilization of noncoplanar 14,15 or alicyclic monomers 16,17 and incorporation of bulky pendants in the polymer backbone [18][19][20][21][22][23] have been utilized which result in good solubility and processibility of the polyimides either by lowering the inter-chain interactions or by reducing the stiffness of the polymer backbone. The rigidity, symmetry and polarizability of heteroaromatic rings such as imidazole and its derivatives can contribute to thermal and chemical stability, and enhance the mechanical properties of the resulting polymer, and can also improve the photophysical properties of polymer greatly due to their electron accepting affinity; 23,24 in addition, increased polarizability resulting from the nitrogen atom in imidazole ring improves the solubility of the polymer in organic solvents.…”