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

Abstract

A novel heterocyclic diamine based on carbazole and imidazole rings, 5,5 0 -(9-octyl-carbazole-3,6-diyl)bis[4-phenyl-2-(4-amino-phenyl)-1H-imidazole], was synthesized from readily available compounds through a multi-step procedure in high yield. The obtained diamine was fully characterized and its polycondensation reaction with different aromatic dianhydrides via the conventional two-step method, ring-opening polycondensation and chemical imidization, led to preparation of novel photoactive and heat resistant polyimides with improved solubility. The effects of the heteroaromatic rings into the main chain of the prepared polyimides were evaluated through the study of their solubility, thermal and optical properties. The inherent viscosities of the resulting polyimides were in the range of 0.39-0.51 dL g À1 , and all of them were soluble in common polar aprotic solvents. Meanwhile, they had good thermal stability with glass transition temperature (T g ) values of 312-330 C, the temperature at 10% weight loss of 475-495 C, and the residue at 700 C of 61-65% in nitrogen. These polymers exhibited strong UV-vis absorption, and their photoluminescence (PL) spectra showed maxima at 413-426 nm in solution and at 429-438 nm in the solid state. Wide-angle X-ray diffraction measurements revealed that these polyimides were predominantly amorphous.

Influence of graphene oxide on thermal, electrical, and morphological properties of new achiral polyimide

“…These polymers have high glass transition temperatures ( T g s) or high melting temperatures ( T m ) and limited solubility in organic solvents which restricts the extended commercial application. Research has been carried out worldwide to overcome these issues by incorporating flexible linkages, asymmetric centres and aliphatic groups . Among these methods introducing aliphatic chain containing monomers in the polymer chains is an effective way to convert polymeric materials to stable forms for improving their solubility which overcomes the processing difficulty.…”

Study properties of nanocomposites prepared with new polyimides and reactive nanosilica by epoxide functionalization

“…In the present work, a new diamine (DAQC) was synthesized through multi‐steps synthetic route. The synthetic procedure was almost similar to our previous reported method . A series of PCQIs containing quinoxaline and carbazole rings in their main chain were synthesized in good yields (90–95%) by using the conventional two‐stage procedure.…”

“…The excellent solubility of PCQI(c) can be due to dianhydride 6FDA in the backbone with C(CF 3 ) 2 groups, which prohibits a close packing of the chains and increases the interaction with polar molecules of solvent. Comparison of solubility of the previously reported polyimides with PCQIs indicates that presence of long alkyl side chain and phenyl side group in the backbones of PCQIs have improved solubility despite the presence of rigid units such as quinoxaline and carbazole rings in the main chains. Nanocomposites containing 5 and 10 wt% mSiO 2 did not dissolve in the above mentioned solvents even on heating.…”

Synthesis and properties of electroactive aromatic polyimides with methyl- or trifluoromethyl-protecting triphenylamine units

“…Tremendous efforts have also been made on the modification of the backbone structure of polyimides to obtain organosoluble or melt processable polyimides without much sacrificing their excellent thermal and mechanical properties. [24][25][26][27][28][29][30][31][32][33] Triphenylamine (TPA) and its derivatives with special propeller-shaped molecular structure are well-known for their ease in oxidation of the nitrogen core and the ability to transport charge carriers via the radical cation species with high stability. [34][35][36] Owing to their attractive electroactive and photoactive properties, various TPA derivatives and polymers are developed for optoelectronic applications, such as electrophotography, electroluminescent diodes, field-effect transistors, solar cells, memory devices and electrochromic devices.…”