Synthesis and characterization of soluble polyimides derived from a novel unsymmetrical diamine monomer: 1,4-(2′,4″-diaminodiphenoxy)benzene

Synthesis and characterization of trifluoromethylated poly(ether–imidazole–imide)s based on unsymmetrical diamine bearing carbazole and imidazole chromophores in ionic liquids: Study of electrochemical properties by using nanocomposite electrode

“…Solubility of the PIs has been targeted by several methods, such as introduction of flexible linkage, bulky units in the polymer backbone, bulky pendent substituents, or noncoplanar moieties. Among these approaches, introduction of bulky pendants and heteroaromatic rings into the polymer chains has provided not only enhanced solubility but also good thermal stability and processability [14][15][16][17][18][19][20][21]. There are reports of using imidazole and carbazole rings and their derivatives into polymeric frameworks to improve the solubility of the polymers, which have also been suggested as promising photoconductive and photorefractive materials [22][23][24].…”

Solubility and liquid crystal vertical alignment of polyimides derived from a new diamine: 4-((4-dodecyloxy)phenyl)-2,6-di((4-amino)phenyl)pyridine

“…[1,2] However, on account of their rigid backbones and strong interaction between chains, most of them have high glass transition temperatures (T g s) or melting temperatures and limited solubility in organic solvents, [3,4] which may restrict their applications. Traditionally, most PIs are prepared by a two-step method in which polyamic acid (PAA) was formed from the polycondensation of the monomers and subsequently transformed into PIs by thermal or chemical imidisation.…”

“…[5,6] However, the pot-life of PAA solutions is short because PAA may undergo partial imidisation or decomposition at room temperature. [7][8][9] In order to improve the solubility of PIs, considerable efforts have been made to modify the chemical structure by introducing bulky groups, [10][11][12] flexible linkages, [1,13,14] fluorine-containing groups, [15] asymmetric units [2,16] and alicyclic groups [17] into the backbones or by copolymerisation. In our previous work, Sun et al [18,19] synthesised diamines containing alkyl-chains or tert-butyl.…”

Synthesis and characterization of branched phenylethynyl-terminated polyimides

“…The main methods include insertion of flexible linkage on the main chain [12,13], utilization of noncoplanar or asymmetric monomers [5,[14][15][16], the incorporation of bulky pendant groups into the polymer backbones [17,18], etc. However, the monomers mentioned above are often scarce, expensive, and difficult to achieve industrial production.…”