Synthesis of cardo containing asymmetric poly(ether-naphthalimide-phthalimide)s

Abstract

A series of cardo based asymmetric polyimides containing bulky rigid naphthalimide and phthalimide groups were prepared from asymmetric monomer bishaloimide and bisphenols by solution polycondensation. Bishalo(naphthalimide-phthalimide) monomers containing different terminal leaving groups (Cl, F, NO 2 ) were synthesized, and the reactivity difference of these monomers was compared for the successful synthesis of polyimides. The inherent viscosities of the polyimides were in the range 0.51 − 0.60 dL g −1 in N-methyl-2-pyrrolidone at 30 ∘ C. These polyimides demonstrated good organosolubility and mechanical properties with tensile strengths of 93 − 120 MPa, tensile moduli of 3.5 − 5.3 GPa and elongations at break of 2.8% − 4.3%. The polyimides showed high glass transition temperatures (T g ) ranging from 330 to 363 ∘ C. The 10% weight loss (T 10% ) of asymmetric polyimides reached 436 − 500 ∘ C in nitrogen and 417 − 476 ∘ C in air. The water uptake of the polyimides was in the range 0.35% − 0.72%.

Recent development of polyimides: Synthesis, processing, and application in gas separation

“…The ANS monomers with bulky side group are more accessible than diamine or dianhydride counterparts. Therefore, in the last two decades, ANS polymerization has been mainly used for preparing organo-soluble lightcolored (Figure 6B) [64][65][66][67][68][69][70][71][72] and colorless PIs (Figure 6C). 65,66,68,71 Ether and isopropyl linkages as well as bulky side groups (e.g., cardo unit) are common for improving solubility in organic solvents and reduce colors.…”

“…(B) Examples of organosoluble PIs containing ether backbone linkages. Among these, most have been prepared via NAS (B1, B2, B5‐B7), and several contain varying cardo structures (B5–B7) 64,65,68,72 . (C) examples of organosoluble, colorless PIs, most of which are prepared via NAS.…”

Transparent and organosoluble cardo polyimides with different trans/cis ratios of 1,4‐diaminocyclohexane via aromatic nucleophilic substitution polymerization

“…On the other hand, the glass transition temperatures ( T g ) of resulting PIs may be decreased due to the introduction of such flexible linkages using diphenols as monomers . Fortunately, the introduction of a bulky substituent, such as a cardo group, has been demonstrated to improve the thermal properties and solubility of PIs at the same time because cardo polymers with phenolphthalein bulky side moieties could retain the rigidity of the polymer backbone and restrict the close packing of the polymer chains . More importantly, the transparency of cardo PIs can be enhanced due to the extension of the distance between the macromolecular chains, effectively suppressing conjugation and decreasing charge transfer complex formation …”

“…[31][32][33] Fortunately, the introduction of a bulky substituent, such as a cardo group, has been demonstrated to improve the thermal properties and solubility of PIs at the same time because cardo polymers with phenolphthalein bulky side moieties could retain the rigidity of the polymer backbone and restrict the close packing of the polymer chains. [34][35][36][37][38][39] More importantly, the transparency of cardo PIs can be enhanced due to the extension of the distance between the macromolecular chains, effectively suppressing conjugation and decreasing charge transfer complex formation. 29,30 In the study reported here, considering that the incorporation of cyclohexane and cardo groups would endow PIs with high transmittance and good solubility without sacrificing thermal stability, two novel series of transparent cardo PIs derived from CHDA were synthesized using cardo phthalein diphenols and bis(fluorophthalimide)s as monomers via aromatic nucleophilic substitution polymerization.…”