Synthesis and properties of novel soluble polyimides having an unsymmetric spiro tricyclic dianhydride unit

Abstract

A novel spiro trialicyclic dianhydride, rel[1S,5R,6R]‐3‐oxabicyclo[3.2.1]octane‐2,4‐dione‐6‐spiro‐3′‐(tetrahydrofuran‐2′,5′‐dione) (DAn) was synthesized from itaconic anhydride (1) and cyclopentadiene via a Diels‐Alder reaction, nitric acid oxidation, and the subsequent dehydration with acetic anhydride. The structure of DAn was determined by NMR spectra and single crystal X‐ray diffraction. A series of soluble polyimides (PIs) having a spiro alicyclic unit in the main chain were prepared by the reactions of DAn with several diamines through a general two‐step polymerization method. Polymerization temperature affected inherent viscosities of poly(amic acid)s. Chemically imidized PIs had the inherent viscosities in the range of 0.10–0.49 dL/g. Due to the unsymmetric spiro alicyclic structure, the PIs showed excellent solubility in many organic solvents. Glass transition temperatures of PIs ranged from 215 to 279°C and some of them showed no glass transition temperature. The 10% weight loss temperatures under nitrogen were in a range of 355–430°C. Films of PIs obtained by the thermal imidization were wholly transparent and colorless.

Soluble polyimides based on a novel pyridine-containing diamine m,p-PAPP and various aromatic dianhydrides

“…However, despite the excellent combined properties, their widespread applications are often limited by their poor solubility and high processing temperature, which make it impossible for most PIs to be directly processed in their imidized forms. In order to overcome these drawbacks, many efforts on chemical modifications of PIs have been made, such as introduction of flexible linkages [4][5][6], bulky units [7,8], bulky pendent substituents [9][10][11], and noncoplanar moieties [12], in the polymer backbone. Solubility of PIs can also be improved by incorporation of less symmetric structures such as ortho-or metalinked aromatic units in the main chain [13,14].…”

Advances in synthetic optically active condensation polymers - A review

“…The resulting polymers showed good solubility toward dipolar aprotic solvents and Py [120]. Kudo's group also successfully synthesized a series of optically active and soluble PIs having a spiro alicyclic unit in the main chain by the reactions of DAn with several diamines through a general two-step polymerization method [121][122]. In another research, they reported on a systematic investigation of the physical properties of coPIs of DAn [123].…”

“…Synthesis of optically active coPIs derived from DAn [119][120][121][122][123] DMF system as condensing agent. The resulting polymers were obtained in good yields with inherent viscosities ranging between 0.21 and 0.61 dL/g.…”

Design and preparation of novel fluorescent polyimides containing ortho-linked units and pyridine moieties

“…To overcome poor solubility, many efforts on chemical modifications of PIs have been made, such as introduction of flexible linkages [24,25], bulky units or bulky pendent substituents [26][27][28][29], and noncoplanar moieties [30], in the polymer backbone. However, such groups often reduce glass transition temperature, compromising ultimate performance.…”