Properties of Alicyclic Polyimides with Bis-spironorbornane Structure Prepared in Various Solvents

Abstract

An alicyclic tetracrboxylic dianhydride having cyclopentanone bis-spironorbornane structure (CpODA) was polycondensated with aromatic diamines in the various kinds of solvents. The poly(amic acid)s were imidized by a chemical and a thermal methods. In chemical imidization of poly(amic acid) derived from CpODA and 2,2'-dimethyl-1,1'-biphenyl-4,4'-diamine in N,N-dimethylacetamide and -butyrolactone the polyimides precipitated as the reaction proceeded. The precipitates, however, were soluble in hologenated solvents such as CHCl3. The solution processable polyimides formed colorless and flexible films after cast then dried. All the polyimide films possessed excellent thermal stability and had glass transition temperatures over 322 o C. The coefficient of thermal expansion (CTE) values of chemically imidized polyimide films were lower than those of thermally imidized ones and there was only a small difference in CTE among polyimide films prepared in different polymerization solvents. The polyimide films exhibited cut-off shorter than 298 nm, and the values of transparency in the visible region were over 84% and highly colorless.

Recent Trends on Transparent Colorless Polyimides with Balanced Thermal and Optical Properties: Design and Synthesis

“…A cycloaliphatic tetracarboxylic dianhydride with a cyclopentanone bis‐spironorbornane structure (CPODA, Figure ) has been reported by Matsumoto et al . PIs obtained via chemical imidization were highly soluble, which can be attributed to the bulky and twisted steric structure of CPODA.…”

“…A cycloaliphatic tetracarboxylic dianhydride with a cyclopentanone bis-spironorbornane structure (CPODA, Figure 4) has been reported by Matsumoto et al [188] PIs obtained via chemical imidization were highly soluble, which can be attributed to the bulky and twisted steric structure of CPODA. For the CPODA/m-toluidine system, solution casting after chemical imidization results in a colorless PI film with a somewhat low CTE (38 ppmK -1 ) and a high T g (323 °C).…”

Preparation and Characterization of Semi-Alicyclic Polyimides Containing Trifluoromethyl Groups for Optoelectronic Application

“…Those PIs with non-aromatic units exhibit high transparency and meantime low coloration compared to fully-aromatic PIs. Especially, semi-alicyclic PIs derived from alicyclic dianhydrides and aromatic diamines are taken as the best choice to obtain transparent PIs with high transmittance because their reactions can proceed smoothly without salt formation [ 22 , 23 , 24 , 25 ]. In the previous work [ 26 ], semi-alicyclic PIs based on 1,2,4,5-cyclohexanetetracarboxylic dianhydride (H-PMDA, also named CHDA) and various aromatic diamines were prepared and showed considerably improved optical transparency with entirely colorless appearance.…”

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

“…In order to overcome the drawback of deep coloration of PIs, which is caused by intra‐ and intermolecular charge transfer interactions, many structural modification strategies have been utilized . The most effective approach is to use aliphatic tetracarboxylic dianhydrides or aliphatic diamines, which would enlarge the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, and shift the absorption wavelength from the visible region to the ultraviolet (UV) region . For the former, there are many reports focusing on semi‐aromatic PIs derived from alicyclic dianhydrides with different ring sizes .…”