Soluble polyimides with polyalicyclic structure. 1. Polyimides from bicyclo[2.2.2]oct-7-ene-2-exo,3-exo,5-exo,6-exo-tetracarboxylic 2,3:5,6-dianhydrides

Abstract

3:5, and its 1-methyl analogue (3b) were synthesized by a one-pot Diels-Alder (DA) reaction from maleic anhydride, and 4,5-dibromocyclohexane-l,2-dicarboxylic anhydride (2a) and 3-methyl-4,5-dibromocyclohexane-1,2dicarboxylic anhydride (2b), respectively. Each tetracarboxylic dianhydride was also prepared directly without isolation of the bromine adduct (2a or 2b) from the reaction product of bromine with 4-cyclohexene-l,2dicarboxylic anhydride (la) or 3-methyl-4-cyclohexene-1,2-dicarboxylic anhydride (lb). The polyimides prepared from 3a and 3b with aromatic diamines were soluble in aprotic and protic polar solvents and possessed molecular weights in the range from 1.6 x 104 to 4.6 X 104. The polyimide films were revealed to be almost colorless. Thermal gravimetric analysis gave an indication that these polyimides had good thermal stability with no significant weight loss up to approximately 360 °C. A thermal decomposition mechanism is proposed on the basis of GC-MS analysis on the pyrolyzed products of the model compounds 6a and 6b, and it is concluded that the decomposition in nitrogen was a consequence of the retro-DA reaction of polymer chains.

Optical Properties of Polyalicyclic Polyimides.

“…[1][2][3][4][5] We have already achieved the synthesis of nearly colorless polyimides using dianhydrides with polyalicyclic structures. [6][7][8] Moreover, we reported entirely colorless polyimides prepared from a dianhydride with a bicyclo[2.2.1]heptane structure and aromatic diamines, although it was essential that a mixture of triphenylphosphite and pyridine (TPP/Py) was added during the course of the polymerization process. [9] The obtained polyimide film showed a cutoff at around 280 nm and was entirely transparent and colorless.…”

Synthesis and Properties of Novel Fluorinated Polyamides Based on Noncoplanar Sulfoxide Containing Aromatic Bis(ether amine)

“…To develop easily processable high performance polymers, modifications that increase the solubility while maintaining the thermal stability are of particular interest. One of the successful approaches to increase solubility and processability of polyamides is by the introduction of flexible bonds, [5][6][7][8][9] unsymmetric and less symmetric such as meta-or ortho-linkages, [10][11][12] alicyclic, 13,14 and kinked structures. 15 Another approach employed to increase the solubility of rigid-rod polyamide is by incorporation of the nonlinear moieties such as a bulky noncoplanar groups in the polymer backbone.…”

Soluble Copolyimides Based on 2,3,5-Tricarboxycyclopentyl Acetic Dianhydride and Conventional Aromatic Tetracarboxylic Dianhydrides

“…1 Aromatic polyimides such as pyromellitic polyimides are prepared from aromatic diamines and aromatic tetracarboxylic dianhydrides via poly(amic acid)s. Since conventional aromatic polyimides are insoluble, these polymers are usually processed as the corresponding soluble poly(amic acid) precursors, and then either thermally or chemically imidized. However, there are some problems owing to the unstability of poly(amic acid)s and the liberation of water in imidization process.…”