Synthesis of new alicyclic polyimides by Diels‐Alder polymerization

Abstract

Four new alicyclic poly{arylene-9,10-di[4-(methyloxy)phenyloxy]-1, 2,3,4,5,6,7,3,6, were prepared at 808C in the presence of NaI in DMSO by the in situ Diels-Alder polymerization of 1,4-bis[4-(methyloxy)phenyloxy]-2,3,6,7-tetrakis(bromomethyl)benzene (MPBB) with four arylenebismaleimides (AMIs). The stereochemical isomerisms measured for the model compound DPAI and MDA-PI by HETCOR spectroscopy and 1 H-NMR spectroscopy, respectively, revealed that DPAI and APIs presumably have only one trans-bis-endo-configuration. Inherent viscosities of APIs varied in the 0.20-0.41 dL/g range. Solubility tests revealed that in spite of the alicyclic units incorporated the APIs were only marginally soluble in polar organic solvents. In TGA in N 2 the APIs began to decompose at temperatures higher than 3808C, revealing two-step pyrolysis behavior. 4-(Methyloxy)-phenyloxy side groups were believed to degrade in the lower temperature range. In DSC and wide-angle X-ray diffractometry APIs all appeared completely amorphous and in UV-Vis spectroscopy both DPAI and APIs were transparent at wavelengths longer than 375 nm.

Colorless Polyimides Derived from Octahydro-2,3,6,7-anthracenetetracarboxylic Dianhydride

“…This new monomer is expected to significantly improve the polymerizability owing to its spacer effect while further enhancing the T g of the resultant PI films owing to its rigid ladder-like structure. The present study was inspired by previous work, in which the synthesis of 9,10-diphenoxy-or 9,10-dialkoxy-substituted OHADA analogs and some limited properties of the resultant PIs (solubility and thermal stability) were reported [53][54][55]. However, it remained unclear whether these materials are valuable for optoelectronic applications since other important properties (optical transparency, glass transition temperatures, thermal expansion property, mechanical properties, and thermoplasticity) were not provided in the previous studies.…”