New polymer syntheses, 94. Thermosetting, cholesteric oligoesters containing maleimide or nadimide end groups

Twenty four cholesteric and telechelic oligoesters were prepared having two maleimide or nadimide end groups. All oligoesters were synthesized by copolycondensation of isosorbide and methyl- or tert-butylhydroquinone with suitable dicarboxylic acid chlorides in 1-chloronaphthalene at 200°C. 4-Maleimidophenol or 4-nadimidophenol was added as terminating reagent. The isolated oligoesters had inherent viscosities in the range of 0,14–0,20 dl/g (CH2Cl2/trifluoroacetic acid) and the presence of the imide end groups was confirmed by 1H and 13C NMR spectroscopy. Most oligoesters were non-crystalline materials with glass transition temperatures in the range of 105–130°C. Most oligoesters were capable of forming a Grandjean texture upon shearing of the cholesteric melt, and thermal crosslinking in the LC phase was possible upon heating to 250°C. In several cases the thermal curve allowed a fixation of the Grandjean texture.