| 摘要 |
PURPOSE:To obtain a polyimide outstanding in processability, low water absorptivity, solvent and alkali resistances etc., suitable for aerospace base materials, having specific recurring unit, by imide modification of specific polyamic acid. CONSTITUTION:The objective polyimide having recurring unit of formula II can be obtained by imide modification of a polyamic acid with a logarithmic viscosity 0.1-4.0 (pref. 0.3-2.5dl/g) determined in the form of N,N- dimethylacetamide solution of a concentration 0.5g/100ml at 35 deg.C, having recurring unit of formula I prepared by reaction pref. between 4,4-bis(3-aminophenoxy) biphenyl and pyromellitic anhydride in an organic solvent.
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