LC-POLYIMIDES XXXIV - NONCRYSTALLINE THERMOTROPIC COPOLY(ESTER-IMIDE)S BASED ON PET

Four series of copoly( ester-imide)s (co-PEIs) were prepared by transe sterification of poly(ethylene terephthalate), PET, with N-(4-carboxyp henyl) trimellitimide and an acetylated diphenol. Methylhydroquinone, tert. butylhydroquinone, phenylhydroquinone, and 2,7-dihydroxynaphthal ene were used as diphenols. The chemical structures of these co-PEIs w ere characterized by chemical analyses, H-1-, and C-13-NMR spectra. A low degree of crystallinity was observed when the PET content was abov e 85% mol %. Between 60 and 80 mol % PET all co-PEIs are biphasic, whe reas below 60 mol % the co-PEIs form a homogeneous nematic melt and be low the glass transition temperature (T-g) a nematic glass. The T(g)s vary continously with the molar composition but the mechanical propert ies drop sharply when the nematic phase changes to an isotropic one. ( C) 1998 John Wiley & Sons, Inc.