LC-polyimides: 5. Poly(ester-imide)s derived from N-(4-carboxyphenyl) trimellitimide and α,ω-dihydroxyalkanes

Abstract

N-(4-carboxyphenyl)trimellitimide was prepared from trimellitic anhydride and 4-aminobenzoic acid and esterified with methanol. Transesterification with α,ω-dihydroxyalkanes in the melt yielded a series of poly(ester-imide)s with varying spacer lengths. These poly(ester-imide)s were characterized by elemental analyses, inherent viscosities, differential scanning calorimetry measurements, wide angle X-ray spectroscopy powder and fibre patterns, including synchrotron radiation measurements at variable temperature, optical microscopy with polarized light, and thermogravimetric analyses. Poly(ester-imide)s with even-numbered spacers can form three different kinds of solid phase, including a smectic glass and a crystalline smectic phase. Fibre patterns of melt-spun fibres indicate a high degree of order for series of subsequent layers, even when any order inside the layers is lacking. Poly(ester-imide)s with odd-numbered spacers crystallize much more slowly and can be quenched from the isotropic melt, so that isotropic glasses can be obtained.