COOPERATIVE STRUCTURE FORMATION BY DIRECTED NONCOVALENT INTERACTIONS IN AN UNIPOLAR POLYMER MATRIX .7. DIFFERENTIAL SCANNING CALORIMETRY AND SMALL-ANGLE X-RAY-SCATTERING

4-Urazoylbenzoic acid groups which are attached randomly to flexible 1,4-polybutadienes form ordered supramolecular domains via hydrogen bonds and dipole-dipole interactions. The influence of the backbone molecular weight on the degree of supramolecular ordering is studied by differential calorimetry (DSC) and small-angle X-ray scattering (SAXS). The ordered domains formed by the functional groups are phase separated from the amorphous polymer matrix, giving rise to a maximum in the small-angle X-ray scattering. From the enthalpy change associated with the order-disorder transition and the SAXS data the dimensions of the ordered supramolecular domains are estimated. The number of polar groups incorporated into a single ordered domain is in the range of 20-90. Between 5 and 20 units form a single association chain.