STRUCTURE AND THERMOMECHANICAL PROPERTIES OF HIGH-MODULUS ARAMIDE COPOLYMERS: (II) THERMOMECHANICAL ANALYSIS AND MEASUREMENT OF THE ULTRASONIC AND CRYSTALLITE MODULI AS A FUNCTION OF TEMPERATURE

The crystallite modulus El has been measured by the X-ray diffraction method for aramide copolymer (M50), synthesized by the condensation polymerization between p-phenylenediamine/3, 4'-diaminodiphenylether equimolar mixture and terephthalic chloride, and the homopolymers of each component 1 and 2; The values are compared with the macroscopic moduli Es measured by the ultrasonic method; An introduction of other kind of monomer unit was found to decrease the crystallite modulus of PPTA remarkably. The thermal shrinkage and the temperature dependence of sonic compliance have been measured for the M50 fiber based on the thermomechanical analysis; the curves are found to show the several deflection points at the temperatures corresponding to the structure changes reported in the previous paper (Sen-i Gakkaishi, 43, 627 (1987)).