Poly(ether amide) segmented block copolymers with adipicacid based tetra amide segments

Poly(tetramethylene oxide)-based poly(ether ester amide)s with monodisperse tetraamide segments were synthesized. The tetraamide segment was based on adipic acid, terephthalic acid, and hexamethylenediamine. The synthesis method of the copolymers and the influence of the tetraamide concentration, which was varied between 3 and 44 wt %, were studied. The copolymers were characterized by differential scanning calorimetry and temperature-dependent Fourier transform infrared, small-angle X-ray scattering, atomic force microscopy, and dynamic mechanical thermal analysis. The monodisperse tetraamide segments crystallized fast, forming crystalline ribbons with high aspect ratios, and the crystallinity of the tetraamide segments in the copolymers was typically 90%. The glass-transition temperature of the poly(tetramethylene oxide) phase was low (-65 to -70°C), and the modulus in the plateau region of the copolymers was virtually temperature-independent. With increasing content of crystallizable amide segments in the copolymer, the storage modulus at room temperature increased from 1 to 102 MPa. This strong increase in the modulus with the tetraamide content could be approximated with a model for fiber-reinforced polymers