Synthesis and Properties of Segmented Block Poly(oxyethylene-block-esteramide)

Abstract

A series of poly(oxyethylene-block-esteramide)s (PASHs) containing p-aminobenzoic acid units were prepared by bulk polymerization of N,N’-bis(p-ethoxycarbonylphenyl) sebacamide and mixed diols of 1,6-hexanediol and poly(ethylene glycol) (PEG, MW 600, up to 34 mol%). The poly(oxyethylene-block-esteramide)s exhibited the inherent viscosity ranging from 0.61 to 0.87 dL g-1 while the parent poly(ester-amide) yielded an inherent viscosity of 0.41 dL g-1, which is attributable to chain extension and homogeneity of reaction mixture in the presence of PEG. The parent poly(ester-amide) showed relatively fast crystallization and high Tg for its alternating arrangement of ester-amide sequence, resulting in extremely brittle characteristics. However, the glass transition temperatures, Tg, of the poly(oxyethylene-block-esteramide)s containing 13–16 mol% of PEG were found in the range 31– 45 °C and demonstrated greatly improved mechanical properties. The storage modulus in ambient temperature was ca. 1300–1400 MPa, and the tensile strength was measured 40–85 MPa. From the dynamic mechanical analysis it was also found that storage modulus at rubbery plateau region increased as PEG was introduced up to 16 mol%, indicating a good dimensional stability above Tg.