TIT# Nanostructural Features of Novel Random Polyester-amide Copolymers
     as Revealed by X-ray Scattering and Microindentation Hardness
AUT# Flores, A.; Pietkiewicz, D.; Stribeck, N.; Roslaniec, Z.;
     Baltá Calleja, F. J.;
SOU# Macromolecules (2001), 34, 8094-8100
LOC# xv058
CLA#
COM#
APP#
MAT#
ABS# The correlation between nanostructure, as derived by X-ray scattering,
     and the micromechanical properties, as revealed by microindentation
     hardness, of a series of novel random ester-amide copolymers, based on
     butyl terephthalate and an etherdiamide, has been investigated. The
     interface distribution function has been used for the analysis of the
     small-angle X-ray data. The influence of the etherdiamide content and
     the number of the flexible groups in the etherdiamide unit on the
     nanostructure of the copolyester-amides is discussed. Hardness is shown
     to be a property critically dependent on the number of etherdiamide
     sequences within the copolymer chains. The hardness values of the
     copolyesters appear to deviate from the linear additivity law. This
     deviation seems to be mainly due to a contribution of several factors:
     (i) the lower hardness value of the poly(butyl terephthalate) (PBT)
     amorphous segments within the copolymer with respect to that of the PBT
     homopolymer; (ii) an increase in the surface free energy of the PBT
     crystals with increasing etherdiamide content; (iii) a decrease in the
     energy required for the mechanical deformation of the PBT crystals with
     increasing etherdiamide content and increasing number of flexible groups
     within the etherdiamide unit.