Abstract
A series of random polyesteramides (PEAs) were obtained by direct reaction of epsilon-caprolactone and B-alanine in the melt and a quasi-alternating polyesteramide (degree of randomness = 1.63) was synthesized by melt polycondensation of an intermediate hydroxy- and ethyl ester-terminated amide. Model reactions show that the reaction between epsilon-caprolactone and B-alanine proceeds first by the ring opening of epsilon-caprolactone by the amine groups of beta-alanine. The random PEAs with epsilon-caprolactone contents equal to or higher than 60 mol.% present a well-defined endotherm (T-m = 29-56 degrees C) corresponding to CL-rich polymer domains. On the other hand, random PEAs with epsilon-caprolactone content below 60 mol.% present a broad melting zone (T-m = 133-159 degrees C) corresponding to ill-defined beta-Ala-rich polymer domains. The quasi-alternating PEA (epsilon-caprolactone content of 50 mol.%) presents a well-defined and large melting endotherm (T-m = 92 degrees C) and exhibits notably higher Young's modulus and ultimate tensile strength than its random counterpart. (C) 2014 Elsevier Ltd. All rights reserved.