SYNTHESIS OF POLYESTERAMIDES FROM N,N′-BIS(2-HYDROXYETHYL)TEREPHTHALAMIDE AND CHAIN EXTENSION REACTION

Polyesteramide (PEA (x/y)) prepolymers with intrinsic viscosity from 0.24 dL/g to 0.52 dL/g were synthesized through melt condensation polymerization from adipic acid, butanediol and N,N'-bis(2-hydroxyethyl)terephthalamide (HETA) at different butanediol (x) to HETA (y) molar ratios. Chain extension reaction was performed with 2,2'-(1,4-phenylene)-bis(2-oxazoline) (PBOX) or adipoyl biscaprolactamate (ABC) alone, or with combined PBOX + ABC chain extenders. High molecular weight PEA with Intrinsic viscosity of 1.05 and 0.73 dL/g was obtained when PEA (90/10) and PEA (80/20) prepolymers were chain extended. The PEA prepolymers and the chain extended PEA were characterized by FTIR and H-1-NMR spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). H-1-NMR spectra revealed that during the preparation of PEA prepolymers,ester-amide exchange side reaction took place. DSC studies indicated that after chain extension, the T-g of PEA (80/20) increased, and its Delta H-m as well as T-m decreased. PEA (0/100) is a non-crystallizable polyesteramide, and its T-g is 65 degrees C. TGA studies showed that as the content of HETA used in the synthesis of PEA (x/y) prepolymers increased, the thermal stability of the prepolymers decreased because the introduced terephthalic diesterdiamide showed less stability.