Polyesteramide (PEA(n

x/y))prepolymers with Mn from 4400 to 6400 were synthesized through melt polycondensation from adipic

butanediol and N

N′bis(2hydroxyethyl)oxalamide(0)or N

N′-bis(2-hydroxyethyl)adipamide (4)at different butanediol(x)to bisamidediol(y)molar ratios.Chain extension reaction was performed with 2

2′-(1

4-phenylene)-bis(2-oxazoline)(PBOX)and adipoyl biscaprolactamate(ABC)as combined chain extenders.High molecular weight PEA(n

x/y) with Mn up to 22500 and Mw up to 53100 was prepared.The PEA(n

x/y) prepolymers and the chain extended PEA(n

x/y) were characterized by FTIR and 1H-NMR spectroscopy

differential scanning calorimetry(DSC)

and thermogravimetric analysis(TGA).1H-NMR spectra revealed that during the preparation of the PEA(n

x/y) prepolymers

some ester-amide exchange side reaction took place.DSC studies indicated that after chain extension the Tm and ΔHm of the polyesteramides decreased.TGA studies showed that after the chain extension

the thermal stability of the PEA(n

x/y)s slightly decreased

but still a little higher than that of poly(butylene adipate).