Hydrophilic poly(ether-ester)s and poly(ether-ester-amide)s derived from poly(ε-caprolactone) and -COCl terminated PEG macromers

A series of poly(epsilon-caprolactone) (PCL)-based multiblock poly(ether-ester)s (PEE)s and poly(ether-esteride)s (PEEA)s were obtained from alpha,omega-dihydroxy-PCL ((M) over bar (n) = 2-4- kDa) and -COCl di-terminated poly(ethylene oxide) (PEO) macromers (MAC) of different length ((M) over bar (n) = 150, 300, 600, 1000 Da). 4,7,10-Trioxa-1,13-trideca-nediamine was used in the synthesis of PEEAs. Bulk poly-condensation processes were accomplished by one step (PEE) and two step (PEEA) procedures. PEEAs with PCL/MAC/Trioxy molar ratios 1:2:1 and 1:12 were investigated. The multiblock copolymer architecture was proved by H-1 NMR and size exclusion chromatography (SEC) techniques. Unimodal molecular weight (MW) distributions and (M) over bar (n) values in the range of 13.3-21.0 kDa (PEE) and 8.1-12.8 kDa (PEEA) were found. Crystalline PCL-type phases were identified for both PEEAs and PEEs by X-ray diffraction. The thermal transitions were investigated by differential scanning calorimetry (DSC). The T-m values (49.9-53.4degreesC) reflect those of the PCL component while the T-g of PEEAs (-45 to -52degreesC) are higher than those of the PEEs (-58 to -61 degreesC) or the macromers. The equilibrium water uptakes range from 1.0 to 18.4 wt.-% (PEE) and from 4.4 to 8.8 wt.-% (PEEA) depending on both the composition and length of the ethylene oxide sequences. A dependence of surface homogeneity on copolymer composition was found for PEEs by dynamic contact angle measurements.