Synthesis of Poly(ether‐ester‐urethane) with a Controlled Molar Mass Based on Poly(ε‐caprolactone) and Poly(ethylene glycol) Segments

Abstract

AbstractPoly(ether‐ester‐urethanes) (PEEUs) derived from poly(ε‐caprolactone) and poly(ethylene glycol) (PCL‐b‐PEG) have a high potential for use in biomedical applications or as compatibilizers of immiscible poly(acid lactic) and poly(ε‐caprolactone) (PLA/PCL) blends. This study focused on the synthesis of PEEUs with same molar mass by one‐step bulk polycondensation of PCL and PEG macrodiols and hexamethylene diisocyanate (HDI). The copolymers, distinguished by the size of hydrophilic PEG and hydrophobic PCL segments and symmetry of the blocks, are characterized by SEC, FTIR, H1‐NMR, TGA, DSC, and water absorption testing. FTIR and H1‐NMR results demonstrated the formation of a hydroxy‐terminated multiblock copolymer with urethane bonds. Additionally, the PEG:PCL compositions measured by H1‐NMR are close to the theoretical compositions. Molar mass distribution curves revealed that copolymers with molar mass around 45 000 Da are synthesized by varying extents of ratio, given by NCO/OH molar ratio, between 0.9 and 1.0 depending on the initial macrodiols molar masses. The block size ratio of hydrophilic and hydrophobic blocks is an important parameter in water absorption behavior, which can generate a water‐uptake of 50% or even 350% depending on the symmetry of the segments.