Abstract
Waterborne polyurethane (PU) based on poly(ε-caprolactone) (PCL) diol and an amphiphilic polylactide-poly(ethylene glycol) (PLA-PEG) diblock copolymer was synthesized. The molar ratio of PCL/PLA-PEG was 9:1 with different PLA chain lengths. The PU nanoparticles were characterized by dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and rheological analysis. The water contact angle measurement, infrared spectroscopy, wide angle X-ray scattering (WAXS), thermal and mechanical analyses were conducted on PU films. Significant changes in physio-chemical properties were observed for PUs containing 10 mol % of amphiphilic blocks. The water contact angle was reduced to 12°–13°, and the degree of crystallinity was 5%–10%. The PU dispersions underwent sol-gel transition upon the temperature rise to 37 °C. The gelation time increased as the PLA chain length increased. In addition, the fractal dimension of each gel was close to that of a percolation cluster. Moreover, PU4 with a solid content of 26% could support the proliferation of human mesenchymal stem cells (hMSCs). Therefore, thermo-responsive hydrogels with tunable properties are promising injectable materials for cell or drug delivery.
Highlights
Polyurethanes (PUs) are polymers mainly consisting of long chain oligodiol as the soft segment and diisocyanate as the hard segment, in which short chain diol or diamine is added, serving as a chain extender
Four types of waterborne PUs based on 90% PCL diol and 10% amphiphilic polylactide-poly(ethylene glycol) (PLA-poly(ethylene glycol) (PEG))
The prepared PUs, PU1–PU4, showed significantly different properties from PU0 consisting of 100% PCL as soft segments
Summary
Polyurethanes (PUs) are polymers mainly consisting of long chain oligodiol as the soft segment and diisocyanate as the hard segment, in which short chain diol or diamine is added, serving as a chain extender. The process of synthesizing waterborne PU is more eco-friendly, and water-based PUs are more favorable compared to conventional PUs. The commonly-applied approach to uniformly disperse PU particles in an aqueous solution is the incorporation of an ionic chain extender into the chemical structure of PU [2]. Amphiphilic copolymers, which contain both hydrophilic and hydrophobic parts, have drawn much attention for biomedical applications in the past few decades. One category of these block copolymers consists of polylactide and poly(ethylene glycol) (PEG). PEG is highly hydrophilic and biocompatible and provokes less immune responses [4].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
