Green synthesis of polyhydroxyurethane and characterization of its blend films with polycaprolactone

In this thesis, environmentally friendly polyhydroxyurethane polymers were successfully synthesized through a green chemistry approach without the use of isocyanates. These polymers were then incorporated into a biodegradable polyester matrix, polycaprolactone, to produce composite films. The monomer diglycerol dicarbonate was synthesized and reacted with 2,2,4-trimethylhexamethylene diamine and a crosslinker, tris(2-aminoethyl) amine, under solvent-free conditions, aiming to minimize environmental impact. Composite films containing 5%, 10%, and 15% polyhydroxyurethane by weight were prepared, and their chemical, thermal, mechanical, and surface properties were comprehensively characterized using FT-IR, DSC, TGA, SEM, contact angle measurements, tensile testing, and swelling test. The results indicated that the addition of polyhydroxyurethane significantly enhanced the hydrophilic character of the inherently hydrophobic polycaprolactone matrix, while low polyhydroxyurethane content (5%) also improved tensile strength without compromising flexibility. Thermal analyses showed that polyhydroxyurethane restricted polycaprolactone crystallization and introduced a multi-step degradation behavior, offering potential for thermal performance tuning. In conclusion, polyhydroxyurethane/polycaprolactone composite films synthesized via green chemistry exhibited promising properties for potential use in biomedical applications such as wound dressings. The findings of this study demonstrate the potential of isocyanate-free polyurethane systems as sustainable alternatives and highlight the need for further research in this direction.