Sunflower oil based biodegradable hyperbranched polyurethane as a thin film material

The vegetable oil based biodegradable advanced materials with hyperbranched architecture has drawn tremendous attraction in recent years. In the present study, sunflower (Helianthus annuus L) oil modified hyperbranched polyurethane (HBPU) and linear polyurethane (LPU) were synthesized by using toluene diissocyanate, poly(epsilon-caprolactone), butanediol and monoglyceride of oil, with and without pentaerythritol as a multifunctional unit, respectively. The structures of polyurethanes were confirmed by Fourier transformed infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopic and X-ray diffraction (XRD) studies. H-1 NMR study confirmed the hyperbranched structure with degree of branching 0.76 for HBPU. Physico-mechanical properties like impact resistance (90 cm vs. 100 cm), scratch hardness (4.3 kg vs. 4.7 kg), tensile strength (18.9 MPa vs. 23.18 MPa) and elongation at break (750% vs. 700%); biodegradability as tested by broth culture technique using Pseudomonas aeruginosa and Bacillus subtilis strains, and thermal stability (239 degrees C vs. 250 degrees C) were found to be higher for HBPU than LPU. Therefore, the bio-based synthesized HBPU with the desired properties in terms of physico-mechanical, thermal, and biodegradability has the potential to be used as a thin film material for advanced multifaceted applications. (C) 2012 Elsevier B.V. All rights reserved.