Synthesis of New Environmentally Friendly Polyurethanes: the Effect of Vegetable oil Content on Shape Memory Behaviour

The 21st century is known for using natural resources as environmental consideration in the field of polymer science. In the presented study, vegetable oil-based polyurethanes were synthesized using a mixed polyols component with poly (ε-caprolactone) diol (PCL3000)/ Castor oil by reacting with 1,6-diisocyanatohexane. The effect of Castor oil molar ratios on the structure, physical-chemical properties, mechanical and shape memory behaviour was investigated by means of Fourier-transform spectroscopy (FT-IR), dynamic mechanical thermal analysis (DMTA), tensile testing and shape-memory testing, respectively. FTIR confirmed the formation of chemical structure of the synthesized polyurethanes. It also indicates that by increasing castor oil content in the soft segment an increase in segments mixing was occur. DMTA studies showed the effect of two synergistic parameters including dangling chains and cross-link networks of Castor oil on the storage modules. A gradual increase in tensile strength and modulus with an increase in chemical cross-links in the polyurethane structure, up to the PU with a 50/50 ratio of PCl/Castor oil can be observed compared to the pure polyurethane. An excellent shape recovery up to 96% was observed for the Castor oil-based polyurethanes. Thus, petroleum polyols could be successfully replaced by vegetable oil and mechanical properties as well as shape memory properties were improved

کلیدواژه ها:

Polyurethane ، Vegetable oils ، Smart polymers. Shape memory properties