Cationic UV-Curing of Shape Memory Biobased Polyurethanes Sensing Low Heat

The environmental problems caused by thermal reactions have prompted the search for new approaches. Photochemical curing, which uses light energy, offers a sustainable solution for polymerizing complex polymers, reducing energy consumption, and emissions. Current study involves cationic UV-curing of biobased polyurethanes (PU) with a thermo-responsive shape memory behavior on very low temperature almost equal to human body temperature. This product has a potential to be utilized as drug carrier or related biomedical applications, as well as self-tightening materials against human body heat. Polymer has been designed from sesame oil, with slight modification through a facile epoxidation approach. Main objectives of this research were to prepare biobased PU recipe; to utilize a specially designed UV-curing approach for this synthesis; and to develop shape memory properties upon sensing human body temperature. Prepared material has been analyzed through FTIR, SEM, TGA, DSC, water absorption capacity (WAC), and gel contents (GCs). Shape memory behavior has been tested in both air and water against a range of temperatures (35 degrees C-80 degrees C). At 35 degrees C in 208 s, prepared sample, presented 96.60% Rr and 90.56% Rf, whereas at 80 degrees C in 55 s Rr increased to 98.33% and Rf increased to 100%. Hydrophobic nature of sample was confirmed by 4.1% water absorption in 48 h.