Soybean Oil-Based Polyurethane Networks: Shape-Memory Effects and Surface Morphologies

Vegetable oil-based shape-memory polyurethane networks are an emerging class of bio-based functional materials with great potential applications. In this study, a series of different structural soybean oil polyols were synthesized, and utilized to fabricate polyurethane networks by reacting with 1,6-diisocyanatohexane. The soybean oil-based polyurethanes (SOPUs) were characterized with differential scanning calorimetry (DSC), dynamic mechanical tests (DMA), tensile testing, shape-memory testing, and atomic force microscopy (AFM). It was found that SOPUs with a preserved triglyceride structure were fixed in a temporary shape at −20 °C, while others were fixed in temporary shapes at 4 °C. Although the recovery speeds were different, all the samples could completely regain their permanent shapes at 37 °C (human body temperature). Furthermore, different SOPUs exhibited different surface structures, which might provide the materials with additional values.