Vegetable Oils-Based PU

However, in this chapter, we will focus the attention on vegetable oil-based PU and on the bio-poly(ester urethane)s as the most common and useful bio-based PU in the main industrial applications. 

Soybean oils (SBO) is the main vegetable oil considered for polyol conversion [61, 62]. However, SBO oil is relatively unreactive in typical polymer formulations and, thus, it must be functionalized. For instance, epoxidized soybean oil (ESBO) has received increased attention for the development of ESBO-based PU [62,63] since the presence of epoxy groups has also a strong effect on the thermal stability of PU [46]. 

PU synthesized through an isocyanate-free method has been recently reported by Besse et al. They obtained linear and branched bio-based PU from isosorbide with acceptable thermal stability suitable for coatings applications. Isosorbide, extracted from the dehydration of sorbitol, as HS provides a good rigidity to the polymer [68]. Moreover, Besse et al. studied new bio-based isocyanate-free PUs with good thermal stability for coatings [68]. These PUs do not release isocyanate during the thermal decomposition. 

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