Linear dependence of iodine value on the mass fraction of vegetable oils: a new way to overcome seasonal challenges for renewable polymer manufacturing

Polymers derived from non-renewable sources are prevalent today. The demand for environmentally sustainable alternatives, such as vegetable oils, is consequently increasing. However, the large-scale utilization of vegetable oil in the polymers production is hindered by seasonality and regional availability. To address these challenges, this study demonstrates the feasibility of creating vegetable oil blends with precise iodine values (IVs), a critical parameter for polymerization. These blends exhibit a linear relationship between IV (determined by both titration and ¹H-NMR methods) and mass fraction. By combining vegetable oils with varying IVs, blends can be used to achieve the desired unsaturation level providing a continuous supply of raw materials for the polymer industry. Thus, to validate this approach, a polymer was synthesized using a blend of Brazil nut and linseed vegetable oils, resulting in an IV equal to 123.5 g of I₂ per 100 g of sample. This polymer exhibited comparable properties, including thermal stability (265 °C) and glass transition temperature (-14.7 °C), to a polymer made from pure grape seed oil with an IV of 123.0 g of I₂ per 100 g. These findings confirm that the desired IV can be achieved through simple blending based on a linear relationship between IV and mass fraction. Therefore, this approach enables the production of polymers with properties similar to those obtained using a single vegetable oil, thereby expanding the potential for sustainable polymer manufacturing.