Environmental concerns and the need for sustainable industrial practices have sparked the search for alternative materials that offer a lower impact on the environment. Over the course of the past few decades, numerous bio‐based polymers have been developed from natural resources. Among the materials, bio‐based thermosets are of particular interest due to their increased thermal stability in comparison to thermoplastics. This review covers recent advancements made in the field of bio‐based thermosets, with a special focus devoted to resins prepared from vegetable oils, natural phenolic compounds and a selection of other thermosetting systems developed recently based on either the polymerization of multifunctional monomers or the crosslinking of linear systems. This review article concludes with a critical perspective on the environmental implications of bio‐based thermosets. © 2020 Society of Industrial Chemistry

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Natural polymers, such as starch, and polymers derived from renewable resources, such as vegetable oils, have been considered as alternatives to petroleum-based plastics during recent decades, due to environmental concerns. Indeed, these materials can offer a variety of advantages, such as low cost, wide availability, carbon neutrality, elevated thermal stability, and easily tunable mechanical properties. However, some of these polymers alone exhibit poor mechanical properties, making them not suitable for some applications. Hence, the reinforcement of these bio-based polymers with other materials is often considered to overcome this challenge. In this work, thermosetting composites based on tung and linseed oil resins were prepared using starch as reinforcement. Analyses from Soxhlet extractions showed that the higher the concentration of tung oil in comparison to linseed oil in the resins, the lower the mass of unreacted material, leading to an optimum resin entirely based on tung oil. Dielectric analysis (DEA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) indicated that the polymerization was completed in 3 h 20 min, at 140 °C, and that the composites were thermally stable until 270 °C. Finally, dynamic mechanical analysis (DMA) confirmed that the addition of starch to the resins increased the room temperature storage modulus (E’25) from 94 MPa to 893 MPa. Composites prepared with a resin formulation that did not contain a compatibilizer exhibited E’25 of 441 MPa. The composites investigated in this work are promising candidates for applications that require improved mechanical properties.

Sustainable and renewable polymeric materials are gaining traction, and vegetable oils have been used directly or in modified forms to meet this demand. At the same time, microbial hosts (such as the oleaginous yeast Yarrowia lipolytica) are being touted as sustainable alternatives for petroleum and vegetable oils. However, the exact role of fatty acid composition and speciation on polymer performance remains unclear. Here, we explore a datadriven approach to explicitly relate the underlying oil composition with the thermomechanical properties of the resulting polymeric material. In doing so, we identify the C16:0, C16:1, and C18:0 fatty acid contents of vegetable oils as critical parameters for predicting thermal stability at maximum heat loss (T max ). Machine learning-based approaches were applied to study the link between thermal properties and monomer composition. In the end, application of multiple linear regression modeling indicated strong dependence on the C16:1 content as evident by the parameter loading (loading of +428 for T max ). As a more sustainable source of oil, Y. lipolytica oil-based polymer properties were also dictated by the C16:0 and C18:0 fatty acid contents but with an opposite impact as compared with vegetable oils (T max loadings of −208 and +36 for Y. lipolytica oils, +19 and −72 for vegetable oils, C16:0 and C18:0, respectively). Despite these differences, Y. lipolytica oilbased polymers showed similar strength and cross-linking density to vegetable oil polymers. This work is the first evaluation of polymer properties from a library of vegetable-and yeast-sourced oils and highlights a mechanistic understanding of thermal stability from both oil source (vegetable or microbial) and oil composition that can be used for future design.

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