## 1 Introduction  
The reactivity of olefins found in natural oils has been widely exploited as a means of preparing novel polymers with a high proportion of the carbon derived from renewable resources. Besides well-known drying oil technologies [1], various chemical modifications of triglycerides have been explored in order to improve reactivity and access a wider range of materials with desirable properties and functional performance. One strategy has been to apply catalytic isomerization to increase conjugation of polyunsaturated fatty chains. For example [PERSON] _et al_. have developed a Rh-catalyzed process that yields raw materials that are well suited for free radical and ring-opening metathesis polymerizations [2, 3]. Unsaturated fatty chains may also be converted to epoxides, which may be used in curing chemistries directly or further modified with reactive maleic or acrylic functionality [4]. The latter, in the form of acrylated epoxidized soybean oil (AESO, representative structure shown in Figure 1A) has been extensively developed as the foundation for a range of bio-based polymer and composite materials: AESO has been copolymerized with numerous petroleum-derived monomers such as alkyl acrylates and methacrylates, vinyl alcohol, vinyl acetate, acrylic acid, and styrene, in thermosetting reactions promoted by free radical initiators. The resulting materials vary widely depending on the blending ratios, cure cycles, and properties of the comonomer [5]. The 12 Principles of Green Chemistry call for use of renewable resources whenever practicable [6, 7], therefore recent work has focused on maximizing the bio-based content in triglyceride-derived polymer systems. Prospective biorefinery products from carbohydrates [8, 9] and lignin [10] are interesting as potential feedstocks for further development of AESO chemistry. For example, [PERSON] _et al_. have shown that lignin model compounds with reactive functionality can provide similar properties and functional performance as styrene in thermosetting systems [11, 12]. Rosin acids have also been explored as potential alternatives to styrene or divinylbenzene [13].  
In this study, we polymerized AESO with bio-based comonomers to produce novel thermoset materials. Dibutyl itaconate (Figure 1B) was selected as one of the comonomers due to its structural similarity to acrylates and methacrylates, lower toxicity, and the status of itaconic acid as one of the US DOE \"Top 10\" chemical opportunities from biomass [9]. As itaconic acid is readily derived from carbohydrates _via_ fungal fermentation, it has been successfully used in a variety of polymer applications [14]. These include as a dienophile for Diels-Alder chemistry in modification of fatty  
Figure 1: **(A)** Representative structure of acrylated epoxidized soybean oil (AESO); **(B)** dibutyl itaconate; **(C)** ethyl cinnamate.  
acids [15], grafting of polyitaconic acid onto other polymers [16], and incorporation into epoxy resins [17]. We also studied ethyl cinnamate (Figure 1C) as a lignin model compound, to determine whether the cinn amyl moieties found in native or isolated lignins (and potentially in bio- oils as well) are reactive with AESO. Dibutyl itaconate and ethyl cinnamate were incorporated into thermoset materials with AESO at various ratios and we report the resulting spectral, thermal, and mechanical properties.