## 2 Experimental
### Characterization  
In order to determine the optimum curing time, dielectric analysis (DEA) experiments were conducted with an Epsilon DEA 230/1 cure monitor (Netzsch Instruments North America LLC, Burlington, MA, USA) equipped with a flexible probe that was immersed in the resin during curing. After the cationic process initiated at room temperature while the sample rested for 30 min, the cure was completed in a convection oven kept at 140 \({}^{\circ}\)C. That temperature was chosen based on the cure of related systems [11,30], and preliminary tests with the resin composition reported here. As a matter of fact, it has been previously shown that soybean oil-based cationic composites reinforced with continuous glass fibers were successfully cured over the course of 10 h at 110 \({}^{\circ}\)C after a 30 min pre-heating time [30]. A slightly higher temperature was chosen with the goal of reducing cure time and due to differences in the resin composition in comparison to previously studied systems [30]. The DEA tests were run for 12 h with frequencies ranging from 0.3 to 10,000.0 Hz. The permittivity and loss factor of the samples were measured as a function of time. The results presented in the text correspond to a plot of ion viscosity (\(\Omega\) cm) _vs._ time for a \(\sim\)10 g sample.  
Differential Scanning Calorimetry (DSC) experiments were conducted with a Q20 DSC instrument (TA Instruments, New Castle, DE, USA). Samples of \(\sim\)10 mg were heated, under a N2 atmosphere, from \(-\)30 to 200 \({}^{\circ}\)C at a heating rate of 10 \({}^{\circ}\)C min\({}^{-1}\). Thermogravimetry (TG) experiments were performed on a Q50 thermobalance (TA Instruments, New Castle, DE, USA) with samples of approximately 10 mg, under an air atmosphere, from room temperature to 650 \({}^{\circ}\)C, at a heating rate of 20 \({}^{\circ}\)C min\({}^{-1}\).  
A Q800 DMA (TA Instruments, New Castle, DE, USA), with a tension fixture, was used for all dynamic mechanical analysis (DMA) experiments. Samples were cut into 23.0 mm \(\times\) 10.0 mm2.2 mm (length \(\times\) width \(\times\) thickness, respectively) specimens. The specimens were heated from \(-\)60 to 150 \({}^{\circ}\)C, at a heating rate of 3 \({}^{\circ}\)C min\({}^{-1}\), in iso-strain mode, with a frequency of 1 Hz, and amplitude of 14 \(\upmu\)m. The experiments were repeated to ensure consistency, and the results presented here reflect the average of two measurements that only differ by a maximum of 10%. The \(T_{\rm g}\) values reported in this manuscript were determined based on the peak maxima of the tan \(\delta\) curve of each sample.  
Composite samples of 1-3 g underwent Soxhlet extraction for 24 h with dichloromethane. The solvent was removed from the extracts using a rotary evaporator. Soluble and insoluble materials were dried in a vacuum oven at 70 \({}^{\circ}\)C overnight. After weighing the recovered materials, the soluble portions were dissolved in deuterated chloroform for proton nuclear magnetic resonance (\({}^{1}\)H NMR) spectroscopy analysis. The \({}^{1}\)H NMR spectra were obtained on an Agilent MR400 DD2 spectrometer (Santa Clara, CA, USA) operating at 400 MHz.