## 3 Results and Discussion
### Thermal Stability
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Sample** & **AESO: EC, 1:1** & **AESO: EC, 2:1** & **AESO: EC, 3:1** & **AESO: DBI, 1:1** & **AESO: DBI, 2:1** & **AESO: DBI, 3:1** \\ \hline \(T_{\mathrm{g}}\) (as Tan \(\delta\) peak, \({}^{\circ}\)C) & 14.2, 15.6 & 21.0, 21.1 & 41.4, 36.3 & 1.4, 2.5 & 18.4, 19.2 & 27.3, 25.4 \\ Storage modulus E’ & 6.5, 9.1 & 16.6, 13.7 & 35.2, 37.0 & 1.5, 1.6 & 6.6, 7.1 & 17.8, 10.2 \\ (at 30 \({}^{\circ}\)C, MPa) & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Glass transition and viscoelastic properties of AESO blends (Each measurement was made on two different samples). Figure 8: Tan \(\delta\) as a function of temperature for AESO-EC thermosets. The \(T_{\rm g}\) of AESO homopolymer depends on the degree of acylation; a typical value is about 47 \({}^{\circ}\)C [5]. In this study, lower values were observed as the amount of EC or DBI increases; this can be attributed to lower cross-link density as both DBI and EC can only serve as linear chain extenders. The \(T_{\rm g}\) of DBI homopolymer is 14.7 \({}^{\circ}\)C [24]. Since we observe \(T_{\rm g}\) values as low as 1-2 \({}^{\circ}\)C for AESO-DBI polymers, lower than the \(T_{\rm g}\) of DBI or AESO homopolymers, the copolymer shows a strong plasticizing effect. Interestingly, this is the opposite of the effect reported in an AESO-methyl methacrylate system [25]. In the case of the 1:1 AESO-EC blend, the presence of unreacted liquid EC is likely reducing the glass transition temperature. However, in all cases the observed \(T_{\rm g}\) values are slightly higher than those seen for the AESO-DBI blends, suggesting that the aromatic content of the copolymer provides some rigidity. The experimental results are in good agreement with the Twinkling Fractal Theory of the glass transition, which has been extensively used to model the properties of polymers based on acylated oils [26, 27]. Storage modulus (E') values for both AESO-DBI and AESO-EC samples were substantially lower than that of pure AESO which is about 320 MPa at 30 \({}^{\circ}\)C. This is consistent with the rubbery nature of the materials which are above or near the glass transition point at room temperature. The modulus values decrease with decreasing AESO content due to the lower crosslink density. In other studies of AESO blends, decreased E' values have been seen for comonomers such as methacylated lauric acid (100 MPa at 30 \({}^{\circ}\)C), whereas styrene blends provide significant increases (typically \(>\)1 GPa at 30 \({}^{\circ}\)C) [21]. Based on the known properties of related thermoset systems, triglyceride-based copolymers with DBI and EC could be obtained with higher \(T_{\rm g}\) and modulus values through two strategies. First, increasing crosslink density could be achieved by working with starting oils having a higher degree of unsaturation (for example, linseed oil), leading to a higher proportion of reactive acrylate groups after derivatization. Crosslink density can also be increased through maleic anhydride modification of residual OH groups, so the resulting monomers (MAESO) have additional reactive sites [5]. Second, incorporation of fibers into AESO-based resins is known to improve mechanical performance. Renewable resources such as keratin, chicken feathers, and sisal have been recently reported for such a purpose [28, 29, 30].