S3.1. Calculation of network crosslinking density
Based on the rubber elasticity theory, the crosslinking density can be calculated using the equation (2), with the results listed inTable S2 and Figure 5b .
\begin{equation} d_{\text{crosslink}}=\frac{E^{\prime}}{[2(1+\gamma)RT]}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ (2)\ \nonumber \\ \end{equation}
Where E’ is the rubbery plateau storage modulus atTg + 40 oC; γ represents the Poisson’s ratio that is assumed to be 0.5 when the crosslinked network is incompressible for thermoset; R and T represent the gas constant and the Kelvin temperature, respectively. Note that the equation is applicable for lightly crosslinked materials and therefore is used only to qualitatively compare the crosslinking level in the casting resins.[7, 8]
Table S2 Some parameters obtained from DMA results