## 2 Experiment
### The Blending and Curing of BADPE with BAFDCy/BADCy/BEDCy
The 0.3% Cu(acac)\({}_{2}\)-catalyzed curing of BADPE with BAFDCy/BADCy/BEDCy, and its thermal stability study  
Using the above method, after equimolar blending of the synthesized bisphenol A dipropargyl ether with the cyanate ester, the curing reaction of the blend resins was catalyzed by the addition of Cu(acac)\({}_{2}\) with a mass fraction of 0.3%, and the DSC analysis of this is shown in Figure 7. It can be seen that the final temperature of the curing reaction of the three hybrid resins was lower than 473 K. The curing process of the three hybrid resins was determined to be 363 K/2 h + 433 K/2 h + 473 K/4 h.  
The initial temperature, peak temperature, and final temperature of the blended resin were lower than those of the pure resin, T\({}_{\rm i}\) was 67 K lower and T\({}_{\rm p}\) was 45 K lower than that of BADCy, and the exothermic peak of the blended resin's cure was widened. This \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Mass Fraction/\%** & **T\({}_{\rm i}\)/K** & **T\({}_{\rm p}\)/K** & **T\({}_{\rm f}\)/K** & **\(\Delta\)H/(J**\(\cdot\)g\({}^{-1}\))** \\ \hline
0.1 & 426.15 & 444.15 & 493.15 & 403 \\
0.2 & 411.15 & 433.15 & 458.15 & 389 \\
0.3 & 408.15 & 427.15 & 448.15 & 396 \\
0.5 & 404.15 & 423.15 & 444.15 & 410 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Results of BAFDCý curing catalyzed by different mass fractions of copper acetylacetonate. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Cyanate** & **T\({}_{\rm i}\)/K** & **T\({}_{\rm p}\)/K** & **T\({}_{\rm f}\)/K** & **\(\Delta\)H/(J**\(\cdot\)g\({}^{-1}\))** \\ \hline BADCy & 520.15 & 563.15 & 628.15 & 871 \\ BADCy + 0.3\% Cu(acac)\({}_{2}\) & 398.15 & 444.15 & 491.15 & 526 \\ BEDCy & 459.15 & 502.15 & 533.15 & 834 \\ BEDCy + 0.3\% Cu(acac)\({}_{2}\) & 409.15 & 450.15 & 484.15 & 734 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results of DSC analysis of the copper acetylacetonate-catalyzed curing reaction of cyanate esters. Figure 7: DSC plots of the catalytic curing of three hybrid resins. indicates that the curing temperature of BADCy can be reduced by blending BADCy with BADPE and then curing. After the addition of the catalyst, the curing reaction temperature T\({}_{\rm i}\) decreased significantly, and the curing reaction peak temperature also changed from one to three, indicating that the curing reaction of the blended resin changed with the addition of the catalyst. The highest peak curing temperature of the blended resin, which should be the temperature at which the free radical polymerization and cross-linking of chromene occurs, did not decrease much with the addition of the catalyst, and so did the temperature at which the catalyst catalyzes the cyanate ester trimerization and cyclization reaction. The significantly lower first peak temperature is the temperature at which the catalyst catalyzes the cyclisation of the propargyl ether and the linear polyene oligomerization reaction, the intermediate peak temperature belongs to the rearrangement reaction of the propargyl ether and is the temperature at which the ether oxygen atom catalyzes the cyanate ester triple cyclisation reaction, and the final peak temperature is the temperature at which the free radical polymerization of the alkene bond takes place. To investigate the thermal stability of three hybrid resin systems cured by Cu(acac)\({}_{2}\)-catalyzed curing, thermogravimetric analysis (TGA) was used as a research tool, as shown in Figure 8. In contrast, the hybrid resin cures of the bisphenol A dipropagryl ether prepolymer and the three cyanate esters showed different residual rates (Yr873 K) of 35.9%, 37.9%, and 0.7%, respectively, in the air system at 873 K. The cures of the bisphenol A dipropagryl ether prepolymer and the three cyanate esters were found to be more stable in the air system.