Conclusion
In summary, we successfully synthesized three hyperbranched structures with a common Si-O-C molecular backbone but differing terminal groups. These structures were co-crosslinked with thermoset epoxy to explore their terminal effects on affecting the overall material performance. The special molecular characteristics of HBPSi-R involves abundant -OH groups for their reactiveness, as well as distinctive terminals (-NH2, -EP, vinyl groups) that impart characteristic interface features. All three variants of HBPSi-R exhibit well compatibility within the epoxy matrix, showcasing diverse nano-interface and aggregation behavior. Benefiting their spatial molecular configuration and flexible Si-O-C branches, HBPSi-R manifests exceptional strengthening and toughening effects regardless of their terminal groups. Among them, HBPSi-NH2 predominantly exhibits the aggregation behavior from supramolecular interaction, while HBPSi-EP show predominantly exhibits dispersion behavior from covalent effect. HBPSi-V achieves a balance of the both, surpassing the other two structures in terms of optimal impact toughness (28.9 kJ mol-1) and better mechanical performance under high dosage, where the non-reactive vinyl group acts as a supportable role during polymer crosslinking. These findings not only emphasize the pronounced reinforcement effects of HBPSi-R but also provide a fresh perspective from aggregate science in the context of polymer crosslinking.