MIT News June 22, 2023
Tough materials can sustain substantial subcritical damage without complete failure of the material, but trying to improve toughness can often lead to the degradation of other mechanical properties. Researchers at Duke University developed cyclobutane-based mechanophore cross-linkers that broke through force-triggered cycloreversion led to networks that were up to nine times as tough as conventional analogs. The response was attributed to a combination of long, strong primary polymer strands and cross-linker scission forces that were approximately fivefold smaller than control cross-linkers at the same timescales. According to the researchers the enhanced toughness comes without the hysteresis associated with noncovalent cross-linking, and it is observed in two different acrylate elastomers, in fatigue as well as constant displacement rate tension, and in a gel as well as elastomers… read more. TECHNICAL ARTICLEÂ
As this polymer network is stretched, weaker crosslinking bonds (blue) break… Credits: The researchers, edited by MIT News