Data from: Facile Mechanochemical Cycloreversion of Polymer Cross-linkers Enhances Tear Resistance

The mechanical properties of covalent polymer networks often arise from the permanent end-linking or cross-linking of polymer strands, and molecular linkers that break more easily would likely produce materials that require less energy to tear. We report that cyclobutane-based mechanophore cross-linkers that break via force-triggered cycloreversion lead to networks that are up to 9 times tougher than conventional analogs. The response is attributed to a combination of long, strong primary polymer strands and cross-linker scission forces that are ~ 5-fold smaller than control cross-linkers at the same timescales. 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.