Extremely Stretchable Vitrimers

Vitrimers are covalent adaptable networks, having many interesting versatile abilities with unprecedented potentials. Here, the combination of a low‐Tg polymer system with dioxaborolane metathesis is used to develop catalyst‐free vitrimers that can be stretched to more than 8900× their original length at a moderate stretching rate (≈50 mm min−1). Superstretchable vitrimers are prepared from biodegradable xylitol‐based polyol oligomers and cross‐linked by dioxaborolane linkages. They are also found to be remarkable in terms of mechanical strength and other properties, such as malleability, self‐healing ability, puncture resistance, and processing stability. Furthermore, the repeated rearrangements of dioxaborolane linkages and hydrogen bonds give rise to efficient energy dissipation with a maximum efficiency of 88%, allowing the superstretchable vitrimers to be promising for energy absorbing applications.