Thermally Reversible Diels-Alder Bond-Containing Acrylate Networks Showing Improved Lifetime

Photopolymerization of (meth)acrylates into highly crosslinked networks is in general accompanied by volumetric shrinkage, often leading to premature material failure. In this work, thermoreversible Diels-Alder groups are investigated to explore their effect on material lifetime. A difunctional acrylic monomer containing Diels-Alder moieties is synthesized and successfully incorporated in a polymer network by photopolymerization. It is demonstrated that upon heating above 150 degrees C, the Diels-Alder bonds open, yielding topological rearrangements of the network. The mechanical properties of the material after opening of the Diels-Alder moieties are investigated by tensile testing, showing a high strain-rate dependence of the yield stress which is indicative of a longer lifetime at the higher strain rates that are prevalent in load-bearing applications.