A photo-reversible crosslinking resin for additive manufacturing: reversibility and performance.

Improving the adhesion between layers and achieving the recycling of resins are challenges in additive manufacturing (AM) technology. In this work, a new type of photo-reversible crosslinking resin based on polyvinyl alcohol (PVA) and coumarin (HMC) was prepared via grafting reaction. The critical idea was to create a coumarin based photo-reversible crosslinking resin by carefully tailoring the photo-crosslinking time and temperature, so that the resin could be extruded through the nozzle and then maintain the proper shape during UV-curing. Photo-reversible crosslinking of AM resin was realized without the use of monomers, photo-initiators or propagating. A reasonable irradiation time with 354 nm (crosslink) or 254 nm UV light (cleavage) of 10 min was critical for photo-reversible crosslinking of PVA- g -HMC at 120 °C. An important result of this work was that the developed photo-reversible crosslinked resin could be reused and the printed resin exhibits excellent adhesion properties, thermal conductivity and oxygen barrier performance.