Faculty Sponsor's Department:
The ever-increasing problem of petrochemically derived plastic pollution and the inefficiency of recycling polymers constitute some of the significant technological problems of polymeric materials. Such issues have led to the development of advanced self-healing materials called vitrimers that, despite being cross-linked, can exchange bonds upon heating. Vitrimers can be reprocessed with ease and have comparable mechanical properties to pristine, undamaged polymers. This work aims to design a vitrimeric system that can be shaped and polymerized through stereolithographic 3D printing techniques, such as Solution-Mask Liquid Lithography (SMaLL), thus obtaining an object of interest. To render such technology available to the public and commercially competitive, we have developed and optimized the synthesis of acrylate and epoxy monomer systems containing dynamically bonded dioxaborolane cross-links. Tri-functional molecules were reacted with arylboronic acids to produce boronic esters and reacted further to add an epoxy or acrylic terminus to be polymerized in situ cationically or through free-radical polymerization through SMaLL to create materials with isotropic and self-healing properties. Resin formulations, which include the dioxaborolane cross-linkers, acrylic or epoxy monomers, and a photochromic initiating system, will be optimized to produce materials with appropriate mechanical properties and self-healing character given by the dioxaborolanes connections. The resulting material will be analyzed through Dynamic Mechanical Analysis to determine the bond exchange kinetics, and the mechanical properties will be investigated through tensile and rheology tests.