Melt Blown Cross-linked Fibers from Thermally Reversible Diels-Alder Polymer Networks*

Melt blowing is a process in which liquid polymer is extruded through orifices and then drawn by hot air jets to produce nonwoven fibers. Melt blown nonwovens constitute more than 10% of the $50 billion global nonwovens market. Thermoplastic feedstock, such as polyethylene, polypropylene, and poly(butylene terephthalate), have dominated melt blown nonwovens because of their combined cost, good chemical resistance and high-temperature performance. Cross-linked nonwovens from other commodity polymers (e.g., (meth)acrylates, styrenics, silicones, etc.) could be attractive alternatives; however, no commercial cross-linked nonwovens currently exist. Here, cross-linked fibers were produced via one-step melt blowing of thermoreversible Diels-Alder polymer networks comprised of furan- and maleimide-functional methacrylate-based polymer backbones. These dynamic networks decross-link and flow like viscous liquids under melt blowing conditions, then revert to a network via cooling-induced cross-linking during/after melt blowing. Finally, the resulting cross-linked fibers can be recycled because of their reversible dynamic nature, which may help address the microfiber pollution problem.