Controlling Fiber Morphologies Arising from Room-Temperature Cure Blowing

Cure blowing is a fiber manufacturing process whereby simultaneous extrusion and photopolymerization of a liquid monomer mixture produces nonwoven fibers of cross-linked polymers at room temperature with little or no solvent. Using a lab-scale die resembling that used in commercial melt blowing processes, we demonstrate the dependence of final cure blown fiber morphology on a competitive interplay of three categories of parameters corresponding to the photopolymerization kinetics, monomer mixture fluid properties, and process operating conditions, by quantifying and comparing the respective characteristic timescales for vitrification, fluid relaxation, and fiber flight. By constructing timescale-dependent morphology maps for two chemically distinct model systems, these timescales are found to account for the observed fiber morphology transitions irrespective of the photopolymerization mechanism. These morphology maps furnish a predictive tool for implementing different photopolymerization chemistries to achieve cure blown fibers with prescribed morphologies and properties for a wide array of applications.