Spatially-Directed Interfacial Polymerization

Abstract

Polymer-based materials and composites are widely used in applications from consumer goods to aircraft, due to their low cost and desirable properties. However, processing of both plastics and composites is often time consuming (taking hours or even days) and requires high temperatures, contributing to their energy footprint. This thesis introduces In Situ Interfacial Polymerization (ISIP) and Interfacial Photopolymerization (IPP), two room-temperature, interfacial polymerization (IP)-based methods for rapid manufacturing of polymers and their composites. First, In Situ Interfacial Polymerization (ISIP) is introduced as a fabrication technique for nanocomposites with tunable morphology. Using ISIP, dense carbon nanotube (CNT)-polymer composite sheets can be obtained in a matter of minutes by ISIP within a CNT network. Uniform aramid-CNT composite sheets obtained by this method show a two-fold increase in modulus and strength compared to pristine CNT sheets. Fundamental understanding of the balance between capillary flow and reaction-precipitation kinetics is implemented in a first principle macrokinetics model and enables expansion to porous materials beyond CNTs. Adjusting the transport-reaction balance through monomer selection, a new IP scheme based on aqueous diamines and organic dianhydrides is also introduced as a mean to produce nanotextured thermoformable polyetherimide films. While the ISIP technique facilitates composite formation within nanoporous materials, Interfacial Photopolymerization (IPP) enables photopolymerization printing of linear chain polymers without requiring a scaffold substrate. A prototype system is developed for IPP of poly(acrylonitrile) and the rate and resolution are quantified, showing the potential of IPP as a future photopolymerization 3D printing method for thermoplastics, contrasting current techniques that are restricted to non-recyclable thermoset polymers. A macrokinetics model of IPP is developed that balances diffusion/partition and polymerization reaction kinetics to assess build rate, enabling process optimization and material properties tunability.