Isothermal frontal polymerization: Miscibility studies to compare calculated solubility ratios of polymer seed to copolymer product of several polymer systems

CHED 711

Kristen N. Massey, massekn@millsaps.edu, Edgar R. Meyer, meyerer@millsaps.edu, John R. McPherson, mcphejr@millsaps.edu, and Lydia L. Lewis, lewisll@millsaps.edu. Department of Chemistry, Millsaps College, 1701 N. State St., Box 150894, Jackson, MS 39210
A directional polymerization known as isothermal frontal polymerization (IFP) can be used to produce gradient refractive index materials (GRINs). IFP occurs when a solution of liquid monomer and thermal initiator diffuse into a polymer seed (a small, hard piece of plastic) and create a viscous region where the speed of the liquid monomer solidification rapidly increases and travels as a wave through the system. IFP manufactures GRINs by incorporating a second monomer (monomer-2) into the original monomer solution where monomer-2 diffuses into the viscous region at a slower rate than monomer-1. The resulting product is a combination of seed-polymer and copolymer. Because the polymer seed is incorporated into the gradient material, phase separation pockets can occur for ratios of seed to copolymer that are outside the miscibility window calculated using solubility parameters. We present the experimental and theoretical results for these miscibility windows for several polymer systems.