Laser line deflection to study the diffusion of neat methyl methacrylate and high molecular-weight poly(methyl methacrylate)

CHED 712

John R. McPherson, mcphejr@millsaps.edu1, Kristen N. Massey, massekn@millsaps.edu1, Edgar R. Meyer, meyerer@millsaps.edu1, Joshua S. Hanna, hannajs82@yahoo.com2, and Lydia L. Lewis, lewisll@millsaps.edu1. (1) Department of Chemistry, Millsaps College, 1701 N. State St., Jackson, MS 39210, (2) School of Polymer Science and High Performance Materials, The University of Southern Mississippi, 118 College Drive #10076, Hattiesburg, MS 39406
Isothermal Frontal Polymerization (IFP) is a self-sustaining, directional polymerization used to produce gradient refractive index materials (GRINs). Mathematical models of IFP have been constructed in hopes of producing improved GRINs. One drawback to these models is the lack of information in the literature on the diffusion processes that occur in IFP. We modified laser line deflection (or Weiner's method) to detect distinct boundaries between the pure solvent and swollen layer and between the swollen layer and pure polymer. LLD showed that a finite slab of high-molecular weight PMMA exhibited two distinct regions of swollen polymer, which affected how the mean mutual diffusion coefficient was calculated. Using the experimental parameter of solvent penetration velocity, we calculated the mean mutual diffusion coefficient to be on the order of E-6 cm2/s. In addition, we determined its temperature independence within the standard deviation of the measurements.
 

Undergraduate Research Poster Session: Polymer Chemistry
11:00 AM-1:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Poster

Division of Chemical Education

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008