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Polymer , 2004 , 45, 8377-8393.

2.4. 2.2. 2.0. 61.2  m. permeability (barrer). 1.8. 35.6  m. 8.50  m. 1.6. 3.60  m. 1.85  m. 2. O. 1.4. 0.99  m. 0.72  m. 1.2. 0.41  m. 1.0. 1. 10. 100. 1000. 10000. Aging time (hr).

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Polymer , 2004 , 45, 8377-8393.

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  1. 2.4 2.2 2.0 61.2 m permeability (barrer) 1.8 35.6 m 8.50 m 1.6 3.60 m 1.85 m 2 O 1.4 0.99 m 0.72 m 1.2 0.41 m 1.0 1 10 100 1000 10000 Aging time (hr) Permeation of Penetrants in Nanocomposites Donald R. Paul (University of Texas at Austin),DMR-0238979 Typical analyses of polymer composites assumes the matrix has the same properties as in the pure state; however, this may not be so when the size of the dispersed phase becomes very small since polymers at interfaces can have different properties than in bulk. Similarly, very thin polymer films (e.g., membranes) may have different properties than in the bulk state. We have found that thin films of glassy polymers undergo physical aging at rates that are orders of magnitude more rapid than seen in bulk. We have devised accurate techniques of studying this behavior which include monitoring gas permeation and optical properties (by ellipsometry) over long aging times. Thus, the properties of these thin films are very different than in the bulk state. Oxygen permeation in thin films of glassy polysulfone (a materials used to make high flux gas separation membranes) of various thicknesses as a function of time at 35oC. The rate of decline in permeability increases as the films become thinner. Heating aged films above Tg returns them to their original state.. Polymer, 2004, 45, 8377-8393.

  2. Permeation of Penetrants in NanocompositesDonald R. Paul (University of Texas at Austin),DMR-0238979 • Outreach • Each semester, we have 1-3 undergraduate students work, often for course credit, in our labs on polymer research. • Our group participates in the Welch Summer Scholar Program to expose high school students to science. • Each Spring UT-Austin holds an open house for the public called UT-Explore. Our group conducts a day-long series of fun demonstrations relating to polymers. Education This grant currently supports one graduate student pursuing a Ph.D., Ms. Ivy Huang who will finish soon and begin employment with Membrane Technology Research, Inc., and one post-doctoral fellow: Shuichi Takahashi. The pictures below show scenes from UT-Explore where our graduate students involve kids (and sometimes their parents!) in polymer experiments and demonstrations.

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