Role of Polymer architecture and tacticity on mechanical and flow behavior (R.M. Kannan, Wayne State University, DMR )  Experiments: Rheo-FTIR spectroscopy, rheo-optics, X-ray, others  When branched density is high, polymers behave as soft-colloidal particles. In ‘miscible’ blends, the branched polymer may be ‘molecularly dispersed’, even at high weight fractions 1, acting as a well-dispersed nanoparticle filler.  In semi-syndiotactic polypropylenes, these is a deformation-induced, tacticity-dependent, structural transition, that makes these materials highly elastic 2 (3M collaboration)  Teaching: Collaborative research projects for minorities, Award-winning research projects for high school students, Case-study-based teaching, Chemical Engineering curriculum revision to reflect Nanotechnology, and Biotechnology. 1 Kharchenko SB, Kannan, RM, Macromolecules, 2003, 36(2), Sevegney M, et al. (Kannan RM), Macromolecules, 2003,36(17), 6472 Branched polymer in miscible blends

Supercritical CO 2 – based highly dispersed polymer nanocomposites (Kannan and Gulari) Nanocomposite Preparation: 1)Clay is exposed to scCO 2, followed by rapid depressurization. Expanded clay is then mixed with polymer. 2)The mixture from above is exposed to scCO 2, followed by rapid depressurization. Significant bulk density decrease is observed WAXD Rheology Conclusions: 1)scCO 2 process can effectively disperse modified and natural clays 2)Environmentally friendly process 3)Applicable to large number of industrially Important polymers 4)Rheo-optical FTIR spectroscopy is being utilized to understand the nanocomposite mechanical behavior Rheological improvements of more than 500%. Better dispersion compared to traditional methods (patents granted, company formed) scCO 2 process leads to better dispersion

Rheo-optical FTIR spectroscopy (Kannan) MichelsonInterferometer IR Source Plane Mirror Parabolic Mirror Low-Pass Filter Polarizer PEM Rheometer Detector Rapid, Quantitative, FTIR dichroism spectra acquisition over broad temperature rangeRapid, Quantitative, FTIR dichroism spectra acquisition over broad temperature range Individual component, and nanostructural orientations can be measured simultaneously in a multi-component blend Individual component, and nanostructural orientations can be measured simultaneously in a multi-component blend Applications to blends, nanocomposites, and metallocene polymersApplications to blends, nanocomposites, and metallocene polymers

Rheo-optical FTIR spectroscopy (Kannan) In summary, the complete optical train shows source IR light being subjected to three successive modulations before being partially absorbed by the sample, and then detected and converted to an electrical signal. Optical elements not mentioned previously: Mirrors: redirect and focus slightly diverging source beam. Sample rests on focus of parabolic mirror. UDR filter: filters out IR wavenumbers below 2000 cm-1; spectrometer uses undersampling mechanism to reduce spectral acquisition time.