U.S.-Italy Cooperative Research: Rheology of Liquid Crystalline Polymers

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This U.S.-Italy award will support a research collaboration between Professor Donald G. Baird of the Virginia Polytechnic Institute and State University and Professor Giuseppe Marrucci of the University of Naples. The investigators plan to evaluate an existing molecular theory for describing the flow behavior of liquid crystalline polymers (LCP's) and to develop an alternative approach, if necessary. More specifically, the investigators plan to: (1) evaluate and test a theory first proposed by Doi, comparing theoretical predictions with experimental results for both lyotropic and thermo-tropic systems; (2) carry out simultaneous rheological experiments and structural measurements in order to develop relations between stress (deformation) and fluid structure; and (3) determine possible directions for developing constitutive theories reflecting the structure found in LCP's. There is considerable interest in the high aromatic polyestesters and polyamides that exhibit liquid crystalline order. High modulus fibers and films, and in some cases injection-molded parts, can be produced with these polymers. During the processing of these polymers, structure and orientation are generated during flow to a degree not found in flexible chain polymers. Consequently, in order to design processes for liquid crystalline polymers, it is necessary to establish the relation between stress and flow generated structure. By combining the experimental expertise of the U.S. side in understanding the rheology of LCP's with the theoretical strengths of the University of Naples group, the researchers should be able to provide deeper insights into the relation between deformation and structure for LCP's.