| Research Abstract |
For the utilization of high performance polymeric materials having high resistance, high modulus and high strength, two important steps of research are requested ; to know the flow and deformation behavior at high temperatures and to apply the results to polymer processing of the materials. The objects of this research project are to develop a new rheometer, to measure the rheological properties of high performance polymeric materials, which sometimes call the engineering plastics, and finally to find some relations between the performance of the end-products and processing conditions such as stress and/or strain histories applied on the materials.
During the term of this project (1988-1990), objectives of the research have been almost accomplished. First, a new rheometer was developed, which made it possible to measure the viscoelasticity of polymeric materials at high temperatures of 350-500. However, the problem on thermal degradation of materials is still in question. Secondly, viscoelastic and rheological properties under various types of deformations have been measured for many of engineering plastics, such as thermotropic liquid crystalline polymers, poly (ether ether ketons') poly (phenylene sulfides,) poly (ether ketons), and so on. Also the relation between the mechanical properties and the processing conditions was discussed and the results were directly utilized for the improvements in the film-forming process.
Studies on applicability of some current-developed constitutive equations, including the Leonov and Larson Models, to shear, elongational and biaxial flow-deformations have been made. The stress-strain relations under various types of deformations have been found and discussed in terms of the internal elastic deformation of materials induced by the flow.
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