Computer Simulation of Structure Prediction for Polymer Blend and Alloy

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We considered based upon the previous research survey including our study that the dynamics simulation is effective for the prediction of structure development of fiber-filled and particle-filled polymer composite materials, polymer blends and polymer alloys and we can systematically deal with these predictions as a simulation technique.First we developed the prediction technique of three-dimensional behavior of fibers in a composite material by means of the dynamic particle simulation. We predicted the orientation, deformation and break of a single fiber in simple shear and elongation flow fields and the obtained results were found to be physically reasonable and be in agreement with some experimental results. Also we extended this technique to fiber-concentrated material by adding the fiber-fiber interaction. This simulation technique can be simplified and become easier for the distribution prediction of polymer blend because that only the particle trace is performed. It can be appli … More ed to the prediction of particle dispersion in particle-filled materials by adding the cohesive power, and to structure prediction in polymer alloys if we can make the successful model for the break up of liquid drop.Next we developed the prediction technique of polymer configuration using the spring-bead model by means of the molecular dynamics simulation and discussed the equivalence of the molecular model to the actual polymer. The simulation results varying the numbers of segments and chains showed that this model can represent the relaxation behavior of real polymer chain. However this model cannot appropriately represent the excluded volume effect when existence of several scores of monomers are assumed in a segment. The new model have to be discussed as several hundreds of monomers in a segment are required in order that the results by molecular dynamics are related to the continuum physical properties. We proposed the new model, "tube model", which can successfully show the extended volume effective and still have the merit of the spring-bead model.Last we developed the calculation method of optimized determination of material constants from experimental data of rheological properties for several constitutive equations and discussed the applicability of material models. It was found that several models can predict the material behavior in shear and elongation fields for weak-entangled polymer systems but multi values of non linear material constants in each relaxation mode and large number of relaxation modes were required for complicated systems. Less