Many researches are being conducted on conductive plastic for use for static electricity prevention and electromagnetic shielding. The aim of this study is to fabricate a power circuit which allows flow of current to a considerable extent using compression molded conductive plastic. First, to minimize the electric resistance of the conductive plastic, experimentations were carried out on the volume resistivity and formability of a compression molded product containing a high amount of short copper fibers in the resin (16∼50vol%).
The results showed that 2.2×10^-5Ω·cm volume resistivity can be achieved. In the experiment, the composition was adjusted using commercially available conductive materials. We also studied the heat generation characteristics by passing about 10 ampere current through the compression molded material.

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This paper describes a new decoupled finite element method, which has been developed based on previous work and applied successfully to the high Weissenberg number problem of die-swell flow simulation using a single relaxation mode Giesekus model. The method is a modified version of the 2×2-subelement/non-consistent streamline upwind (2×2SU) scheme. To improve the convergence behavior, several additional techniques are incorporated: (1) unification of the number of Gaussian points to evaluate integrations with same accuracy for momentum equation and for constitutive equation, (2) as for discritization of momentum equation with the rearranged form substitution and for getting diagonal dominant matrices, treatment of velocity (v) as known and treatment of velocity gradient (∇_v) (and its transpose) as unknown, both of which appear in the definition of upper convected derivative of the elastic part of extra-stress tensor (E^∇), and (3) stepwise reduction of the relaxation factors for velocity-stress fields and for free surface shape, respectively. The new method enables us to predict die-swell flow simulations at Weissenberg numbers over 400.

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A simulation method, which predicts the viscoelastic properties of polydisperse polymer melts from a relaxation spectrum, is applied to blend systems. From theoretical considerations of the molecular weight distribution curve, the molecular weight distribution curve of blends can be treated as a polydisperse polymer melt. From this knowledge, weight averaged molecular weight and polydispersity were calculated, the relaxation spectrum was predicted and the viscoelastic properties were calculated from this relaxation spectrum. Good agreement was found between measured and predicted viscoelastic properties in a wide frequency region.

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[in Japanese]

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