We studied the characteristics of some thermoplastic elastomers (TPEs) using measurements of the temperature dispersion of the complex tensile modulus in the solid state, and the dynamic viscoelasticity and elongational viscosity in the molten state. The TPE samples included PVC/plasticizer-type TPEs and polymer alloy-type TPEs. The storage and loss shear moduli, G′ and G″, exhibited a power-law dependence on the angular frequency ω for most of the TPE samples measured. These findings indicate that these TPEs have long time relaxation mechanisms due to a self-similar fractal-like structure. The elongational viscosity behavior was different between the PVC/plasticizer-type TPEs and polymer alloy-type TPEs. The PVC/plasticizer-type TPEs exhibited strong strain hardening, while the other TPEs did not show any strain hardening. This difference is attributed to the morphology in these TPEs.

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In this paper, the influence of filler shape on foaming structures was investigated, using a batch method to penetrate supercritical fluid CO₂ into an ABS polymer matrix. ABS was mixed with several types of fillers, and processed by a hot press method. VGCF (vapor grown carbon fiber, diameter of 150nm), calcium carbonate (particle size of 1.8μm) and glass fiber (fiber diameter of 10μm) were used as fillers.
By adding VGCF, the average diameter of the foam cell decreased and the cell density increased compared with those in pure ABS resin. On the other hand, with the incorporation of calcium carbonate or glass fiber, the diameter increased and density decreased. In a sample with small fiber and particle diameters, the foam cell average diameter decreased and the cell density increased.

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