マイクロセルラー技術は非活性な超臨界ガスを使用し,衝撃強度や靭性のような機械的物性の向上や流動性向上など,多くの利点を生み出す発泡成形技術で,最近注目されている.現在マイクロセルラープラスチックを産業用途に応用するため,押出成形と射出成形に適用する研究が進められている.本論文では,L/tを調節できる金型を設計し,L/tを変化させてサンプルの発泡倍率とその時の質量を測定した.本実験から約30μmの均一な発泡径を有する微細発泡が得られ,L/t=20の場合には約30.1%の発泡倍率が得られた.L/tと発泡倍率データはマイクロセルラー発泡用金型システムを設計する際の有効な手段になる期待される.

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Recently, the development of high-performance thermoplastic polymer composites has been a focus for the polymer engineering field. These polymer composites are formulated with polymer blends and alloys and various fillers. Twin-screw extruders can provide excellent mixing for these composites. The filler dispersion depends on processing conditions such as processing temperature, residence time, screw speed and screw profile. The physical properties of these polymer composites are also strongly dominated by the dispersion conditions of the filler.
In this study, conductive carbon-nanotube (CCNT) was used as a filler and polycarbonate (PC) as the matrix polymer. The conductivity of these composites was measured and related to the dispersion of CCNT under different processing conditions. The dispersion was characterized by the dispersion ratio. The total shear strain [γ·t], the product of shear rate [γ] and residence time distribution [t], was used as a dispersion parameter.
We can conclude that the filler dispersion depends on the processing parameters of the twin screw extruder. Moreover the filler dispersion can be related to the total shear strain [γ·t] which is one of the dispersion parameters. An optimized condition for conductivity in these carbon-nanotube (CCNT) filled polymer composites can be determined by this correlation.

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