超临界CO2/PS微孔塑料挤出成型中成核数对气泡核自由长大的影响

以超临界CO2为发泡剂，研究了PS微孔塑料挤出成型中气泡核自由长大的机理，选用球形模型为表征气泡长大的物理模型，利用Dewitt本构方程、守恒定律和理想气体状态方程导出了气泡核自由长大阶段的数学模型。通过此数学模型着重对气泡成核数与气泡核自由长大平均半径之间的关系进行了数值模拟预测，并以实验验证了其正确性，结果表明：当其他加工条件不变时，增加气泡的成核数，气泡长大的平均半径将变小。因此，在制备微孔塑料时，我们可以通过增加气泡的成核数来改善制品的泡孔结构。

Influence of the Nucleation Density on the Bubbles Free Growth in Microcellular Plastics Extrusion Processing for Supercritical CO2/PS

Mechanism of the bubbles free growth was studied in PS microcellular plastics extrusion processing and supercritical carbon dioxide was used as foaming agent. The globe model was chosen as the physical model of the foaming system. The Dewitt constitutive equation and the equated law and the ideal gas law etc were used to establish the mathematical models of the bubbles free growth in the processing of microcellular plastics. The mathematical models were numerically evaluated for the influence of the nucleation density on the radius of the bubbles free growth, and were verified in correctness through experiment. The results showed the nucleation density increases when holding the else extruding condition invariability, lead to the bubbles growth radius reducing. So that we can improve bubble's morphology of the produces through increasing the nucleation density.