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A study of the factors effecting layer thickness uniformity and layer breakup in microlayered coextruded films.

机译：对影响微层共挤薄膜层厚均匀性和层破裂的因素的研究。

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Microlayer coextrusion offers the opportunity to economically commercialize the production of nanometer thick film. A major obstacle towards commercialization is the non-uniform thickness of these layers and their breakup into droplets, which is also known as a scattering instability. Prior research had indicated a strong interaction between material properties and process parameters. Therefore, the focus of this research effort was to better understand and then identify the coextrusion parameters and material properties that governed the layer non-uniformity and scattering.; Initial studies had indicated that there existed an interaction between the two extruders, which gave rise to pressure fluctuations and non-uniform flow. The interaction of the two extruders was studied by analyzing the pressure signals at the two extruders and the junction of the two streams. A response surface method was used to analyze the two extruders individually, the number of layer multiplying elements and finally the interaction between the two extruders and the effect they had on pressure, surging, flow rate and torque. Although the interaction of the two extruders did result in higher backpressures, it did not decrease the output. The output was independent of the screw speed of the other extruder, however it did influence the melting mechanics along the screw. The more shear sensitive PMMA showed a greater degree of sensitivity than the Newtonian PC.; The influence of primary; coextrusion, and secondary; chill roll, processing on the final layer thickness was studied in a second set of experiments. For this purpose primary coextrusion process parameters such as screw speed ratio, die temperature and core melt temperature were changed and the effect on the layer thickness uniformity was studied. Similarly secondary process parameters such as nip gap and chill roll speed were also investigated. Thickness was measured using an Atomic Force Microscope (AFM). The screw speed ratio was the most important primary process variable in controlling the layer thickness. Chill roll velocity was an important process variable used to control layer thickness. These two process parameters also showed the greatest layer uniformity at screw speed ratios of unity and very high chill roll speeds.; Researchers have speculated that scattering is controlled by the same factors that governs droplet breakup in blend systems. The primary factors identified by them were the thickness of the layers, the interfacial tension and the number of layers. A 23 level full factorial DOE was carried out and the thickness of the samples measured using FMM. (Abstract shortened by UMI.)
机译：微层共挤出提供了将纳米厚膜生产经济化的机会。商业化的主要障碍是这些层的厚度不均匀以及它们分裂成液滴，这也称为散射不稳定性。先前的研究表明，材料性能和工艺参数之间存在很强的相互作用。因此，这项研究工作的重点是更好地理解并确定控制层不均匀性和散射的共挤出参数和材料性能。初步研究表明，两个挤出机之间存在相互作用，从而引起压力波动和流量不均匀。通过分析两个挤出机的压力信号以及两个料流的连接点，研究了两个挤出机的相互作用。使用响应面法分别分析两个挤出机，层倍增元件的数量，最后分析两个挤出机之间的相互作用以及它们对压力，喘振，流量和扭矩的影响。尽管两个挤出机的相互作用确实会导致较高的背压，但不会降低产量。输出量与另一台挤出机的螺杆速度无关，但确实会影响沿螺杆的熔化机理。对剪切更敏感的PMMA比牛顿PC表现出更高的灵敏度。小学的影响；共挤出和二次挤出；在第二组实验中研究了冷轧辊对最终层厚度的处理。为此目的，改变了主要的共挤出工艺参数，例如螺杆速比，模头温度和芯熔体温度，并研究了对层厚均匀性的影响。同样，还研究了辅助过程参数，例如辊隙和冷轧辊速度。使用原子力显微镜（AFM）测量厚度。螺杆速度比是控制层厚最重要的主要工艺变量。冷却辊速度是用于控制层厚度的重要过程变量。这两个工艺参数在统一的螺杆速度比和非常高的冷轧辊速度下也显示出最大的层均匀性。研究人员推测，散射是由控制混合系统中液滴破裂的相同因素控制的。他们确定的主要因素是层的厚度，界面张力和层数。进行了23级全因子DOE，并使用FMM测量了样品的厚度。 （摘要由UMI缩短。）

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