以層倍增技術共擠製高分子多層膜的特性之探討

Abstract

單一性質的高分子薄膜已無法應付日益增加的功能需求，多層化高分子薄膜現今已大量運用於包裝、光學等用途，然目前應用之多層化高分子薄膜，大多使用的是層數較少且層厚較厚的薄膜，微/奈米層厚之高分子多層膜已經成為了技術發展的新方向。 本研究的目的是要利用層倍增技術共擠製高分子多層膜，並探討製程中影響層厚與層厚均勻性之因素及其層間界面的觀察。 研究中使用自行設計之層倍增模具，搭配上實驗室先前架設之共擠製設備，將原為兩層之高分子材料以二的倍數反覆交疊逐漸增加層數並減低層厚，並以不同材料、不同擠出速度與不同擠出速度比作為實驗參數，探討這些參數對多層膜層厚與層厚均勻性的影響。實驗製得的多層膜將利用掃描式電子顯微鏡(SEM)和光學顯微鏡(OM)進行層厚與層間界面的觀察。 研究結果顯示，試片因流道出口面上的速度差異導致試片左右兩側發生扭轉。PP/PA擠製時為增加層間結合性採用共混機制因而導致共混層產生球形的結構並破壞了層厚的均勻性，但在較低的擠製速度時球形結構可以有效的減少。另外PMMA/PC擠製時層間疊合效果良好。較慢的擠出速度會使層厚的均勻性較佳。PMMA/PC兩者之間的擠出速度差異越大，越難控制層厚比。本研究結果可供未來探討多層膜性質時，層厚尺寸與層厚均勻性對其影響之參考。

Multi-layered polymer films have been widely used in packaging and optical components, since unitary characteristic of the polymer film can’t satisfy the requirements of increasing function. Most current applications of multi-layered polymer films use few layer numbers and thick layer thickness films. Multi-layered polymer film layer thickness in micrometer and nanometer scale has become a new trend of technological development. This study use the layer-multiplying technology to coextruded multi-layer polymer films and observes the manufacturing processes that affect layer thickness, the uniformity of layer thickness, and the interfaces between layers. This research combines a new mold design with a co-extrusion system which developed previously. The mold enables repeated overlap of two polymer layers to reduce layer thickness and increase layer number. Layer thickness and layer thickness uniformity are also compared in different materials, extrusion speeds, and extrusion speed ratios. Specimen are then compared by optical microscope and scanning electron microscope. Experimental results show that twisting on the left and right sides of the specimen results from different flow rates. Polymer blend is used to increase the interlayer binding in PP/PA multi-layered films, but the process destroys the layer thickness uniformity by forming spherical structures. However, a low extrusion speed can reduce the formation of spherical structures. In contrast, PMMA/PC films have good layer combinations. Low extrusion speed improve the thickness uniformity of PMMA/PC film. When the difference in extrusion speeds between PMMA and PC increases, the thickness ratio becomes difficult to control. This study of the effects of layer thickness and layer thickness uniformity provide a useful reference when investigating multi-layer polymer film properties.