Investigation of the Wettability Using Contact Angle Measurements of Green Polyethylene Flat Films and Expanded Vermiculite Clay Treated by Plasma

Polyethylene (PE) is a polymer that has a low adhesion property, which is related to its low surface energy. However, the plasma treatment aims the modification of the surface properties without affecting the polymer structure. In this sense, the objective of this work was to prepare biocomposite films via flat extrusion with Green PE matrix and Expanded Vermiculite Clay (VMT), contents of 1, 3 and 6%. The films were treated by plasma in two different ways: Oxygen (O2) atmosphere (Condition 1); and Argon/Hydrogen (Ar/H2) atmosphere followed by a plasma treatment under O2 atmosphere (Condition 2). The results of the contact angle measurements indicated that the incorporation of VMT and the conditions used for plasma treatment increased the films wettability due to the hydrophilic character of VMT and also as a consequence of the plasma. In contrast, the XRD diffractograms indicated that there were no significant changes in the films structure.

聚乙烯（Polyethylene, PE）是一类低粘附性聚合物，这一特性与其较低的表面能密切相关。等离子体处理的核心目标在于在不改变聚合物本体结构的前提下，对其表面性能进行改性。本研究以绿色聚乙烯（Green PE）为基体，添加质量分数分别为1%、3%和6%的膨胀蛭石黏土（Expanded Vermiculite Clay, VMT），通过平挤法制备生物复合薄膜。随后采用两种不同工艺对所得薄膜进行等离子体处理：其一为氧气（O₂）气氛处理（条件1）；其二为先经氩气/氢气（Ar/H₂）气氛处理，再于氧气气氛下开展二次等离子体处理（条件2）。接触角测量结果显示，得益于膨胀蛭石黏土的亲水特性以及等离子体处理的作用，VMT的掺入与所采用的等离子体工艺均提升了复合薄膜的润湿性。与之相对，X射线衍射（XRD）图谱分析表明，复合薄膜的本体结构未出现显著变化。