Šourková Hana, Špatenka Petr
Faculty of Mechanical Engineering, Department of Materials Engineering, Czech Technical University in Prague, Karlovo náměstí 13, 121 35 Prague 2, Czech Republic.
Polymers (Basel). 2020 Sep 15;12(9):2099. doi: 10.3390/polym12092099.
Polyethylene powder of average particle diameter of 160 µm was activated in a plasma reactor made from aluminum of volume 64 dm at the pressure 100 Pa. Dense oxygen plasma was sustained with a microwave discharge powered by a pulsed magnetron source of power 1 kW mounted onto the top flange of the plasma reactor. Polymer powder was treated in a batch mode with 0.25 kg/batch. The powder was placed into a stainless-steel dish mounted in the center of the reactor where diffusing plasma of low ion density, and the O-atom density of 2 × 10 m was sustained. The powder was stirred in the dish at the rate of 40 rpm. The evolution of powder wettability versus treatment time was measured using the Washburne method, and the surface composition was determined by X-ray Photoelectron Spectroscopy (XPS). The wettability versus the oxygen concentration assumed a parabolic behavior. The maximal oxygen concentration, as revealed by XPS, was 17.5 at.%, and the maximal increase of wettability was 220%. The efficiency of O-atoms utilization in these experimental conditions was about 10% taking into account the spherical geometry of dust particles and perfectly smooth surface. The method is scalable to large industrial systems.
平均粒径为160 µm的聚乙烯粉末在一个由体积为64 dm³的铝制成的等离子体反应器中，于100 Pa的压力下被激活。通过安装在等离子体反应器顶部法兰上的功率为1 kW的脉冲磁控管源产生的微波放电来维持致密的氧等离子体。聚合物粉末以0.25 kg/批次的批量模式进行处理。将粉末放入安装在反应器中心的不锈钢盘中，在那里维持低离子密度的扩散等离子体以及2×10¹² m⁻³的O原子密度。粉末在盘中以40 rpm的速率搅拌。使用沃什伯恩法测量粉末润湿性随处理时间的变化，并通过X射线光电子能谱（XPS）确定表面成分。润湿性与氧浓度呈现抛物线行为。XPS显示的最大氧浓度为17.5 at.%，润湿性的最大增加为220%。考虑到粉尘颗粒的球形几何形状和完美光滑的表面，在这些实验条件下O原子的利用效率约为10%。该方法可扩展到大型工业系统。
