Influence of ethanol vapor addition on the surface modification of polyethylene in a dielectric barrier discharge
Influence of ethanol vapor addition on the surface modification of polyethylene in a dielectric barrier discharge
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DOI：
10.1016/j.apsusc.2017.05.111
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发表时间：
2017-10
影响因子：
6.7
通讯作者：
A. V. Deynse;R. Morent;C. Leys;N. Geyter
中科院分区：
文献类型：
--
作者：
A. V. Deynse;R. Morent;C. Leys;N. Geyter
本文在中压氩气、空气或氮气介质阻挡放电中添加高达50%的乙醇蒸汽，深入研究乙醇添加对低密度聚乙烯（LDPE）表面改性的影响。水接触角 (WCA) 和 X 射线光电子能谱 (XPS) 测量表明，乙醇蒸气对 LDPE 表面的添加效果取决于所使用的载气。与纯氩等离子体处理相比，在氩等离子体中添加乙醇对 LDPE 的润湿性和化学成分没有显着影响。然而，乙醇的添加确实略微增加了 LDPE 的表面粗糙度。在空气等离子体中添加少量乙醇蒸汽，可以在 LDPE 表面结合额外的氮和氧基团，从而使 WCA 值额外降低 11%。此外，由于乙醇蒸气的添加，LDPE表面粗糙度略有增加。然而，当使用氮气作为载气时，观察到添加乙醇的最显着效果。经过 N2/2% 乙醇等离子体处理后，与纯 N2 等离子体处理相比，WCA 值降低了 85%，达到 8.5°。这种非常亲水的 LDPE 表面是由于表面大量引入氧和氮基团而获得的，O/C 和 N/C 比率分别达到 32% 和 53%。 FTIR 测量还表明，观察到的 LDPE 极高的润湿性不是等离子体活化的结果，而是由于表面发生等离子体聚合效应，导致含有酮、酰胺以及 C 双键 N 基团的等离子体聚合物沉积。此外，还进行了老化研究，这些研究表明，对于所有载气，向放电气体中添加乙醇可显着抑制老化效应。因此，所有上述结论表明，基于乙醇蒸气的等离子体可以成为增加聚合物表面能的极好工具。
In this paper, ethanol vapor up to 50% is added to an argon, air or nitrogen dielectric barrier discharge at medium pressure to profoundly investigate the effect of ethanol addition on the surface modification of low density polyethylene (LDPE). Water contact angle (WCA) and X-ray photoelectron spectroscopy (XPS) measurements show that the ethanol vapor addition effect on the LDPE surface depends on the used carrier gas. Adding ethanol to an argon plasma has no significant effect on the wettability nor on the chemical composition of LDPE compared to a pure argon plasma treatment. Ethanol addition does however slightly increase the LDPE surface roughness. Addition of small amounts of ethanol vapor to an air plasma makes it possible to incorporate additional nitrogen and oxygen groups on the LDPE surface, resulting in an extra decrease of 11% in WCA value. Moreover, the LDPE surface roughness is slightly increased due to the ethanol vapor addition. The most significant effect of ethanol addition is however observed when nitrogen is used as carrier gas. After an N2/2% ethanol plasma treatment, an 85% reduction in WCA value to 8.5° is found compared to a pure N2plasma treatment. This very hydrophilic LDPE surface is obtained due to a significantly high incorporation of oxygen and nitrogen groups on the surface with an O/C and N/C ratio reaching 32% and 53% respectively. FTIR measurements also reveal that the observed extremely high wettability of LDPE is not the result of plasma activation but is due to plasma polymerization effects occurring on the surface resulting into the deposition of a plasma polymer containing ketones, amides as well as Cdouble bondN groups. In addition, ageing studies have also been conducted and these studies reveal that for all carrier gases, ethanol addition to the discharge gas significantly suppresses the ageing effect. All the above mentioned conclusions therefore indicate that ethanol vapor based plasmas can be an excellent tool to increase the surface energy of polymers.