Chemical modification of polyethylene surfaces in a nitrogen corona
Chemical modification of polyethylene surfaces in a nitrogen corona
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氮气电晕中聚乙烯表面的化学改性
DOI：
10.1002/pol.1976.130140410
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发表时间：
1976
期刊：
影响因子：
--
通讯作者：
D. Goring
中科院分区：
文献类型：
--
作者：
G. Courval;D. Gray;D. Goring
聚乙烯薄膜广泛用于包装用途，但通常需要对聚乙烯（PE）表面进行改性，以提高附着力或可印刷性(1)。已经表明(2)电晕放电处理聚乙烯导致其自粘和润湿显著增加。尽管这种表面改性的方法在工业上是常用的，但对该过程的机理仍然存在一些争议。虽然多次内反射红外光谱法(2)表明，在氧电晕下处理的PE片材表面形成羰基，但在氮电晕下处理后，表面没有发现化学修饰，尽管处理后的表面性能得到了类似的效果。然而，已经证明(4)，当将聚合物置于氨或氮氢等离子体中时，各种聚合物表面的胺基附着会发生。也有一些间接证据（5,6）表明，聚乙烯薄膜暴露于氮等离子体可能在聚合物表面形成氮化合物。因此，将聚乙烯暴露于含氮大气中的电晕放电可能会将含氮基团引入聚合物表面。本文利用电子能谱（ESCA）和染料吸附法研究了电晕处理对聚乙烯表面的化学效应。ESCA作为研究表面的一种方法现在已经很成熟(7)，这项技术最近被用来(8)证明在暴露于氮等离子体后，在醋酸纤维素膜表面形成含氮基团。事实上，如果氮与PE表面发生化学反应，就会形成碱性基团，在适当的条件下，这些基团应该能吸附水溶液中的酸性染料。
Polyethylene film is widely used for packaging purposes, but it is often necessary to modify the surface of the polyethylene (PE) to improve adhesion or printability (1). It has been shown (2) that corona discharge treatment of polyethylene leads to marked increases in its autohesion and wetting. In spite of the fact that this method of surface modification is commonly used industrially, there is still some controversy (3) over the mechanism of the process. Although it has been shown (2) by multiple internal-reflectance infrared spectrometry that carbonyl groups are formed on the surface of PE sheets treated in an oxygen corona, no chemical modification of the surface has been detected after treatment in a nitrogen corona, despite the similar effects obtained in the surface properties after such treatment. It has been shown (4), however, that the attachment of amine groups to the surface of various polymers occurs when the polymer is placed in an ammonia or a nitrogen and hydrogen plasma. There is also some indirect evidence (5, 6) that exposure of polyethylene film to a nitrogen plasma may form nitrogen compounds on the polymer surface. Thus, it seemed likely that exposure of PE to a corona discharge in a nitrogen atmosphere would introduce nitrogen containing groups onto the polymer surface. In the present work, the chemical effects of such corona treatment on polyethylene surfaces were sought with the aid of electron spectroscopy (ESCA) and a dye adsorption method. The use of ESCA as a method of studying surfaces is now well established (7), and this technique has recently been used (8) to demonstrate that nitrogen-containing groups are formed on the surface of cellulose acetate membranes after exposure to a nitrogen plasma. If nitrogen were, in fact, to react chemically with the PE surface, the formation of basic groups would be expected, and under appropriate conditions such groups should adsorb acidic dyes from aqueous solution.