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Surface treatment of polyolefines by ambient-pressure discharges in N2-H2 mixtures - steps towards a new perspective

通过 N2-H2 混合物中的常压放电对聚烯烃进行表面处理 - 迈向新视角

基本信息

批准号：
171970336
负责人：
Professor Dr. Claus-Peter Klages
金额：
--
依托单位：
Institut für Oberflächentechnik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/171970336?language=en
关键词：
Surface treatment polyolefines ambient pressure

项目摘要

In the preceding DFG project (ATR-FTIR studies in situ of plasma-based amination of polymers using atmospheric-pressure barrier discharges) (Kl1096/19-1; 24 months) we demonstrated that the derivatization with aromatic aldehydes, hitherto commonly applied for quantification of primary amino groups -NH2 on plasma treated polymer surfaces, is by no means specific to amines but will also work with other functional groups such as imines >C=N-. Therefore the role of amino groups has probably been overestimated in the past, compared with alternative nitrogen-bearing functional groups. Applying FTIR-ATR in situ to the study of nitrogen-plasma treatment of polyethylene surfaces and the subsequent H/D isotope exchange or chemical derivatization with 4 trifluoromethyl-benzaldehyde we showed that a derivatization reaction with the aldehyde may take place although primary amines could not be detected with an independent method (exchange of N-H vs. N-D and IR spectroscopy of the region of expected ND2 deformation vibrations). These findings bear consequences for the applications of such surfaces as well as for the understanding of their chemical properties and formation mechanism.The purpose of the proposed project is to fathom these consequences, using physico-chemical investigations of the composition and reactivity of the nitrogen-plasma-treated surfaces. In order to test the hypothesis that the surface chemistry is dominated by imino groups, featuring both nucleophilic and electrophilic properties, rather than by amines, chemical gas-phase derivatization reaction with electrophilic and nucleophilic reagents will be studied in-situ using FTIR-ATR spectroscopy. Obtained spectra will be compared with those measured on suitable model compounds. In addition ex-situ measurements will be performed on plasma-treated polymer foils and wet-chemical reactions (reductions, hydrolyses) shall be included to obtain a comprehensive picture of these surfaces from a new perspective. The chemical studies will be complemented by physical measurements using NEXAFS, UPS and MIES jointly with research partners in Berlin and Clausthal, respectively; these methods offer additional possibilities to gain information with respect to the degree of unsaturation of chemical moieties on the surface ( CH=CH- vs. -CH2-CH2- and -CH=N- vs. -CH2-NH-).A question concerning the mechanism of plasma nitrogenation is the role of nitrogen atoms and hydrogen in the N2-H2 mixtures normally used. To this end FTIR-ATR studies in situ are planned during plasma treatment with varying H2 content between 0 and 4 %. These investigations shall be complemented by optical emission measurements aiming at a quantitative study of N atoms in the discharge afterglow. Based on these data it should be possible to assess if N atoms and excited N2 molecules formed therefrom may be responsible for the surface modification or if alternatively hydrogen-bearing species NHx have to be taken into consideration.

在之前的DFG项目中，（使用大气压阻挡放电对基于等离子体的聚合物胺化进行ATR-FTIR原位研究）（Kl1096/19-1; 24个月），我们证明了用芳香醛衍生化，迄今为止通常用于定量等离子体处理的聚合物表面上的伯氨基-NH 2，但也可与其它官能团如亚胺>C=N-起作用。因此，与其他含氮官能团相比，氨基的作用在过去可能被高估了。将FTIR-ATR原位应用于聚乙烯表面的氮等离子体处理和随后的H/D同位素交换或与4-三氟甲基-苯甲醛的化学衍生化的研究，我们表明，尽管伯胺不能用独立的方法检测到，但可能发生与醛的衍生化反应（N-H与N-D的交换和预期ND 2变形振动区域的IR光谱）。这些发现承担后果的应用程序，以及为了解其化学性质和形成mechanism.The拟议的项目的目的是要搞清楚这些后果，使用的组成和反应性的氮等离子体处理表面的物理化学调查。为了检验假设，表面化学是由亚氨基基团为主，具有亲核和亲电性能，而不是由胺，化学气相衍生化反应与亲电和亲核试剂将使用FTIR-ATR光谱原位研究。将获得的光谱与在合适的模型化合物上测量的光谱进行比较。此外，将对等离子体处理的聚合物箔进行非原位测量，并应包括湿化学反应（还原，水解），以从新的角度获得这些表面的全面照片。将分别与柏林和克劳斯塔尔的研究伙伴联合使用NEXAFS、UPS和MIES进行物理测量，以补充化学研究;这些方法提供了获得关于表面上化学部分的不饱和度的信息的额外可能性（CH=CH-对-CH 2-CH 2-和-CH=N-对-CH 2-NH-）。关于等离子体氮化机理的问题是氮原子和氢在通常使用的N2-H2混合物中的作用。为此，计划在等离子体处理期间进行原位FTIR-ATR研究，其中H2含量在0和4%之间变化。这些调查应辅以旨在定量研究放电余辉中N原子的光发射测量。基于这些数据，应该可以评估N原子和由其形成的受激N2分子是否可能是表面改性的原因，或者是否必须考虑含氢物质NHx。