Untersuchungen zur Plasmaätzung von Polymeren. Teil I: Strukturänderungen von Polymeren nach Plasmaätzung

Friedrich, J.; Kühn, G.; Gähde, J.

doi:10.1002/actp.1979.010300802

Cited by 83 publications

(27 citation statements)

References 22 publications

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“…The peroxy radicals react with adjacent polymer chains forming hydroperoxides, which decay or rearrange to a broad variety of oxidation products. [16] The O/C ratios were plotted in dependence on time of exposure to the argon plasma as shown in Figure 2. The O-concentration in PE and PP increases with exposure time and then levels off after 1-min exposure at 19 and 24% O/C, respectively.…”

Section: Argon Plasma Treatment Of Polyolefinsmentioning

confidence: 99%

Effect of Br gassing after Ar plasma treatment of polyolefins

Ramanujam

Mix

Wagner

et al. 2013

Journal of Adhesion Science and Technology

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For simulation and acceleration of artificial polymer ageing, polyolefin foils were exposed to low-pressure Ar plasma. Plasma particle bombardment and irradiation induce C-C and C-H bond scissions by σ → σ ⁄ excitations on the surface and in near-surface layers. Consequently, radicals are generated. They react by recombination, cross-linking, metastable trapping of the radical site or formation of olefinic double bonds. The long-living and metastable trapped C-radicals as well as double bonds in polyolefins were immediately exposed to bromine vapour without breaking the vacuum after switching-off the plasma. These reactive sites rapidly react with the molecular bromine under formation of C-Br bonds. For 5 min of argon plasma exposure, the elemental concentration of bromine was 13% for polyethylene and 22% Br/C for polypropylene as analysed by X-ray photoelectron spectroscopy. Nevertheless, not all C radical sites have reacted with bromine. Later on, when the polyolefins brought in contact with ambient air, an additional post-plasma reaction of the remaining trapped radicals with oxygen was observed. The oxygen concentrations were lower after bromine gassing, thus repressing partially the post-plasma oxidation in the analysed layer (ca. 6 nm) by radical quenching. Such bromination took place either at the surface or in near-surface layers because the Attenuated Total Reflectance (ATR)-FTIR spectra (sampling depth ca. 2500 nm) did not show significant changes for argon plasma-treated PE foils with and without bromine vapour exposure. Further addition of bromine may also occur on C=C double bonds.Keywords: ageing of polyolefins; argon plasma; radical formation; formation of double bonds 1. Introduction Low-temperature plasmas have a wide range of applications like plasma polymerization, surface modification, microbial inactivation, etc. They contain many reactive species such as excited electrons, atoms, ions, etc. Such plasma is well suited to modify chemically inert polyolefin surfaces. The UV irradiation with wavelength shorter than 200 nm can attack the covalent bonds in the polymer. In the case of argon plasma, absorption lines occur at wavelengths of 105 and 107 nm for singly ionized argon and 92 and 93 nm for doubly ionized argon corresponding to energies of 12 and 15 eV.[1] These energies exceed considerably the dissociation energies of all covalent bonds in polyolefins.[2] The scissions of CÀC ($3.5 eV) and CÀH (3.5-4.0 eV) bonds in polyolefins by σ → σ ⁄ transitions are induced by such plasma vacuum UV radiation. Due to the semi-crystalline nature and the stretch-induced orientation of polyolefin foils, the radicals can be formed preferably in the amorphous regions or at the

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Section: Argon Plasma Treatment Of Polyolefinsmentioning

confidence: 99%

Effect of Br gassing after Ar plasma treatment of polyolefins

Ramanujam

Mix

Wagner

et al. 2013

Journal of Adhesion Science and Technology

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“…and finally, C-O-OH → decay, rearrangement, degradation products [50]. A concurrent mechanism may be the direct attachment of hydroperoxy radicals onto radical sites at the polyolefin surface according to:…”

Section: Role Of Hydroperoxy (-O-oh) Speciesmentioning

confidence: 99%

Role of Hydrogen Peroxide in Selective OH Group Functionalization of Polypropylene Surfaces using Underwater Capillary Discharge

Joshi

Friedrich

Wagner

2011

Journal of Adhesion Science and Technology

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Plasma chemical methods are well suited for introducing functional groups to the surfaces of chemically inert polymers such as polyolefins. However, a broad variety of functional groups are often formed. Unfortunately, for further chemical processing such as grafting of molecules for advanced applications a highly dense monotype functionalized polyolefin surface is needed. Therefore, the main task was to develop a selective surface functionalization process, which formed preferably only a single type of functional groups at the surface in high concentration. Amongst the novel plasma methods, the underwater plasma process (UWP) is one of most attractive options to solve the problem of monotype functionalization. Such plasma is an efficient source of ions, electrons, UV-radiation, high-frequency shock waves, radicals such as hydroxyl radical, and reactive neutral molecules such as hydrogen peroxide.In contrast to established gas phase glow discharge processes, the water phase limits the particle and radiation energies and thus the energy input into the polymer. By virtue of the liquid water environment, which moderates highly energetic plasma species, extensive oxidation, degradation, cross-linking and radical formation on the polymer are more limited as compared to gas plasma exposure. The variety of plasma produced species in the water phase is also much smaller because of the limited reaction possibilities of the plasma with water. The possibility to admix a broad variety of chemical additives makes underwater plasma even more attractive.Hydrogen peroxide and the catalyst (Fe-ZSM5) should influence and increase the equilibrium concentration of OH radicals in the underwater plasma process. It was found that these radicals played a very important role in OH functionalization of polyolefin surfaces. Hydrogen peroxide was identified to be the most prominent precursor for OH group formation in the UWP. The catalyst would affect the steady state of OH radical formation and its reaction with the substrate surface and thus accelerates the functionalization process.

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“…Zur Ermittlung des Einflusses der beschriebenen chemischen und strukturellen Veranderungen a n der Polymeroberflache (Oberflachen-, Tiefeneffekt) [3] Bei der nagchemischen, reduktiven Verkupferung ist eine vorangehende Wechselwirkung zwischen Radikalen (Peroxid-) oder Doppelbindungen usw. der aktivierten Probe mit der Zinn( 11)-chloridlosung und den anderen Badlosungen zu erwarten.…”

Section: Plasmachemische Modifizierung Der Polymeroberflacheunclassified

Untersuchungen zur Plasmaäzung von Polymeren. Teil III. Plasmamodifizierung von Polymeroberflächen zur Verbesserung der Hafteigenschaften der Polymere

Friedrich

Wittrich

Gähde³

1980

Acta Polymerica

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die Oberflachenmodifizierung als auch die Vernickelung uber Nickeltetracarbonyl im Plasma fuhrten jeweils zu ausgezeichneten Haftfestigkeitswerten zwischen Polymer und Kupferdeckschichten. Oberflachenaufrauhung, chemische und strukturelle Anderungen des Polymergefuges an der Oberflache und die Schaffung atzgasspezifischer funktioneller Oberflachengruppen werden als Ursache der Verbessernng der Hafteigenschaften angesehen. Ilccaeaoeanm R naaamennofiy mpaeaenum noauaepos. rIacmb I I I . ilioau@uuyupoeanue e naame noeepxnocmu noauaepoe c yeaam yayrtuenua ux aazeauu

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Untersuchungen zur Plasmaätzung von Polymeren. Teil I: Strukturänderungen von Polymeren nach Plasmaätzung

Cited by 83 publications

References 22 publications

Effect of Br gassing after Ar plasma treatment of polyolefins

Effect of Br gassing after Ar plasma treatment of polyolefins

Role of Hydrogen Peroxide in Selective OH Group Functionalization of Polypropylene Surfaces using Underwater Capillary Discharge

Untersuchungen zur Plasmaäzung von Polymeren. Teil III. Plasmamodifizierung von Polymeroberflächen zur Verbesserung der Hafteigenschaften der Polymere

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