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- Introduction of functional groups (2)
- Plasma modification (2)
- Reactions at polymer surfaces (2)
- Adhesion (1)
- Adhesion polypropylene-aluminium (1)
- Aerosol-assisted DBD (1)
- Aluminium (1)
- Analytik (1)
- Expanded Graphite (1)
- Functionalization (1)
- Gas Discharge Plasma (1)
- Humidity (1)
- LDPE (1)
- Plasma polymers (1)
- Plasmatechnologie (1)
- Polymer (1)
- Polypropylene (1)
- Spacer-bonded functional groups (1)
- Surface Chemistry (1)
- Tailored interface structures (1)
- UV weathering (1)
Introduction of irregularities into plasma polymers by radiative and auto-oxidative processes
(2005)
Reactions and Intermediates at the Metal-Polymer Interface - Detected by XPS and NEXAFS Spectroscopy
(1998)
Mixtures of hexamethyldisiloxane (HMDSO) and oxygen have been used for deposition of SiO2-like layers by plasma polymerization under low-pressure conditions onto polyethylene and polystyrene used as basecoat. Water glass was cast onto these 0.5 pm plasma thick siloxane-like layers with a thickness of 5 to 40 mu m. The adhesion of these bilayer systems and their flame resistance were tested. The effect of different plasma parameters such as monomer/gas ratio, pressure and power input into the discharge on the deposition rate and the composition of the formed layers was studied. Characterization and chemical composition of the formed films were performed using infrared, X-ray photoelectron and solid state nuclear magnetic resonance spectroscopy. Peel strengths of composites were measured and the locus of peel front propagation was detected. Thermal properties of composites were analyzed by thermo-gravimetric analysis. Finally, the fire-retardant properties of thick coated polymers were determined by exposure to flames and the behavior of coatings on the polymers during flaming was observed visually.
Different surface treatments of polypropylene (PP) were tested to improve the peel strength of aluminium-PP systems. Plasma exposure followed by chemical grafting of spacers with -SiOH endgroups and thin adhesion promoting layers deposited by aerosol-assisted DBD using aqu. solutions of classic polymers were compared. Both methods were effective, however, –SiOH terminated spacers effected no peeling also after ageing.
Photo-oxidative ageing of polymers under defined exposure (UV, humidity) was investigated from two points of view: a) the ageing process Starts from the topmost surface and penetrates slowly towards bulk and b) radicals play an important role among ageing. Therefore, X-ray photoelectron (XPS) and electron spin resonance (ESR) spectroscopy were applied to show both, the progressive incorporation of oxygen during in-situ UV irradiation (XPS) and the formation of radicals (ESR) in the polymer. The intensity of ESR Signals served as measure for radical concentration. The Validation of this correlation was checked for polyethylenes (PE) equipped with different concentrations of Hostavin N30 UV stabilizer.
The outdoor weathering of polymers is mainly due to UV radiation, water, Pollution, humidity, temperature etc. To understand the effects of weathering, simulated tests need to be undertaken in lab scale. Such tests must be quite efficient and similar to the effects of natural weathering. This paper mainly focuses on the effects of UV radiation along with humidity on LDPE.
Plasma processes are used in many fields of Science and technology. While a plasma oxygen treatment produces a broad variety of different oxygen-containing functional groups, tailored - surface functionalisation demands preset functional groups in known concentration. Due to the fact that most of plasma experiments need expensive vacuum equipment increased efforts are to observe to apply atmospheric pressure plasma processes. Thus, Dielectric Barrier Discharge (DBD) and corona treatment of polymer foils have a long tradilion in industry to modify them for printing, laminating, adhesion promotion, etc. Thercibre, increasing interest is observed to make these atmospheric pressure processes more effeclive. Newly developed methods like plasma-printing were used for surfaces in biological and medical applications or for printed circuits.