TY - JOUR A1 - Schartel, Bernhard A1 - Kühn, Gerhard A1 - Mix, Renate A1 - Friedrich, Jörg Florian T1 - Surface Controlled Fire Retardancy of Polymers Using Plasma Polymerisation N2 - Communication: Fire retardant coatings are deposited on polyamide-66 using plasma polymerisation. Chemical composition and thickness of deposits are adjusted varying the plasma treatment based on hexamethydisiloxane mixed with oxygen. The fire retardancy performances are evaluated using a cone calorimeter. The correlation between fire retardancy and thickness as well as chemical composition is discussed. KW - Cone calorimeter KW - Flame retardance KW - Heat release KW - Plasma polymerization KW - Polyamides PY - 2002 U6 - https://doi.org/10.1002/1439-2054(20020901)287:9<579::AID-MAME579>3.0.CO;2-6 SN - 1438-7492 SN - 1439-2054 VL - 287 IS - 9 SP - 579 EP - 582 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-1537 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Jörg Florian A1 - Mix, Renate A1 - Kühn, Gerhard T1 - Functional groups bearing plasma homo and copolymer layers as adhesion promoters in metal-polymer composites N2 - Functional groups bearing monomers were pulsed plasma polymerised with a degree of retained functional groups of 55–91%. The following functional groups could be produced at a maximum of: 30 OH, 18 NH2, and 24 COOH per 100 C atoms. A plasma-initiated radical copolymerisation could also be realised using the functional group bearing monomers as a source of functionalities, olefins as ‘chain-extenders’ and dienes as ‘chemical cross-linkers’. The peel strengths of Al layers on such plasma polymers were correlated to the type and density of functional groups. KW - Functional groups KW - Adhesion promoters KW - Metal-polymer composites PY - 2003 U6 - https://doi.org/10.1016/S0257-8972(03)00350-5 SN - 0257-8972 VL - 174-175 SP - 811 EP - 815 PB - Elsevier Science CY - Lausanne AN - OPUS4-2703 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Jörg Florian A1 - Kühn, Gerhard A1 - Mix, Renate A1 - Fritz, Andreas A1 - Schönhals, Andreas T1 - Polymer surface modification with monofunctional groups of variable types and densities N2 - The retention of chemical structure and functional groups during pulsed plasma polymerization was used for producing adhesion-promoting plasma polymer layers with high concentrations of exclusively one kind of functional groups, such as OH, NH2, or COOH. The maximum content of functional groups was 31 OH using allyl alcohol, 18 NH2 using allylamine, or 24 COOH per 100 C atoms using acrylic acid. To vary the density of functional groups, chemical co-polymerization with ethylene as 'chain-extending' co-monomer, or butadiene as 'chemical crosslinker' was initiated in the pulsed plasma. The composition of these co-polymers was investigated by XPS and IR spectroscopy. The concentrations of functional groups were measured by derivatizing with fluorine-containing reagents and using XPS. A set of plasma parameters was found to be a good compromise between a high number of functional groups and complete insolubility in water, ethanol or THF,which is needed for further chemical processing. Here, these monotype-functionalized surfaces were used in metal-polymer systems as adhesion-promoting interlayers to examine the influence of type and density of functional groups on adhesion. As expected, COOH- and OH-group-terminated interlayers showed maximum peel strengths to evaporated aluminium layers. The adhesion increased linearly with the number of OH groups to a maximum at about 27 OH per 100 C atoms. Higher concentrations of OH groups did not increase the peel strength further. KW - Co-polymers KW - Adhesion-promoting interlayers KW - Metal-polymer systems PY - 2003 U6 - https://doi.org/10.1163/156856103322396695 SN - 0169-4243 SN - 1568-5616 VL - 17 IS - 12 SP - 1591 EP - 1617 PB - VNU Science Press CY - Utrecht AN - OPUS4-2704 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Jörg Florian A1 - Kühn, Gerhard A1 - Schulz, Ulrich A1 - Jansen, Kirsten A1 - Bertus, Angela A1 - Fischer, S. A1 - Möller, B. T1 - Characterization of fluorinated polyethylene surfaces N2 - Polyethylene foils, used as greenhouse foils stabilized with various types of sterically hindered amine light stabilizers (HALS), showed an extraordinary prolonged lifetime on exposure to natural or artificial weathering if a gas-phase fluorination under low-pressure conditions was applied. The fluorination was performed using F2/N2 mixtures and provided ca. 50 F/100 C (fluorination degree ap25%). The lifetimes of fluorinated PE foils on exposure to artificial or natural weathering were increased at least by a factor of 2-4 as measured in terms of tensile strength and elongation at break. KW - Gas phase fluorination of PE KW - Fluorination kinetics KW - Weathering PY - 2003 U6 - https://doi.org/10.1163/156856103322113832 SN - 0169-4243 SN - 1568-5616 VL - 17 IS - 8 SP - 1127 EP - 1143 PB - VNU Science Press CY - Utrecht AN - OPUS4-2707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kühn, Gerhard A1 - Retzko, Iris A1 - Lippitz, Andreas A1 - Unger, Wolfgang A1 - Friedrich, Jörg Florian T1 - Homofunctionalized polymer surfaces formed by selective plasma processes N2 - Several possibilities exist to produce a modified polymer surface with a high density of only one sort of functional group such as: (i) the plasma grafting of unfragmented monomer molecules and their polymerization forms OH, NH2, COOH groups, etc. in concentrations of approximately 25 groups per 100 C atoms; (ii) selective plasma bromination provides 10–25 CBr groups; (iii) the plasma oxidation of polymer surfaces in an O2 plasma followed by the chemical reduction of all O-containing groups to OH groups by diborane, vitride™ (Na complex) or LiAlH4 yields 9–14 OH groups per 100 carbon atoms; and (iv) the grafting of spacers with different endgroups onto OH or CBr groups produces 7–10 spacer molecules/100 C. This work was focused on the formation of thin plasma deposited polymer layers with a maximum of (homo)functional groups and with a minimum of chemical irregularities using the pulsed plasma technique. The monomers were allylalcohol, allylamine, acrylonitrile and acrylic acid. The further intent was to study the interactions of functional groups (OH, COOH, NH2) and deposited metals (Cr, Al, Ti). It was expected that more basic (NH2), weakly basic or neutral (OH) or more acidic (COOH) groups would show different interactions and chemical reactions with metal atoms. KW - Pulsed plasma polymerization KW - Functional groups KW - Long-term stability KW - Polymer-metal composites PY - 2001 U6 - https://doi.org/10.1016/S0257-8972(01)01056-8 SN - 0257-8972 VL - 142-144 SP - 494 EP - 500 PB - Elsevier Science CY - Lausanne AN - OPUS4-6971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Jörg Florian A1 - Retzko, Iris A1 - Kühn, Gerhard A1 - Unger, Wolfgang A1 - Lippitz, Andreas T1 - Plasma polymers with chemically defined structures in contact with metals N2 - The retention of chemical structure and functional groups during plasma polymerization was investigated. Usually plasma polymer layers, prepared by a continuous wave radio-frequency plasma, are often chemically irregular in their structure and composition. To minimize these irregularities low wattages and the pulsed plasma technique were applied to avoid fragmentations. The first goal was to produce plasma polymers comprising double or triple bonds as precursors for electrically conducting polymers. Acetylene, ethylene, butadiene and polystyrene were used as monomers and deposited as thin polymer films by pulsed plasmas of low wattages. Styrene polymerization was strongly enhanced in the dark phase (plasma off) of a pulsed r.f. plasma caused by the reactivity of the vinyl-type double bond. This could be confirmed by a verification of a rather high chemical regularity of the film sample. The oxygen content of this film measured by X-ray photoelectron spectrometry (XPS) was in situ 0% and after 24 h exposure to air lower than 1%. Additionally, post-plasma oxidations of trapped radicals with air could be suppressed using NO gas as radical quencher. Such quenched plasma polymer layers were completely stable against oxidation for a number of weeks. During the low-wattage pulse plasma polymerization metal atoms were simultaneously or layer by layer evaporated into the growing layer and in situ measured by XPS. These metal atoms are acting as dopants. Here, Li, K, Mg and Cr were used at different concentrations providing electrical conductivity and magnetic properties for the film. KW - Pulsed plasma KW - Plasma polymerization KW - Doping with metal atoms KW - Encapsulation of nanoparticles PY - 2001 U6 - https://doi.org/10.1016/S0257-8972(01)01051-9 SN - 0257-8972 VL - 142-144 SP - 460 EP - 467 PB - Elsevier Science CY - Lausanne AN - OPUS4-6972 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Jörg Florian A1 - Unger, Wolfgang A1 - Lippitz, Andreas A1 - Koprinarov, Ivaylo A1 - Kühn, Gerhard A1 - Weidner, Steffen A1 - Vogel, Lydia T1 - Chemical reactions at polymer surfaces interacting with a gas plasma or with metal atoms - their relevance to adhesion N2 - The chemical and morphological stabilities of polymer segments in the near-surface layer were investigated by spectroscopic methods such as X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy. Model studies were undertaken with Langmuir–Blodgett films, self-assembled monolayers and oligomer films. For thin polymer layers (30 to 500 nm), the changes in molecular-weight distributions of some polymers were investigated systematically by size exclusion chromatography, matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry and thermal-field flow fractionation for oxygen- and helium-plasma exposures. The polymer surfaces were found to be relatively stable at exposure to an oxygen low-pressure plasma up to ca. 2 s. This is important information to get maximum adhesion to metals in composites. In correlation to their redox potentials, potassium, aluminium and chromium react with oxygen functional groups at the polymer/metal interface. In a dedicated study, chromium was found to attack aromatic rings and form different reaction products. PY - 1999 U6 - https://doi.org/10.1016/S0257-8972(99)00229-7 SN - 0257-8972 VL - 116-119 SP - 772 EP - 782 PB - Elsevier Science CY - Lausanne AN - OPUS4-6981 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kühn, Gerhard A1 - Weidner, Steffen A1 - Decker, Renate A1 - Ghode, Archana A1 - Friedrich, Jörg Florian T1 - Selective surface functionalization of polyolefins by plasma treatment followed by chemical reduction N2 - Polymer surfaces can be finished with functional groups upon exposure to a plasma. Species of the plasma gas are attached at surface carbon atoms, forming functional groups of different composition. To produce a modified polymer surface with a high density and homogeneity of hydroxyl groups only, the oxygen-plasma-formed oxygen functional groups were chemically reduced by diborane and LiAlH4 with yields of 10 to 11 OH groups per 100 carbon atoms in the 3 to 5 nm near-surface layer as detected by X-ray photoelectron spectroscopy (XPS). The identification of hydroxyl groups was performed by means of attenuated total reflectance–Fourier transform infrared spectroscopy and XPS. KW - Attenuated total reflectance-Fourier transorm infrared spectroscopy KW - Chemical reduction of functional groups KW - Plasma modification KW - X-ray photoelectron spectroscopy PY - 1999 U6 - https://doi.org/10.1016/S0257-8972(99)00232-7 SN - 0257-8972 VL - 116-119 SP - 796 EP - 801 PB - Elsevier Science CY - Lausanne AN - OPUS4-6983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Kühn, Gerhard A1 - Friedrich, Jörg Florian T1 - Infrared-Matrix-assisted Laser Desorption/Ionization and Infrared-Laser Desorption/Ionization Investigations of Synthetic Polymers PY - 1998 SN - 0951-4198 SN - 1097-0231 VL - 12 SP - 1373 EP - 1381 PB - Wiley CY - Chichester AN - OPUS4-6988 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Kühn, Gerhard A1 - Decker, Renate A1 - Roessner, D. A1 - Friedrich, Jörg Florian T1 - Influence of Plasma Treatment on the Molar Mass of Poly(ethylene terephthalate) Investigated by Different Chromatographic and Spectroscopic Methods N2 - The influence of different types of low and atmospheric pressure plasma on poly(ethylene terephthalate) (PET) has been studied in terms of changes in molar mass and molar mass distribution. Apart from a variation of plasma gases (oxygen, helium) different types of plasma (microwave, radio frequency, corona discharge) were used for the plasma surface modification. The changes in molar mass and types of functional end groups of lower molar mass products were investigated by means of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOFMS), whereas the high-molar mass fraction was analyzed by means of size-exclusion chromatography (SEC). The formation of crosslinked products during exposure to a helium plasma, which emits preponderately energy-rich and intense ultraviolet radiation, was proved by means of thermal field-flow fractionation (ThFFF). This method combined with a multiangle laser light scattering (MALLS) detector allows detection of weakly crosslinked polymers and microgels. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1639-1648, 1998 KW - Poly(ethylene terephthalate) KW - PET KW - Plasma PY - 1998 UR - http://www3.interscience.wiley.com/cgi-bin/abstract/36482/ABSTRACT U6 - https://doi.org/10.1002/(SICI)1099-0518(19980730)36:10<1639::AID-POLA17>3.0.CO;2-H SN - 0360-6376 SN - 0887-624X VL - 36 IS - 10 SP - 1639 EP - 1648 PB - Wiley CY - Hoboken, NJ AN - OPUS4-6989 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -