TY - JOUR A1 - Weidner, Steffen A1 - Kühn, Gerhard A1 - Werthmann, Barbara A1 - Schröder, Hartmut A1 - Just, Ulrich A1 - Borowski, Renate A1 - Decker, Renate A1 - Schwarz, Bärbel A1 - Schmücking, I. A1 - Seifert, Ingetraut T1 - A new approach of characterizing the hydrolytic degradation of poly(ethylene terephthalate) by MALDI-MS N2 - The hydrolytic degradation of technical poly(ethylene terephthalate) (PET) was investigated by means of different methods such as size-exclusion chromatography (SEC), viscometry, light-scattering, thin-layer chromatography, end-group titration, and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The long-term degradation was simulated by exposing PET filament yarns to aqueous neutral conditions at 90°C for up to 18 weeks. By means of MALDI-MS and thin-layer chromatography, the formation of different oligomers was obtained during polymer degradation. As expected, an ester scission process was found generating acid terminated oligomers (H-[GT]m-OH) and T-[GT]m-OH and ethylene glycol terminated oligomers (H-[GT]m-G), where G is an ethylene glycol unit and T is a terephthalic acid unit. Additionally, the scission of the ester bonds during the chemical treatment led to a strong decrease in the number of cyclic oligomers ([GT]m). The occurrence of di-acid terminated species demonstrated a high degree of degradation. PY - 1997 U6 - https://doi.org/10.1002/(SICI)1099-0518(199708)35:11<2183::AID-POLA9>3.0.CO;2-Z SN - 0360-6376 SN - 0887-624X VL - 35 IS - 11 SP - 2183 EP - 2192 PB - Wiley CY - Hoboken, NJ AN - OPUS4-11357 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Mix, Renate A1 - Friedrich, Jörg Florian A1 - Kühn, Gerhard ED - Mutlu, M. T1 - Adhesion between metal atoms and polymer surfaces fitted with different types and variable density of functional groups T2 - 3rd workshop COST 527 CY - Antalya, Turkey DA - 2004-10-07 KW - Peel strength KW - Aluminium KW - Pulsed plasma KW - Allyl alcohol KW - Allylamine KW - Acrylic acid PY - 2005 SN - 975-491194-0 SP - 106 EP - 114 PB - Hacettepe Univ. Press CY - Ankara AN - OPUS4-11042 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 - Adhesion of metals to plasma-induced functional groups at polymer surfaces N2 - The peel strength of aluminium to polypropylene and poly(tetrafluoroethylene) was determined in dependence on the type and the concentration of functional groups on the polymer surface. For this purpose the polymer surface was equipped with monotype functional groups. The first method to produce monotype functionalized surfaces was an introduction of O functional groups using an oxygen plasma treatment and converting these groups to OH groups applying a wet chemical reduction. In result of this two-step treatment the hydroxyl group concentration at the polymer surface could be increased from 3–4 to 10–14 OH groups/100 C atoms. The second method consists in the deposition of a 150 nm adhesion-promoting layer of plasmapolymers or copolymers onto the polymer surface using the pulsed plasma technique. For that purpose functional groups carrying monomers as allyl alcohol, allylamine and acrylic acid were used. Applying the plasma-initiated copolymerization and using neutral “monomers” like ethylene or butadiene the concentration of the functional groups was varied. A correlation of peel strength with the ability of forming chemical interactions between Al atoms and functional groups was found: COOH > OH >> NH2 > H(CH2–CH2). KW - Peel strength KW - Aluminium KW - Polypropylene KW - Poly(tetrafluoroethylene) KW - Pulsed plasma KW - Allyl alcohol KW - Allylamine KW - Acrylic acid KW - Plasma surface treatment KW - Adhesion PY - 2005 SN - 0257-8972 VL - 200 IS - 1-4 SP - 565 EP - 568 PB - Elsevier Science CY - Lausanne AN - OPUS4-10897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Weidner, Steffen A1 - Kühn, Gerhard A1 - Roessner, D. A1 - Friedrich, Jörg Florian A1 - Unger, Wolfgang A1 - Lippitz, Andreas ED - Olefjord, I. ED - Nyborg, L. ED - Briggs, D. T1 - Changes in molecular weight distribution of polymers by plasma treatment T2 - 7th European Conference on Applications of Surface and Interface Analysis CY - Göteborg, Sweden DA - 1997-06-16 PY - 1997 SN - 0-471-97827-2 SP - 795 EP - 799 PB - Wiley CY - Chichester AN - OPUS4-6997 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 - Weidner, Steffen A1 - Kühn, Gerhard A1 - Just, Ulrich T1 - Characterization of oligomers in poly(ethylene terephthalate) by matrix-assisted laser desorption/ionization mass spectrometry PY - 1995 SN - 0951-4198 SN - 1097-0231 IS - 9 SP - 697 EP - 702 PB - Wiley CY - Chichester AN - OPUS4-11278 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kühn, Gerhard A1 - Weidner, Steffen A1 - Just, Ulrich A1 - Hohner, G. T1 - Characterization of technical waxes - Comparison of chromatographic techniques and matrix-assisted laser-desorption/ionization mass spectrometry N2 - Technical waxes and paraffins were investigated using supercritical fluid chromatography (SFC), matrix-assisted laser-desorption/ionization mass spectrometry (MALDI-MS) and size-exclusion chromatography (SEC). SEC enables the simultaneous determination of molecular masses up to high values and molecular mass distributions. The resolution of homologous species, however, is poor. In this respect the use of SFC is advantageous. Proper resolution of homologues may be provided up to Mr~1200 without great difficulty. To compare these chromatographic results MALDI-MS was applied for the determination of molecular masses and mass distributions in technical waxes for the first time. Using reflectron mode excellent MALDI mass spectra could be achieved in the molecular mass range up to 1000 Da. The mean values of the molecular masses calculated by MALDI-MS were in sufficient agreement with those of SFC. In the linear mode of MALDI-MS molecular masses could be determined to nearly 3000 Da. Beyond this mass range SEC still remains the method of choice. Advantages and difficulties of the used methods are discussed in this paper. PY - 1996 U6 - https://doi.org/10.1016/0021-9673(95)01255-9 SN - 0021-9673 VL - 732 IS - 1 SP - 111 EP - 117 PB - Elsevier CY - Amsterdam AN - OPUS4-11347 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 - CONF A1 - Friedrich, Jörg Florian A1 - Kühn, Gerhard A1 - Mix, Renate ED - Pershin, L. T1 - Chemical synthesis at plasma modified polymer surfaces T2 - 17th International Symposium on Plasma Chemistry (ISPC-17) CY - Toronto, Canada DA - 2005-12-07 PY - 2005 SP - 1(?) EP - 6(?) CY - Toronto AN - OPUS4-11944 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kühn, Gerhard A1 - Ghode, Archana A1 - Weidner, Steffen A1 - Retzko, Iris A1 - Unger, Wolfgang A1 - Friedrich, Jörg Florian ED - Mittal, K. L. T1 - Chemically well-defined surface functionalization of polyethylene and polypropylene by pulsed plasma modification followed by grafting of molecules T2 - 2nd International Symposium on Polymer Surface Modification: Relevance to Adhesion CY - Newark, NJ, USA DA - 1999-05-24 KW - Plasma modification KW - Chemical conversion of functional groups KW - Spacers KW - Polypropylene KW - Polyethylene PY - 2000 SN - 90-6764-327-0 VL - 2 SP - 45 EP - 64 PB - VSP CY - Utrecht AN - OPUS4-6975 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -