TY - CONF A1 - Weidner, Steffen A1 - Lauer, F. A1 - Seifert, S. A1 - Diehn, S. A1 - Kneipp, Janina T1 - MALDI-TOF MS und MALDI-MSI zur Identifikation und Klassifizierung von Pollen N2 - Es werden die letzten Ergebnisse präsentiert, die es ermöglichen, einzelne Pollenkörner unterschiedlicher Arten in Mischungen mittels MALDI-TOF Massenspektrometrie bzw. MALDI-TOF Imaging zu messen und unter Zuhilfenahme multivariater Auswertemethoden zu klassifizieren. T2 - 24. Bruker MALDI Anwendertreffen CY - Leipzig, Germany DA - 18.02.2019 KW - MALDI-TOF Massenspektrometrie KW - Pollenkörner KW - Klassifizierung KW - MALDI Imaging KW - Multivariate Analyse PY - 2019 AN - OPUS4-47441 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Scheliga, F. T1 - Synthesis of cyclic poly(l-lactide) catalyzed by Bismuth salicylates-A combination of two drugs N2 - l‐lactide was polymerized in bulk at 160 or 180°C with mixtures of bismuth subsalicylate (BiSub) and salicylic (SA) as catalysts. The SA/Bi ratio and the monomer/Bi ratio were varied. The highest molecular weights (weight average, Mw) were achieved at a SA/Bi ratio of 1/1 (Mw up to 92 000 g mol−1). l‐Lactide was also polymerized with combinations of BiSub and silylated SA, and Mw values up to 120 000 g mol−1 were achieved at 180°C. MALDI‐TOF mass spectrometry and Mark‐Houwink‐Sakurada measurements proved that under optimized reaction conditions the resulting polylactides consist of cycles. KW - Polylactide KW - MALDI-TOF MS KW - Cyclization KW - Catalyst KW - Salicylate PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488622 DO - https://doi.org/10.1002/pola.29473 SN - 0887-624X SN - 1099-0518 SP - 29473 PB - Wiley AN - OPUS4-48862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Jörg Florian A1 - Unger, Wolfgang A1 - Lippitz, Andreas A1 - Koprinarov, Ivaylo A1 - Weidner, Steffen A1 - Kühn, Gerhard ED - Nowack, H. T1 - Wechselwirkungen zwischen plasmamodifizierten Polymeroberflächen und Metallen T2 - 5. Internationale Fachtagung - ND-Plasma-Technologie CY - Duisburg, Deutschland DA - 1997-09-22 PY - 1997 VL - 5 SP - 1(?) EP - 17(?) PB - Print-Service CY - Mülheim AN - OPUS4-6995 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Jörg Florian A1 - Unger, Wolfgang A1 - Lippitz, Andreas A1 - Geng, Sh. A1 - Koprinarov, Ivaylo A1 - Kühn, Gerhard A1 - Weidner, Steffen T1 - Modelling plasma-induced reactions on polymer surfaces using aliphatic self-assembling and LB layers PY - 1998 SN - 0257-8972 VL - 98 SP - 1132 EP - 1141 PB - Elsevier Science CY - Lausanne AN - OPUS4-6999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Friedrich, Jörg Florian A1 - Kühn, Gerhard A1 - Mix, Renate A1 - Retzko, Iris A1 - Gerstung, Vanessa A1 - Weidner, Steffen A1 - Schulze, Rolf-Dieter A1 - Unger, Wolfgang ED - Mittal, K. L. T1 - Plasma polymer adhesion promoters for metal-polymer systems T2 - 2nd International Symposium on Polyimides and Other High Temperature Polymers: Synthesis, Characterization and Applications CY - Newark, NJ, USA DA - 2001-12-03 KW - r.f. pulsed plasma KW - Plasma polymers with functional groups KW - Copolymers KW - Adhesion promoting interlayers KW - Metal-polymer systems PY - 2003 SN - 90-6764-378-5 VL - 2 SP - 359 EP - 388 PB - VSP CY - Utrecht AN - OPUS4-6967 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 - Weidner, Steffen A1 - Kühn, Gerhard A1 - Friedrich, Jörg Florian A1 - Unger, Wolfgang A1 - Lippitz, Andreas T1 - Plasmaoxidative Degradation of Polymers Studied by Matrix-assisted Laser Desorption/Ionization Mass Spectrometry PY - 1996 SN - 0951-4198 SN - 1097-0231 VL - 10 SP - 727 EP - 732 PB - Wiley CY - Chichester AN - OPUS4-7004 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 - TY - CONF A1 - Friedrich, Jörg Florian A1 - Unger, Wolfgang A1 - Lippitz, Andreas A1 - Koprinarov, Ivaylo A1 - Weidner, Steffen A1 - Kühn, Gerhard ED - Schindel-Bidinelli, E. T1 - Umweltfreundliches Metallisieren von Kunststoffen durch Plasmavorbehandlung in einem geschlossenen Reaktor T2 - Swissbonding 97 ; 11. Internationales Symposium Klebtechnik und Umwelt ; 11th International Symposium Bonding and Sealing Technology CY - Rapperswil, Schweiz DA - 1997-05-26 PY - 1997 SP - 1(?) EP - 3(?) PB - SWIBOTECH CY - Rorbas AN - OPUS4-6994 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Jörg Florian A1 - Unger, Wolfgang A1 - Lippitz, Andreas A1 - Weidner, Steffen A1 - Geng, Sh. A1 - Wigant, L. A1 - Wöll, Ch. A1 - Erdmann, J. A1 - Gorsler, H.-V. T1 - Characterization of plasma-modified organic surfaces by electron spectroscopy, SEIRA, and MALDI-TOF-MS T2 - 6th European Conference on Applications of Surface and Interface Analysis CY - Montreux, Switzerland DA - 1995-10-09 PY - 1995 SP - TC 11 PB - Wiley CY - Chichester AN - OPUS4-7001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Jörg Florian A1 - Wigant, L. A1 - Unger, Wolfgang A1 - Lippitz, Andreas A1 - Weidner, Steffen A1 - Kühn, Gerhard A1 - Geng, Sh. A1 - Erdmann, J. A1 - Gorsler, H.-V. T1 - Plasmavorbehandlungen von Polymeroberflächen T2 - 2. Freiberger Polymertag CY - Freiberg DA - 1995-05-30 PY - 1995 SP - 17 Seiten CY - Freiberg AN - OPUS4-7014 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. A1 - Weidner, Steffen T1 - SnOct 2-Catalyzed Syntheses of Cyclic Poly (l-lactide) s with Catechol as Low-Toxic Co-catalyst N2 - Polymerizations of l-lactide in bulk at 160 or 180 °C were performed with 1/1 mixtures of catechol (CA) or 4-tert-butylcatechol (BuCA) and tin(II)-2-ethylhexanoate (SnOct2) as catalysts and a variation of the Lac/Cat ratio. Weight average molar masses (Mw) up to 170,000 g mol−1 were obtained with CA and up to 120,000 g mol−1 with BuCA. The cyclic structure of the resulting poly(l-lactide)s was proven by MALDI-TOF mass spectrometry and by comparison of their hydrodynamic volumes with those of commercial linear poly(l-lactide)s. The predominance of even-numbered cycles increased with lower temperatures and shorter polymerization times. This fnding indicates that the cyclic architecture is the results of a ring-expansion polymerization mechanism. Addition of silylated BuCA as co-catalyst was less favorable than addition of free BuCA. KW - Polylactide KW - MALDI-TOF MS KW - Cyclization KW - Catalyst KW - Catechol KW - Toxicity PY - 2019 DO - https://doi.org/10.1007/s10924-019-01545-5 SP - 10924 PB - Springer AN - OPUS4-49210 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, Hans A1 - Weidner, Steffen T1 - About the influence of salicylic acid on tin(II)octanoate-catalyzed ring opening polymerizationof L-lactide N2 - L-Lactide was polymerized in bulk with tin(II)2-ethylhexanoate SnOct2) as catalyst and salicylic acid as cocatalyst. The Lac/Cat ratio, Cocat/Cat ratio, temperature and time were varied. Increasing Cocat/Cat ratios reduced both,polymerization rate and molecular weight. However,under optimized conditions high molar mass (Mw up to 178,000), colorless, cyclic polylactides were formed in a short time. A few polymerizations performed at 160 and 180°C with the combination of SnOct2 and silylated salicylic acid gave similar results. Neat tin II) salicylate was prepared from SnOct2 and used for REPs of L-lactide in bulk, but the results were not better than those obtained from combinations of SnOct2 and salicylic acid. Furthermore, dibutyltin salicylate was synthesized and used as catalyst for polymerizations of L-lactide in bulk at temperatures varying from 102 to 160°C. Cyclic polylactides with Mw’s up to 40,000 were the main reaction products. At 100–102°C a predominance of odd-numbered cycles was found proving a REP mechanism. KW - Polylactide KW - MALDI-TOF MS KW - Cyclization KW - Catalyst KW - Ring-opening polymerization PY - 2019 DO - https://doi.org/10.1016/j.eurpolymj.2019.07.003 VL - 119 SP - 37 EP - 44 PB - Elsevier Ltd. AN - OPUS4-49211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lee, C. A1 - Inutan, E. D. A1 - Chen, J. L. A1 - Mukeku, M. M. A1 - Weidner, Steffen A1 - Trimpin, S. A1 - Ni, C.-K. T1 - Toward understanding the ionization mechanism of matrix‐assisted ionization using mass spectrometry experiment and theory N2 - Matrix‐assisted ionization (MAI) mass spectrometry does not require voltages, a laser beam, or added heat to initiate ionization, but it is strongly dependent on the choice of matrix and the vacuum conditions. High charge state distributions of nonvolatile analyte ions produced by MAI suggest that the ionization mechanism may be similar to that of electrospray ionization (ESI), but different from matrix‐assisted laser desorption/ionization (MALDI). While significant information is available for MAI using mass spectrometers operating at atmospheric and intermediate pressure, little is known about the mechanism at high vacuum. Eleven MAI matrices were studied on a high‐vacuum time‐of‐flight (TOF) mass spectrometer using a 266 nm pulsed laser beam under otherwise typical MALDI conditions. Detailed comparisons with the commonly used MALDI matrices and theoretical prediction were made for 3‐nitrobenzonitrile (3‐NBN), which is the only MAI matrix that works well in high vacuum when irradiated with a laser. Screening of MAI matrices with good absorption at 266 nm but with various degrees of volatility and laser energies suggests that volatility and absorption at the laser wavelength may be necessary, but not sufficient, criteria to explain the formation of multiply charged analyte ions. 3‐NBN produces intact, highly charged ions of nonvolatile analytes in high‐vacuum TOF with the use of a laser, demonstrating that ESI‐like ions can be produced in high vacuum. Theoretical calculations and mass spectra suggest that thermally induced proton transfer, which is the major ionization mechanism in MALDI, is not important with the 3‐NBN matrix at 266 nm laser wavelength. 3‐NBN:analyte crystal morphology is, however, important in ion generation in high vacuum. The 3‐NBN MAI matrix produces intact, highly charged ions of nonvolatile compounds in high‐vacuum TOF mass spectrometers with the aid of ablation and/or heating by laser irradiation, and shows a different ionization mechanism from that of typical MALDI matrices. KW - Ionization KW - MALDI-TOF MS KW - Mechanism PY - 2021 DO - https://doi.org/10.1002/rcm.8382 VL - 35 IS - 51 SP - e8382 PB - John Wiley & Sons AN - OPUS4-49209 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lüdecke, Nils A1 - Weidner, Steffen A1 - Schlaad, Helmut T1 - Poly(2‐oxazoline) s Based on Phenolic Acids N2 - A series of phenolic-acid-based 2-oxazoline monomers with methoxysubstituted phenyl and cinnamyl side chains is synthesized and polymerized in a microwave reactor at 140 °C using methyl tosylate as the initiator. The obtained poly(2-oxazoline)s are characterized by NMR spectroscopy, MALDITOF mass spectrometry, and size-exclusion chromatography (SEC). Kinetic studies reveal that the microwave-assisted polymerization is fast and completed within less than ≈10 min for low monomer-to-initiator ratios of ≤25. Polymers with number-average molar masses of up to 6500 g mol−1 and low dispersity (1.2–1.3) are produced. The aryl methyl ethers are successfully cleaved with aluminum triiodide/N,N′ diisopropylcarbodiimide to give a poly(2-oxazoline) with pendent catechol groups. KW - 2-oxazoline KW - Catechol KW - Cationic ring opening polymerization KW - Microwave KW - Phenolic acid PY - 2019 DO - https://doi.org/10.1002/marc.201900404 SP - 1900404 PB - Wiley VCH-Verlag AN - OPUS4-49396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholz, Philipp A1 - Ulbricht, Alexander A1 - Joshi, Y. A1 - Gollwitzer, Christian A1 - Weidner, Steffen T1 - Microstructure of polymer-imprinted metal–organic frameworks determined by absorption edge tomography N2 - Mechanochemically synthesized metal–organic Framework material HKUST-1 in combination with acrylonitrile butadiene styrene polymer was used to form a polymer metal–organic framework composite material by a simple extruder. This composite filament was used for 3D printing. Xray diffraction measurements were used to prove the homogeneous distribution of the metal–organic framework in the polymer on a centimeter scale, whereas X-ray Absorption Edge Tomography using a synchrotron radiation source was able to evaluate the 3D distribution of the metal–organic framework material both in the filament and the resultant printed sample with a resolution of a few lm. Our very first data indicate that, apart from a few clusters having significantly higher Cu concentration, HKUST-1 is distributed homogeneously down to the 100 lm length scale in both polymer bulk materials in the form of clusters with a size of a few lm. Absorption Edge Tomography in combination with data fusion also allows for the calculation of the metal–organic framework amount located on the external polymer surface. KW - MOF KW - Polymer KW - AET PY - 2019 DO - https://doi.org/10.3139/146.111817 SN - 1862-5282 SP - 1 EP - 10 PB - Carl Hanser Verlag AN - OPUS4-49483 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 DO - 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 - Kricheldorf, H. A1 - Weidner, Steffen A1 - Meyer, A. T1 - About alcohol-initiated polymerization of glycolide and separate crystallization of cyclic and linear polyglycolides N2 - Alcohol-initiated polymerizations of glycolide (GL) catalyzed by tin(II) 2-ethylhexanoate (SnOct2) were carried out in bulk with variation of GA/In ratio, temperature and time. Due to a rather strong competition of cyclization polyglycolide (PGA) free of cycles were never obtained. When the cyclic catalysts 2,2-dibutal-2-stanna − 1,3-dithiolane (DSTL) or 2-stanna 1,3-dioxo-4,5,6,7 bibenzepane (SnBiph) were used in combination with 1,4-butanediol the influence of cyclization was even stronger. Furthermore, the degrees of polymerization were higher than the GA/alcohol ratio due to rapid polycondensation in the solid state. At 160 °C or below, the matrixassisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra indicated separate crystallization of low molar mass cyclic and linear PGAs from the same reaction mixture (also observed for poly(L-lactide)s). KW - MALDI TOF MS KW - Polyglycolide KW - Ring opening polymerization KW - Cyclization KW - Crystallization PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607282 DO - https://doi.org/10.1016/j.polymer.2024.127440 SN - 0032-3861 VL - 309 SP - 1 EP - 9 PB - Elsevier Ltd. AN - OPUS4-60728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. A1 - Weidner, Steffen A1 - Meyer, A. T1 - Syntheses of high molecular mass polyglycolides via ring-opening polymerization with simultaneous polycondensation(ROPPOC) by means of tin and zinc catalysts N2 - Glycolide was polymerized in bulk by means of four different ROPPOC catalysts: tin(II) 2-ethylhexanoate (SnOct2), dibutyltin bis(pentafluoro-phenoxide) (BuSnOPF),zinc biscaproate (ZnCap), and zinc bis(pentafluoro-phenyl sulfide) (ZnSPF). The temperature was varied between 110 and 180°C and the time between 3 h and 7 days. For the few polyglycolides (PGAs) that were soluble extremely high molecular masses were obtained. The MALDI TOF mass spectra had all a low signal-to-noise ration and displayed the peaks of cyclic PGAs with a“saw-tooth pattern ”indicating formation of extended-ring crystallites in the mass range below m/z 2500. The shape of DSC curves varied considerably with catalyst and reaction conditions, whereas the long-distance values measured by SAXS were small and varied little with the polymeriza-tion conditions. KW - MALDI TOF MS KW - Polyglycolide KW - Crystalinity PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598221 DO - https://doi.org/10.1002/pat.6365 VL - 35 IS - 4 SP - 1 EP - 10 PB - John Wiley & Sons Ltd. AN - OPUS4-59822 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -