TY - CONF A1 - Weidner, Steffen T1 - UV- und IR-MALDI-TOF-MS zur Bestimmung von Molmasse und chemischer Heterogenität von synthetischen Polymeren T2 - 4. Deutsches Bruker Daltonik MALDI-TOF-MS Anwendertreffen CY - Fulda, Germany DA - 1999-04-15 PY - 1999 AN - OPUS4-11282 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - MALDI - Untersuchung zur Oberflächenmodifizierung von Polymeren nach Plasmabehandlung T2 - 4. MALDI-Anwendertreffen (Shimadzu) CY - Duisburg, Germany DA - 1997-11-26 PY - 1997 AN - OPUS4-11280 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - You, Zengchao A1 - Nirmalananthan-Budau, Nithiya A1 - Resch-Genger, Ute A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Separation of polystyrene nanoparticles bearing different carboxyl group densities and functional groups quantification with capillary electrophoresis and asymmetrical flow field flow fractionation N2 - Two sets of polystyrene nanoparticles (PSNPs) with comparable core sizes but different carboxyl group densities were made and separated using asymmetric flow field flow fractionation (AF4), capillary electrophoresis (CE), and the off-line hyphenation of both methods. Our results revealed the significant potential of two-dimensional off-line AF4-CE hyphenation to improve the separation and demonstrated for the first time, the applicability of CE to determine the functional group density of nanoparticles (NPs). Compared to the result acquired with conductometric titration, the result obtained with synthesized 100 nm sized PSNPs revealed only a slight deviation of 1.7%. Commercial 100 nm sized PSNPs yielded a deviation of 4.6 %. For 60 nm sized PSNPs, a larger deviation of 10.6 % between both methods was observed, which is attributed to the lower separation resolution. KW - Nanoparticle KW - A4F KW - Capillary electrophoresis KW - Carboxyl group PY - 2020 DO - https://doi.org/10.1016/j.chroma.2020.461392 VL - 1626 SP - 461392 PB - Elsevier B.V. AN - OPUS4-51080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Meyer, A. A1 - Kricheldorf, H. R. T1 - Sn(II)2-ethylhexanoate-catalyzed polymerizations of L-lactide in solution – Solution grown crystals of cyclic Poly(L-Lactide)s N2 - L-lactide (LA) was polymerized in toluene by means of neat tin(II) 2-ethylhexanoate (SnOct2). Concentration, time and temperature were varied. The isothermally crystallized polyLAs (PLA) were characterized in the virgin state with regard to topology, molar mass, melting temperature (Tm), crystal modification, high or low Tm morphology, crystallinity and crystal thickness. Even a small amount of solvent favored cyclization relative to polymerization in bulk, so that cyclic polylactides were obtained at 115 ◦C and even at 95 ◦C. At all temperatures the α-modification of PLA was obtained along with crystallinities up to 90%. With 6 M solution the high Tm morphology with Tm’s > 190 ◦C was obtained at 115 ◦C. The crystal thickness of crystallites grown from solution at 115 ◦C was on the average 10–20% higher than that of PLA polymerized in bulk. At a polymerization temperature of 75 ◦C cyclization was incomplete and fewer perfect crystallites were formed. A new hypothesis for the crystal growth of cyclic polyLAs is proposed. KW - Polylactide KW - MALDI-TOF MS KW - Crystalinity KW - Polymerization PY - 2022 DO - https://doi.org/10.1016/j.polymer.2022.125142 SN - 0032-3861 VL - 255 SP - 1 EP - 9 PB - Elsevier CY - Oxford AN - OPUS4-55283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hoskins, Jessica A1 - Falkenhagen, Jana A1 - Weidner, Steffen ED - Udomkichdecha, W. ED - Böllinghaus, Thomas ED - Manonukul, A. ED - Lexow, J. T1 - Characterization of randomly branched polymers utilizing liquid chromatography and mass spectrometry N2 - Branching in polymers is an important way to modify the materials properties, however the characterization of random branching in polymeric materials is a challenge in polymer analysis. In this work, liquid adsorption chromatography methods are developed for a commercially available hyperbranched polyester (Boltorn™). This Chromatographie techniques was then coupled to offline MALDI-TOF MS analysis, a first in the analysis of randomly branched polymers. The coupling of these two techniques provides superior MALDI-TOF spectra, enabling the easy identification of structural subdistributons based on theoretical molecular weight. Detailed analysis of the MALDI-TOF spectra shows that these Chromatographie conditions separate cyclic Boltorn polymers (with no core molecule) from non-cyclic polymers (with core molecule), and these are the only two architectures observed. MALDI MS also confirms that the Chromatographie Separation mode is adsorption, but further analysis is needed to determine if there is a Separation by degree of branching. KW - Hyperbranched polyesters KW - Polymer mass spectrometry KW - Polymer chromatography KW - Liquid adsorption chromatography KW - MALDI-TOF MS KW - Carbon capture KW - Climate change KW - Lubricant KW - Micro manufacturing KW - Multiphysics simulations KW - WMRIF PY - 2014 SN - 978-3-319-11339-5 SN - 978-3-319-11340-1 SP - 1 EP - 10 PB - Springer AN - OPUS4-32519 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 - 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 - JOUR A1 - Weidner, Steffen A1 - Trimpin, s. T1 - Mass Spectrometry of Synthetic Polymers KW - Polymere KW - Massenspektrometrie KW - MALDI PY - 2010 DO - https://doi.org/10.1021/ac101080n SN - 0003-2700 SN - 1520-6882 VL - 82 IS - 12 SP - 4811 EP - 4829 PB - American Chemical Society CY - Washington, DC AN - OPUS4-21623 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trimpin, Sarah A1 - Yenchick, Frank S. A1 - Lee, Chuping A1 - Hoang, Khoa A1 - Pophristic, Milan A1 - Karki, Santosh A1 - Marshall, Darrell D. A1 - Lu, I-Chung A1 - Lutomski, Corinne A. A1 - El-Baba, Tarick J. A1 - Wang, Beixi A1 - Pagnotti, Vincent S. A1 - Meher, Anil K. A1 - Chakrabarty, Shubhashis A1 - Imperial, Lorelei F. A1 - Madarshahian, Sara A1 - Richards, Alicia L. A1 - Lietz, Christopher B. A1 - Moreno-Pedraza, Abigail A1 - Leach, Samantha M. A1 - Gibson, Stephen C. A1 - Elia, Efstathios A. A1 - Thawoos, Shameemah M. A1 - Woodall, Daniel W. A1 - Jarois, Dean R. A1 - Davis, Eric T.J. A1 - Liao, Guochao A1 - Muthunayake, Nisansala S. A1 - Redding, McKenna J. A1 - Reynolds, Christian A. A1 - Anthony, Thilani M. A1 - Vithanarachchi, Sashiprabha M. A1 - DeMent, Paul A1 - Adewale, Adeleye O. A1 - Yan, Lu A1 - Wager-Miller, James A1 - Ahn, Young-Hoon A1 - Sanderson, Thomas H. A1 - Przyklenk, Karin A1 - Greenberg, Miriam L. A1 - Suits, Arthur G. A1 - Allen, Matthew J. A1 - Narayan, Srinivas B. A1 - Caruso, Joseph A. A1 - Stemmer, Paul M. A1 - Nguyen, Hien M. A1 - Weidner, Steffen A1 - Rackers, Kevin J. A1 - Djuric, Ana A1 - Shulaev, Vladimir A1 - Hendrickson, Tamara L. A1 - Chow, Christine S. A1 - Pflum, Mary Kay H. A1 - Grayson, Scott M. A1 - Lobodin, Vladislav V. A1 - Guo, Zhongwu A1 - Ni, Chi-Kung A1 - Walker, J. Michael A1 - Mackie, Ken A1 - Inutan, Ellen D. A1 - McEwen, Charles N. T1 - New Processes for Ionizing Nonvolatile Compounds in Mass Spectrometry: The Road of Discovery to Current State-of-the-Art N2 - This Perspective covers discovery and mechanistic aspects aswell as initial applications of novel ionization processes for use in massspectrometry that guided us in a series of subsequent discoveries, instrumentdevelopments, and commercialization. Vacuum matrix-assisted ionization onan intermediate pressure matrix-assisted laser desorption/ionization sourcewithout the use of a laser, high voltages, or any other added energy wassimply unbelievable, at first. Individually and as a whole, the variousdiscoveries and inventions started to paint, inter alia, an exciting new pictureand outlook in mass spectrometry from which key developments grew thatwere at the time unimaginable, and continue to surprise us in its simplisticpreeminence. We, and others, have demonstrated exceptional analyticalutility. Our current research is focused on how best to understand, improve, and use these novel ionization processes throughdedicated platforms and source developments. These ionization processes convert volatile and nonvolatile compounds from solid orliquid matrixes into gas-phase ions for analysis by mass spectrometry using, e.g., mass-selected fragmentation and ion mobilityspectrometry to provide accurate, and sometimes improved, mass and drift time resolution. The combination of research anddiscoveries demonstrated multiple advantages of the new ionization processes and established the basis of the successes that lead tothe Biemann Medal and this Perspective. How the new ionization processes relate to traditional ionization is also presented, as wellas how these technologies can be utilized in tandem through instrument modification and implementation to increase coverage ofcomplex materials through complementary strengths. KW - Mass spectrometry PY - 2024 DO - https://doi.org/10.1021/jasms.3c00122 SN - 1879-1123 VL - 35 IS - 12 SP - 2753 EP - 2784 PB - American Chemical Society (ACS) AN - OPUS4-61417 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholz, Philipp A1 - Wachtendorf, Volker A1 - Elert, Anna Maria A1 - Falkenhagen, Jana A1 - Becker, Roland A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Tschiche, Harald A1 - Reinsch, Stefan A1 - Weidner, Steffen ED - Scholz, Philipp T1 - Analytical toolset to characterize polyurethanes after exposure to artificial weathering under systematically varied moisture conditions N2 - Polyether and -ester urethanes (PU) were exposed to artificial weathering at 40 °C and artificial UV radiation in a weathering chamber. In 3 parallel exposures, humidity was varied between dry, humid, and wet conditions. Material alteration was investigated by various analytical techniques like size exclusion chromatography (SEC), liquid chromatography-infrared spectroscopy (LC-FTIR), thermal-desorption gas chromatography-mass spectrometry (TD-GC-MS), fluorescence mapping and dynamic mechanical analysis (DMA). Our results show that depending on the weathering conditions, different degradation effects can be observed. By means of SEC an initial strong decrease of the molar masses and a broadening of the mass distributions was found. After a material dependent time span this was followed by a plateau where molar mass changes were less significant. A minor moisture-dependent degradation effect was only found for polyester PU. Fluorescence measurements on two materials revealed an increase in the luminescence intensity upon weathering process reaching a saturation level after about 500 h. The changes in the optical properties observed after different exposure conditions and times were very similar. The TD-GC-MS data showed the fate of the stabilizers and antioxidant in the course of weathering. LC-FTIR measurements revealed a change in peak intensities and the ratio of urethane and carbonyl bands. KW - Polyurethane KW - Artificial weathering KW - Moisture KW - Crosslinking KW - Degradation PY - 2019 UR - https://www.sciencedirect.com/science/article/pii/S0142941819303708 DO - https://doi.org/10.1016/j.polymertesting.2019.105996 SN - 0142-9418 VL - 78 SP - 105996, 1 EP - 9 PB - Elsevier CY - Amsterdam AN - OPUS4-48625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H.R. A1 - Mix, Renate A1 - Weidner, Steffen T1 - Poly(ester urethane)s derived from lactide, isosorbide, terephthalic acidm abd various diisocyanates N2 - Isosorbide-initiated oligomerizations of ʟ-lactide were preformed in bulk using SnCl2 as catalyst. The resulting telechelic OH-terminated oligoesters were in situ subjected to simultaneous polycondensation and polyaddition with mixtures of terephthaloyl chloride and diisocyanates. Most polymerizations were conducted with 4,4'-diisocyanatodiphenyl methane and 2,4-diisocyanato toluene. The consequences of excess diisocyanate and four different catalysts were studied. The isosorbide/lactide ratio and the terephthalic acid/diisocyanate ratio were varied. Number average molecular weights up to 15 kDa with polydispersities around 3–5 were obtained. Depending on the chemical structure of the copolyester and on the feed ratio, incorporation of urethane groups may reduce or enhance the glass-transition temperature, but the thermal stability decreases dramatically regardless of composition. KW - Cyclization KW - Isosorbide KW - Lactide KW - Polyaddition KW - Polycondensation KW - Polyesters KW - Polyurethanes PY - 2014 DO - https://doi.org/10.1002/pola.27069 SN - 0360-6376 SN - 0887-624X VL - 52 IS - 6 SP - 867 EP - 875 PB - Wiley CY - Hoboken, NJ AN - OPUS4-30299 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -