TY - CONF A1 - Weidner, Steffen T1 - MALDI-TOF Massenspektrometrie von Polymeren - Anwendungen, Probleme, Trends T2 - Kolloquium zum Thema "Untersuchungen von synthetischen bzw. Biopolymeren mit MALDI-TOF-MS" CY - Dresden, Germany DA - 2009-12-10 PY - 2009 AN - OPUS4-20151 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - Sample spot heterogeneity investigated by MALDI-imaging mass spectrometry T2 - 18th International Mass Spectrometry Conference CY - Bremen, Germany DA - 2009-08-30 PY - 2009 AN - OPUS4-19989 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - Cyclic polylactides via ring-expansion polymerization N2 - We will report on a new kind of ring-expansion polymerization (REP) of cyclic esters based of three classes of catalysts. In contrast to REP described previously these new polymerizations are characterized by a self-extrusion of the catalysts resulting in cyclic homopolyesters as the only reaction product. These REP of L-lactide were performed in bulk at temperatures between 100 and 180°C without racemization. A simplified scheme of a REP catalyzed by BuCa or SnBi is presented below. With meso-lactide temperatures down to 60°C were realized. Depending on catalyst, time and temperature with equal quantities of even and odd-numbered cycles a strong predominance of either even or odd-numbered cycles was found. T2 - 255th ACS National Meeting CY - New Orleans, LA, USA DA - 18.03.2018 KW - MALDI-TOF MS KW - Poly(lactide) KW - Polymerisation KW - Catalysts PY - 2018 AN - OPUS4-44833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - MALDI-TOF MS von ultra-hochmolekularen Polystyrolen mittels DCTB und Cäsium-Salzen T2 - 19. Kolloquium MALDI und Synthetische Polymere CY - Berlin DA - 2015-05-12 PY - 2015 AN - OPUS4-33055 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - MALDI-TOF Imaging Mass Spectrometry - an universal detector for copolymer chromatography T2 - ASMS-Conference on Mass Spectrometry CY - Denver, CO, USA DA - 2011-06-04 PY - 2011 AN - OPUS4-23732 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - Charakterisierung der molekularen und chemischen Heterogenität von Polyoxymethylen (POM) T2 - BASF CY - Ludwigshafen am Rhein, Germany DA - 2005-06-17 PY - 2005 AN - OPUS4-11143 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Just, Ulrich T1 - Principle of Two-Dimensional Characterization of Copolymers N2 - Two-dimensional polymer characterization is used for a simultaneous analysis of molar masses and chemical heterogeneities (e.g., end groups, copolymer composition, etc.). This principle is based on coupling of two different chromatographic modes. Liquid adsorption chromatography at critical conditions (LACCC) is applied for a separation according to the chemical heterogeneity, whereas in the second-dimension fractions are analyzed with regard to their molar mass distribution by means of size exclusion chromatography (SEC). Because appropriate standards for a calibration of the SEC are seldom available, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) was used to substitute the SEC. The LACCC-MALDI MS coupling enables acquiring additional structural information on copolymer composition, which can considerably enhance the performance of this coupled method. KW - MALDI-TOF MS KW - Chromatographie KW - Kopplung PY - 2007 DO - https://doi.org/10.1021/ac062145f SN - 0003-2700 SN - 1520-6882 VL - 79 IS - 13 SP - 4814 EP - 4819 PB - American Chemical Society CY - Washington, DC AN - OPUS4-17722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Jörg Florian A1 - Schulz, Eckhard A1 - Weidner, Steffen A1 - Kühn, Gerhard T1 - Improvement in Mechanical Strength of Fibre Polymer Composites by Fibre Pretreatment in Low-Pressure Plasmas T2 - Vortragsbände des 8. Internationalen Techtextil-Symposiums 1997 CY - Frankfurt am Main, Deutschland DA - 1997-05-12 PY - 1997 SP - 1(?) EP - 16(?) PB - Messe Frankfurt CY - Frankfurt am Main AN - OPUS4-7286 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - Sample spot heterogeneity investigated by MALDI-imaging mass spectrometry T2 - 57th ASMS Conference On Mass Spectrometry and Allied Topics CY - Philadelphia, PA, USA DA - 2009-05-31 PY - 2009 AN - OPUS4-19191 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Polymer Characterization by LC / MALDI-MS Coupling T2 - Vortragstagung "Funktionspolymere für Systemlösungen" CY - Darmstadt, Germany DA - 2002-03-18 PY - 2002 AN - OPUS4-1805 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - ^Mass spectrometry of synthetic polymers applications and limitations of the MALDI-TOF technique T2 - APST 2 (Advances in Polymer Science and Technology) CY - Linz, Austria DA - 2011-09-28 PY - 2011 AN - OPUS4-25271 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -