TY - GEN A1 - Reuther, F. A1 - Krüger, Ralph-Peter A1 - Schulz, Günter A1 - Baehr, G. A1 - Westerwelle, U. A1 - Gruetzner, G. ED - Houlihan, F. M. T1 - Tailored novolak resins for advanced photoresists by a two-step procedure - new insight into the molecular structure by coupling GPC and MALDI-TOF-MS T2 - Advances in resist technology and processing XVII T2 - 17th Annual SPIE Conference on Advances in Resist Technology and Processing CY - Santa Clara, CA, USA DA - 2000-02-28 KW - Novolak KW - Structure KW - Synthesis KW - Gel permeation KW - Chromatography KW - MALDI-TOF-MS PY - 2000 SN - 0-8194-3617-8 SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series IS - 3999 SP - 464 EP - 471 PB - SPIE CY - Bellingham AN - OPUS4-2171 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shaik, A.-A. A1 - Richter, M. A1 - Kricheldorf, H. A1 - Krüger, Ralph-Peter T1 - New polymer syntheses - CIX. Biodegradable, alternating copolyesters of terephthalic acid, aliphatic dicarboxylic acids, and alkane diols JF - Journal of polymer science A, polymer chemistry N2 - Copolyesters with an alternating sequence of terephthalic acid and aliphatic dicarboxylic acids were prepared with three different methods. First, dicarboxylic acid dichlorides were reacted with bis(2-hydroxyethyl)terephthalate (BHET) in refluxing 1,2-dichlorobenzene. Second, the same monomers were polycondensed at 0-20 °C in the presence of pyridine. Third, dicarboxylic acid dichlorides and silylated BHET were polycondensed in bulk. Only this third method gave satisfactory molecular weights. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry revealed that the copolyesters prepared by the pyridine and silyl methods might have contained considerable fractions of cyclic oligoesters and polyesters despite the absence of transesterification and backbiting processes. The alternating sequences and thermal properties were characterized with 1H NMR spectroscopy and differential scanning calorimetry measurements, respectively. In agreement with the alternating sequence, all copolyesters proved to be crystalline, but the crystallization was extremely slow [slower than that of poly(ethylene terephthalate)]. A second series of alternating copolyesters was prepared by the polycondensation of silylated bis(4-hydroxybut- yl)terephthalate with various aliphatic dicarboxylic acid dichlorides. The resulting copolyesters showed significantly higher rates of crystallization, and the melting temperatures were higher than those of the BHET-based copolyesters. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3371-3382, 2001 KW - Poly(ethylene terephthalate) KW - Poly(butylene terephthalate) KW - Alternating sequence KW - Macrocycles KW - Crystallization KW - Biodegradable polyesters PY - 2001 DO - https://doi.org/10.1002/pola.1320 SN - 0360-6376 SN - 0887-624X VL - 39 IS - 19 SP - 3371 EP - 3382 PB - Wiley CY - Hoboken, NJ AN - OPUS4-2173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bünger, H. A1 - Krüger, Ralph-Peter A1 - Pietschmann, S. A1 - Wüstneck, N. A1 - Kaufner, L. A1 - Tschiersch, R. A1 - Pison, U. T1 - Two hydrophobic protein fractions of ovine pulmonary surfactant: Isolation, characterisation and biophysical activity JF - Protein expression and purification N2 - Pulmonary surfactant contains two extremely hydrophobic proteins, SP-B and SP-C. We present a novel HPLC method for the preparation of these hydrophobic proteins. It is based on size-exclusion chromatography using the apolar stationary-phase butyl silica gel and isocratic elution with acidified chloroform/methanol. Samples for HPLC were prepared from sheep lung lavage fluid by centrifugation and extraction with chloroform/methanol. Amino acid analyses of the two protein fractions revealed sequences that are consistent with SP-B and SP-C, respectively. MALDI-TOF-MS analyses of the SP-B fraction showed one major peak of dimeric SP-B with m/z 17,361, and additional peaks of monomeric and oligomeric forms, which are predominantly even numbered. The SP-C fraction showed a peak at m/z 4200, consistent with the theoretical mass of the dipalmitoylated form of this protein. The biophysical activity of pure sheep SP-B and SP-C was evaluated by measuring the surface tension using axisymmetric drop shape analysis for captive bubbles. We found distinct surface pressure versus surface area isotherms of SP-B and SP-C indicating different biophysical activities for these surfactant proteins. The new preparative HPLC method is able to replace the established, time-consuming low-pressure liquid chromatography method for the isolation of SP-B and SP-C from lipids. KW - Surfactant proteins KW - SP-B KW - SP-C KW - Preparative HPLC KW - MALDI-TOF-MS KW - Surface pressure KW - Captive bubble PY - 2001 DO - https://doi.org/10.1006/prep.2001.1510 SN - 1046-5928 SN - 1096-0279 VL - 23 IS - 2 SP - 319 EP - 327 PB - Elsevier CY - Amsterdam AN - OPUS4-2174 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Czichocki, G. A1 - Heger, R. A1 - Much, Helmut A1 - Krüger, Ralph-Peter A1 - Goedel, W.A. T1 - Synthesis of Polyisoprenes with Sulfonate Head Groups and their Purification by HPLC JF - Tenside, surfactants, detergents PY - 2001 SN - 0932-3414 SN - 0040-3490 VL - 38 IS - 3 SP - 168 EP - 172 PB - Hanser CY - München AN - OPUS4-2175 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H.R. A1 - Böhme, S. A1 - Schwarz, G. A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Macrocycles 18. The Role of Cyclization in Syntheses of Poly(ether-sulfone)s JF - Macromolecules N2 - Poly(ether-sulfone)s having an identical backbone were prepared by four different methods. First, silylated bisphenol A (BSBA) was polycondensed with 4,4'-difluorodiphenyl sulfone (DFDPS) and K2CO3 in N-methylpyrrolidone with variation of the temperature. Second, analogous polycondensation were conducted using CsF as catalyst (and no K2CO3). Third, CsF-catalyzed polycondensations BSBA and DFDPS were conducted in bulk up to 290 C. Fourth, free bisphenol was polycondensed with DFDPS or 4,4'-dichlorodiphenyl sulfone and K2CO3 in DMSO with azeotropic removal of water. MALDI-TOF mass spectroscopy revealed that the first method mainly yielded cyclic poly(ether-sulfone)s which were detected up to masses around 13 000 Da. These and other results suggest that these polycondensations take a kinetically kontrolled course at tempeatures 145 C. This interpretation is also valid for the fourth method where high yields of cycles were obtained with DFDPS. With the less reactive 4,4'-dichlorodiphenyl sulfone lower conversions, lower molecular weights and lower fractions of cycles were found. In contrast to KF (resulting from K2CO3) CsF cleaves the poly(ether sulfone) backbone at temperatures > 145 C. Smaller amounts of smaller cycles were found in these CsF-catalyzed polycondensations which were in this case the result of thermodynamically controlled "back-biting degradation". PY - 2001 DO - https://doi.org/10.1021/ma010218l SN - 0024-9297 SN - 1520-5835 VL - 34 SP - 8886 EP - 8893 PB - American Chemical Society CY - Washington, DC AN - OPUS4-2176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H.R. A1 - Rabenstein, M. A1 - Langanke, D. A1 - Schwarz, G. A1 - Schmidt, M. A1 - Maskos, M. A1 - Krüger, Ralph-Peter T1 - Ring-closing polycondensations JF - High performance polymers N2 - The role of cyclization in polycondensations is discussed for two different scenarios: thermodynamically-controlled polycondensation (TCPs) on the one hand and kinetically-controlled polycondensations (KCPs) on the other. The classical Carothers–Flory theory of step-growth polymerization does not include cyclization reactions. However, TCPs involve the formation of cycles via ‘back-biting degradation’, and when the ring–chain equilibrium is on the side of the cycles the main reaction products of the TCP will be cyclic oligomers. Two groups of examples are discussed: polycondensations of salicyclic acid derivatives (e.g. aspirin) and polycondensations of dibutyltin derivatives with long {alpha}-, {omega}-diols or dicarboxylic acids. Furthermore, various kinetically-controlled syntheses of polyesters and polyamides were studied and carefully optimized in the direction of high molecular weights. High fractions of cyclic oligomers and polymers were found by MALDI-TOF mass spectrometry, and their fractions increased with optimization of the process for molecular weight. These results disagree with the Carothers–Flory theory but agree with the theoretical background of the Ruggli–Ziegler dilution method (RZDM). When poly(ether-sulfone)s were prepared from 4,4'-difluorodiphenylsulfone and silylated bisphenol-A two different scenarios were found. With CsF as catalyst at a temperature of more than 145°C cyclic oligoethers were formed under thermodynamic control. When the polycondensation was promoted with K2CO3 in N-methylpyrolidone at ?145°C the formation of cyclic oligoethers and polyethers occurred under kinetic control. A new mathematical formula is presented correlating the average degree of polymerization with the conversion and taking into account the competition between cyclization and propagation. PY - 2001 DO - https://doi.org/10.1088/0954-0083/13/2/312 SN - 0954-0083 SN - 1361-6412 VL - 13 SP - S123 EP - S136 PB - Sage Publ. CY - London AN - OPUS4-2178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Janiak, Ch. A1 - Lange, K.C.H. A1 - Marquardt, P. A1 - Krüger, Ralph-Peter A1 - Hanselmann, R. T1 - Analyses of Propene and 1-Hexene Oligomers from Zirconocene/MAO Catalysts - Mechanistic Implications by NMR, SEC and MALDI-TOF MS JF - Macromolecular chemistry and physics N2 - A series of Cp(C5H5)ZrCl2 and Cp2ZrCl2 pre-catalysts (Cp = C5HMe4, C4Me4P, C5Me5, C5H4tBu, C5H3-1,3-tBu2, C5H2-1,2,4-tBu3) together with (C5H5)2ZrCl2 was used for the directed oligomerization of propene and 1-hexene in comparative experiments. Oligomer characterization was carried out by 1H NMR, SEC (GPC), MALDI-TOF MS, cryoscopy and Raman spectroscopy. From 1H NMR the nature and relative ratio of the double-bond end group is determined together with n if every oligomer molecule contains such a double-bond end group. Normally vinylidene double bonds (from -hydrogen elimination) are found. From 1H NMR and MALDI-TOF MS also vinyl end groups (from -methyl elimination) are observed in the case of oligopropenes with (C4Me4P)- (C5H5)ZrCl2 and with the symmetrical methyl containing Cp2ZrCl2 pre-catalysts. The vinylidene/vinyl ratio depends on the ligand and increases from C5HMe4 (65/35) over C4Me4P (61/39) to C5Me5 (9/91). A comparison of n from 1H NMR and SEC together with MALDI-TOF MS shows that the phospholyl-zirconocenes and (C5HMe4)2ZrCl2 also exhibit chain transfer to aluminium, thereby giving saturated oligomers. KW - Chain transfer KW - MALDI KW - Metallocene catalysts KW - Oligomers KW - Polyolefins PY - 2002 DO - https://doi.org/10.1002/1521-3935(20020101)203:1<129::AID-MACP129>3.0.CO;2-C SN - 1022-1352 SN - 1521-3935 VL - 203 IS - 1 SP - 129 EP - 138 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-2179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Tressl, R. A1 - Kersten, E. A1 - Wondrak, G. T. A1 - Rewicki, D. A1 - Krüger, Ralph-Peter ED - O'Brien, J. T1 - Fragmentation of Sugar Skeletons and Formation of Maillard Polymers T2 - The Maillard reaction in foods and medicine T2 - 6th International Symposium on the Maillard Reaction CY - London, England, UK DA - 1997-07-27 PY - 1998 SN - 0-85404-733-6 SN - 0260-6291 N1 - Serientitel: Special publication / Royal Society of Chemistry – Series title: Special publication / Royal Society of Chemistry IS - 223 SP - 69 EP - 75 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-2161 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Veith, M. A1 - Elsässer, R. A1 - Krüger, Ralph-Peter T1 - Synthesis of Dendrimers with a N-Si-C Framework JF - Organometallics N2 - A novel family of air-stable dendrimers with a N-Si-C framework has been prepared up to the fourth generation. The divergent synthesis starts with the hydrosilylation of the trisilazane N(SiMe2vinyl)3 [0-G(vinyl)] by HSiMe2Cl, which gives the three-directional core molecule N(SiMe2CH2CH2SiMe2Cl)3 [0-G(Cl)]. A 1-to-2 branching achieved by reacting the core molecule [0-G(Cl)] with 3 equiv of KN(SiMe2vinyl)2 affords the first generation dendrimer [1-G(vinyl)]. By repeating the above two steps, the second [2-G(vinyl)], third [3-G(vinyl)], and fourth generation [4-G(vinyl)] can be obtained. The compounds have been characterized by 1H, 13C, and 29Si NMR spectroscopy, by elemental analysis, and up to the third generation by MALDI-TOF mass spectrometry. Gel permeation chromatography was used to prove the fourth generation [4-G(vinyl)]. PY - 1999 DO - https://doi.org/10.1021/om9807708 SN - 0276-7333 SN - 1520-6041 VL - 18 IS - 4 SP - 656 EP - 661 PB - American Chemical Society CY - Washington, DC AN - OPUS4-2162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Friedrich, Jörg Florian A1 - Krüger, Ralph-Peter A1 - Schulz, Günter A1 - Much, Helmut T1 - Liquid Adsorption Chromatography near Critical Conditions of Adsorption coupled with Matrix-assisted Laser/Ionization Mass Spectrometry T2 - Proceedings of the 47th ASMS Conference on Mass Spectrometry and Allied Topics T2 - 47th ASMS Conference on Mass Spectrometry and Allied Topics CY - Dallas, TX, USA DA - 1999-06-13 PY - 1999 CY - Dallas, Tex AN - OPUS4-2165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H.R. A1 - Eggerstedt, S. A1 - Krüger, Ralph-Peter T1 - Macrocycles, 6a / MALDI-TOF mass spectrometry of tin-initiated macrocyclic polylactones in comparison to classical mass-spectroscopic methods JF - Macromolecular chemistry and physics PY - 1999 SN - 1022-1352 SN - 1521-3935 VL - 200 IS - 6 SP - 1284 EP - 1291 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-2166 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. A1 - Hauser, K. A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Macrocycles 12. Ring-Opening Polycondensations of Tin-Containing Macrocycles with Bis(Thioarylester)s JF - Journal of macromolecular science A N2 - 2,2-Dibutyl-2-stanna-1,3-dioxepane (DSDOP) was polycondensed with bis(4-chlorothiophenyl) suberat under various reaction conditions, but only moderate molecular weights (Mn 10000) were obtained. The MALDI-TOF mass spectrosmetry revealed the formation of cyclic oligo- and polyesters in addition to linear species having OH, CO2H, and unreacted 4-chlorothiophenyl ester endgroups. Furthermore, -Caprolactone (-CL) was polymerized with DSDOP as the initiator at monomer/initiator (M/I) ratios of 20 and 50. The resulting tin-containing macrocyclic polylactones were reacted with sebacic acid bis(4-thiocresyl)ester at three different temperatures and with different reaction times. Analogous polycondensations were conducted with suberic acid bis(4-chlorothiophenyl) ester. The presence of thioarylester endgroups in the isolated polyesters was checked by 1H NMR spectroscopy. The highest conversions were found at long reaction times (24 or 72 hours), or after the addition of pyridine and N,N-dimethylaminopyridine as catalysts. Despite high conversions, the number average molecular weights (Mn's) did not exceed values around 20000. Even in the samples having the highest molecular weights, unreacted 4-chlorothiophenylester endgroups were detected by GPC measurements evaluated with a UV-detector. It is concluded that both factors, cyclization and incomplete conversion, contribute to the limitation of the chain growth. KW - Ring-Opening Polycondensations KW - Macrocycles KW - Polyesters PY - 2000 DO - https://doi.org/10.1081/MA-100101099 SN - 1060-1325 SN - 1520-5738 VL - 37 IS - 4 SP - 379 EP - 394 PB - Taylor & Francis CY - Philadelphia, PA AN - OPUS4-2167 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Friedrich, Jörg Florian A1 - Schulz, Günter A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Weidner, Steffen T1 - Liquid Adsorption Chromatography near Critical Conditions of Adsorption coupled with Matrix-assisted Laser Desorption/Ionization Mass Spectrometry JF - International journal of polymer analysis and characterization N2 - Chemical heterogeneities and molecular weight distributions of poly(ethylene oxide) (PEO)-co-polymethylene (PM) model oligomers, which are relevant to the synthesis of commonly used tensides, were investigated. For analytical characterization, the well-known principle of liquid adsorption chromatography at 'critical conditions' (LACCC) was modified. Near the critical conditions of adsorption of the PEO unit, e.g., at slight adsorption conditions of PM, the copolymers could be separated according to their PM chain length. The eluates were separated and single fractions of each peak were continuously transferred onto the MALDI target by means of a commercially available device. Simultaneously, the MALDI matrix solution was continuously added with a second pump. This procedure offers the possibility of the formation of homogeneous matrix-polymer textures. By MALDI-MS a complete characterization of the chemical composition (PEO and PM chain length) of each peak could be achieved. The obtained MALDI mass spectra of the eluates at different retention times could be used for the molecular weight calibration of the LAC system. In this way, an additional application of SEC, as in conventional 2D-chromatography, was avoided by using the MALDI method as quasi chromatographic separation KW - Liquid adsorption chromatography KW - Matrix-assisted laser desorption KW - Ionization mass spectrometry KW - Coupling methods KW - MALDI PY - 2000 DO - https://doi.org/10.1080/10236660008034644 SN - 1023-666X SN - 1563-5341 VL - 5 SP - 549 EP - 562 PB - Gordon and Breach Publ. CY - Amsterdam AN - OPUS4-2168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Krüger, Ralph-Peter A1 - Friedrich, Jörg Florian T1 - Determination of chemical and molecular-weight distributions of heterogeneous polymers by means of MALDI-MS coupled with chromatography JF - Polymer preprints T2 - 219th ACS national meeting CY - San Francisco, CA, USA DA - 2000-03-26 PY - 2000 SN - 0032-3934 VL - 41 IS - 1 SP - 655 EP - 656 PB - American Chemical Society CY - Newark, NJ AN - OPUS4-2169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. A1 - Probst, N. A1 - Schwarz, G. A1 - Schulz, Günter A1 - Krüger, Ralph-Peter T1 - New Polymer Syntheses - 107. Aliphatic Poly(thio ester)s by Ring-Opening Polycondensation of 2-Stanna-1,3-Dithiacycloalkanes JF - Journal of polymer science A, polymer chemistry N2 - We prepared 2,2-dibutyl-2-stanna-1,3-dithiacycloalkanes from dibutyltin oxide and ,-dimercaptoalkanes. Heterocycles with five-, six-, seven-, or nine-ring members were used as bifunctional monomers for polycondensations with aliphatic dicarboxylic acid chlorides. These polycondensations conducted in bulk were highly exothermic and yielded poly(thio ester)s with number average molecular weights (Mn's) in the range of 5000-30,000 Da. These poly(thio ester)s proved to be rapidly crystallizing materials with melting temperatures in the range of 90-150 °C. In addition to the success of the new synthetic approach, two interesting and unpredictable results were obtained. All volatile species detectable by matrix assisted laser desorption induced-time of flight (MALDI-TOF) mass spectrometry were cyclic oligo- and poly(thio ester)s. Second, several polyesters showed a reversible first-order change of the crystal modification as identified by differential scanning calorimetry measurements and X-ray scattering with variation of the temperature. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3656-3664, 2000 KW - Poly(thio-ester)s KW - Ring-opening polycondensation KW - Macrocycles KW - Change of crystal structure PY - 2000 DO - https://doi.org/10.1002/1099-0518(20001001)38:19<3656::AID-POLA190>3.0.CO;2-M SN - 0360-6376 SN - 0887-624X VL - 38 IS - 19 SP - 3656 EP - 3664 PB - Wiley CY - Hoboken, NJ AN - OPUS4-2170 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlaad, H. A1 - Müller, A. A1 - Spickermann, J. A1 - Räder, H. A1 - Krüger, Ralph-Peter T1 - Quantitative Analysis of Molecular Weight Distribution Obtained by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) T2 - Second International Conference on Molecular Mass Characterization of Synthetic and Natural Polymers T2 - 2nd International Conference on Molecular Mass Characterization of Synthetic and Natural Polymers CY - Bradford, England, UK DA - 1996-04-01 PY - 1996 CY - Bradford AN - OPUS4-2218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gähde, J. A1 - Mix, Renate A1 - Krüger, Ralph-Peter A1 - Goering, Harald A1 - Funke, W. A1 - Hermann, U. T1 - Adherence of Liquid Crystalline TDI-Polyurethanes to Steel JF - The journal of adhesion KW - Main-chain liquid crystalline polyurethanes KW - Primer on steel KW - Pull-off test KW - Wet adhesion of alkyd melamine resin KW - Mesogenic unit KW - Glass transition temperature KW - Hard segments KW - Soft segments PY - 1996 SN - 0021-8464 SN - 1545-5823 VL - 58 SP - 243 EP - 251 PB - Gordon & Breach CY - New York, NY AN - OPUS4-2152 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spickermann, J. A1 - Martin, K. A1 - Räder, H.J. A1 - Müllen, K. A1 - Schlaad, H. A1 - Müller, A. H. E. A1 - Krüger, Ralph-Peter T1 - Quantitative analysis of broad molecular weight distributions obtained by MALDI-TOF mass spectrometry JF - European journal of mass spectrometry PY - 1996 SN - 1469-0667 SN - 1356-1049 SN - 1365-0718 IS - 2 SP - 161 EP - 165 PB - IM Publications CY - Chichester AN - OPUS4-2153 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wachsen, O. A1 - Reichert, K.H. A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Thermal decomposition of biodegradable polyesters - III. Studies on the mechanisms of thermal degradation of oligo-L-lactide using SEC, LACCC and MALDI-TOF-MS JF - Polymer degradation and stability PY - 1997 SN - 0141-3910 SN - 1873-2321 VL - 55 SP - 225 EP - 231 PB - Applied Science Publ. CY - London AN - OPUS4-2154 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tressl, R. A1 - Wondrak, G. T. A1 - Krüger, Ralph-Peter A1 - Rewicki, D. T1 - New Melanoidin-like Maillard Polymers from 2-Deoxypentoses JF - Journal of agricultural and food chemistry KW - Maillard system 2-deoxy-D-ribose / methylamine KW - Oligomerization of N-methyl-2-hydroxymethyl(and hydroxyl[13C]methyl)pyrrole KW - Antioxidative activity KW - Model compounds for melanoidins PY - 1998 SN - 0021-8561 SN - 1520-5118 VL - 46 IS - 1 SP - 104 EP - 110 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-2158 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tressl, R. A1 - Wondrak, G. T. A1 - Garbe, L.-A. A1 - Krüger, Ralph-Peter A1 - Rewicki, D. T1 - Pentoses and Hexoses as Sources of New Melanoidin-like Maillard-Polymers JF - Journal of agricultural and food chemistry KW - Model compounds for melanoidins KW - Pyrroles from pentoses and hexoses KW - Beta-dicarbonyl pathway of the Maillard reaction KW - Polycondensation KW - MALDI-TOF-MS analysis KW - Antioxidative activity of oligomeric model compounds PY - 1998 SN - 0021-8561 SN - 1520-5118 VL - 46 IS - 5 SP - 1765 EP - 1776 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-2159 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Tressl, R. A1 - Wondrak, G. T. A1 - Kersten, E. A1 - Krüger, Ralph-Peter A1 - Rewicki, D. ED - Shibamoto, T. ED - Terao, J. ED - Osawa, T. T1 - Identification of maillard type polymers with antioxidative activity T2 - Medical plants and other foods T2 - 213th National Meeting of the American Chemical Society CY - San Francisco, CA, USA DA - 1997-04-13 PY - 1998 SN - 0-8412-3573-2 SN - 0097-6156 N1 - Serientitel: ACS Symposium Series – Series title: ACS Symposium Series IS - 702 SP - 209 EP - 220 PB - American Chemical Society CY - Washington, DC AN - OPUS4-2160 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H.R. A1 - Böhme, S. A1 - Krüger, Ralph-Peter T1 - Macrocycles, 16a - Macrocyclic Dibutyltin Dicarboxylates via Thermodynamically Controlled Polycondensations JF - Macromolecular chemistry and physics N2 - Various dibutyltin derivatives were polycondensed with aliphatic ,-dicarboxylic acids having chain lengths from 4 (succinic acid) to 22 carbon atoms. White crystalline products were obtained from all experiments, and the structure of the products was independent of the synthetic method. Viscosity measurements revealed low molecular weights (n 1 500 Da) in all cases. Vapor pressure osmometry (VPO) measurements and matrix-assisted laser desorption time-of-flight (MALDI-TOF) mass spectrometry proved that cyclic dimers and trimer were formed from dicarboxylic acids having 6 to 16 carbons, but mainly the monomeric cycle from docosane dioic acid. Heating to 250°C did not change the structure. Therefore, the results indicate that the macrocycles are the result of a thermodynamically controlled ring-closing polycondensation. This means that linear high-molecular weight poly(dibutyltin dicarboxylate)s cannot exist above room temperature. KW - Macrocyclics KW - MALDI KW - Oligomers KW - Polycondensation KW - Thermodynamics PY - 2002 SN - 1022-1352 SN - 1521-3935 VL - 203 IS - 2 SP - 313 EP - 318 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-2181 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Jancke, Harald A1 - Krüger, Ralph-Peter A1 - Rikowski, Eckhard A1 - Schulz, Günter T1 - Characterization of Silsesquioxanes by Size-exclusion chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry JF - Rapid communications in mass spectrometry N2 - Liquid chromatography in combination with spectroscopic methods like matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) or nuclear magnetic resonance (NMR) spectroscopy is a powerful method to characterize silsesquioxanes and silsesquioxane mixtures. As new examples, the formation of silsesquioxyl-substituted silsesquioxanes [(n-octyl)7(SiO1.5)8]2O and [(n-octyl)7(SiO1.5)8O]2[(n-octyl)6(SiO1.5)8] as well as the cage rearrangement of octa-[(n-heptyl)silsesquioxane] to larger structur es [(n-heptyl)SiO1.5)]n up to n=28 are shown. PY - 2003 DO - https://doi.org/10.1002/rcm.911 SN - 0951-4198 SN - 1097-0231 VL - 17 IS - 4 SP - 285 EP - 290 PB - Wiley CY - Chichester AN - OPUS4-2182 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kilz, P. A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter ED - Provder, T. T1 - Two-dimensional chromatography for the deformulation of complex copolymers T2 - Chromatographic characterization of polymers PY - 1995 SN - 0-8412-3132-X N1 - Serientitel: Advances in chemistry series – Series title: Advances in chemistry series IS - 247 SP - 223 EP - 241 PB - American Chemical Society CY - Washington AN - OPUS4-2185 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Just, Ulrich A1 - Krüger, Ralph-Peter ED - Auner, N. T1 - Investigations of Chemical Heterogeneity in Polydimethylsiloxanes using SFC, HPLC and MALDI-MS T2 - Organosilicon chemistry II T2 - 2. Münchner Silicontage ; 2nd Munich Silicon Days CY - Munich, Germany DA - 1994-01-01 PY - 1996 SN - 3-527-29254-3 SP - 625 EP - 632 PB - VCH CY - Weinheim AN - OPUS4-2186 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Rikowski, E. ED - Auner, N. T1 - Synthesis of Polyhedral Hexa-, Octa-, Deca- and Dodeca-Silsesquioxanes, Separation by NP-HPLC, SEC and LAC, Characterization by MALDI-TOF-MS T2 - Organosilicon chemistry IV KW - Silsesquioxanes KW - NP-HPLC KW - LAC KW - SEC KW - MALDI-TOF-MS PY - 2000 SN - 3-527-29854-1 SP - 545 ff. PB - Wiley-VCH CY - Weinheim AN - OPUS4-2187 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Janiak, Ch. A1 - Lange, K.C.H. A1 - Marquardt, P. A1 - Krüger, Ralph-Peter A1 - Hanselmann, R. ED - Sun, J. ED - Janiak, C. T1 - Propene and 1-hexene oligomerization with unbridged alkyl-substituted cyclopentadienyl- and phospholyl-zirconium/MAO catalysts - mechanistic implications from oligomer analyses by NMR, SEC, and MALDI-TOF MS T2 - Advances on organometallic catalysts and olefin polymerization in China and Germany PY - 2001 SP - 117 EP - 142 PB - Chemical Industry Press CY - Bejing AN - OPUS4-2193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter ED - Jutzi, P. ED - Schubert, U. T1 - Characterization of Si-polymers by coupling of HPLC-separation methods with MALDI-TOF-MS T2 - Silicon chemistry : from the atom to extended systems T2 - Symposium on Silicon Chemistry CY - Werfenweng, Österreich DA - 2002-01-01 PY - 2003 SN - 3-527-30647-1 SP - 406 EP - 418 PB - Wiley-VCH CY - Weinheim AN - OPUS4-2194 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Polymer Characterization by Two-Dimensional HPLC and MALDI-TOF-MS T2 - 7th International Symposium on Polymer Analysis and Characterization (International journal of polymer analysis and characterization 1.1995,4 - 2.1996,3) T2 - 7th International Symposium on Polymer Analysis and Characterization (ISPAC) CY - Les Diablerets, Switzerland DA - 1994-05-24 PY - 1994 PB - Gordon and Breach CY - St. Helier, Jersey AN - OPUS4-2196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sonnenschein, Helmut A1 - Kreher, Th. A1 - Krüger, Ralph-Peter A1 - Ahlers, B. T1 - Synthesis of brigded indolizines-starting materials for molecular tweezers T2 - XVI th European Colloquium on Heterocyclic Chemistry T2 - XVI th European Colloquium on Heterocyclic Chemistry CY - Bled, Slovenia DA - 1994-09-25 PY - 1994 CY - Bled, Slovenia AN - OPUS4-2198 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Paulus, G. A1 - Resch, M. A1 - Schulz, Günter ED - Darms, R. ED - Suter, U. T1 - Polymer Characterization by MALDI-TOF-MS and Combination with HPLC T2 - 5th European Polymer Federation Symposium on Polymeric Materials (Macromolecular symposia 100) T2 - 5th European Polymer Federation Symposium on Polymeric Materials (EPF) CY - Basel, Switzerland DA - 1994-10-09 PY - 1994 SN - 3-85739-297-5 SN - 0258-0322 VL - 5 PB - Hüthig & Wepf CY - Zug AN - OPUS4-2200 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Maier, Bärbel A1 - Much, Helmut A1 - Schulz, Günter T1 - Orthogonal two-dimensional chromatography of poly(ethylene oxid) adducts T2 - Proceedings of HPLC '96 T2 - HPLC '96 CY - San Francisco, CA, USA DA - 1996-06-16 PY - 1996 CY - San Francisco AN - OPUS4-2221 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter A1 - Frey, H. T1 - Characterization of unusual Silsesquioxane-Based Polymer Architectures Based on the Coupling of Liquid Chromatography and MALDI-TOF-MS T2 - 11th International Symposium on Organosilicon Chemistry T2 - 11th International Symposium on Organosilicon Chemistry CY - Montpellier, France DA - 1996-09-01 PY - 1996 CY - Montpellier AN - OPUS4-2222 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Much, Helmut A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter ED - Berger, T. T1 - New methods for characterization of polymer heterogeneity by combination of HPLC with MALDI-TOF-MS T2 - 21st International Symposium on Chromatography (Chromatographia 45) T2 - 21st International Symposium on Chromatography CY - Stuttgart, Germany DA - 1996-09-15 PY - 1996 SN - 0009-5893 IS - 45 PB - Vieweg CY - Wiesbaden AN - OPUS4-2223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, A. A1 - Krüger, Ralph-Peter T1 - Quantitative analysis of molecular weight distribution obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry T2 - Tagungsband der DECHEMA-Diskussionstagung "Neue Methoden der Polymeranalytik" T2 - DECHEMA-Diskussionstagung "Neue Methoden der Polymeranalytik" CY - Mainz, Germany DA - 1996-10-07 PY - 1996 CY - Mainz AN - OPUS4-2224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Pickard, M. A1 - Schulz, Günter A1 - Wachsen, O. T1 - Characterization of thermal and hydrolytic degradation of polylactides by Liquid Chromatography and MALDI-TOF mass spectrometry T2 - Hamburger Makromolekulares Symposium T2 - International Symposium on "Biodegradable Materials" and Hamburger Makromolekulares Symposium CY - Hamburg, Germany DA - 1996-10-07 PY - 1996 CY - Hamburg AN - OPUS4-2225 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter ED - Fell, A. T1 - Two-dimensional chromatography, their optimization and coupling with different detection techniques for investigation of polymer heterogeneity T2 - 21st International Symposium on High Performance Liquid Phase Separations and Related Techniques (Journal of chromatography : A) T2 - 21st International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC) CY - Birmingham, England, UK DA - 1997-06-22 PY - 1997 SN - 0021-9673 PB - Elsevier CY - Amsterdam AN - OPUS4-2232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Coupling of different modes of liquid chromatography of polymers with spectroscopic methods and MALDI-TOF-MS-key for determination of polymer heterogeneity T2 - Proceedings of the 6th SPSJ International Polymer Conference T2 - 6th SPSJ International Polymer Conference (IPC 97) CY - Kusatsu, Japan DA - 1997-10-20 PY - 1997 VL - 6 AN - OPUS4-2233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rikowski, E. A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Synthesis of Polyhedral Hexa-, Octa-, Deca- and Dodeca Silsesquioxanes, Separation by NP-HPLC, SEC and LACCC, Characterization by MALDI-TOF-MS T2 - Tagungsband der 4. Münchener Silikontage T2 - 4. Münchener Silikontage CY - München, Germany DA - 1998-04-07 PY - 1998 VL - 4 AN - OPUS4-2234 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter A1 - Rikowski, E. T1 - Characterization of silicon polymers (silsesquioxanes, dendrimers and copolymers) by means of different modes of Liquid Chromatography and MALDI-TOF-MS T2 - Analytica Conference PY - 1998 PB - Messe München GmbH CY - München AN - OPUS4-2236 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Schulz, Günter T1 - Characterization of silicon polymers by means of different liquid chromatographic modes and MALDI-TOF-MS T2 - DFG-Symposium zum Schwerpunktprogramm "Silicium-Chemie" T2 - DFG-Symposium zum Schwerpunktprogramm "Silicium-Chemie" CY - Werfenweng, Austria DA - 1998-06-11 PY - 1998 AN - OPUS4-2237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Investigations of Polymer Heterogeneity by Two-Dimensional HPLC, MALDI-TOF-MS and FTIR Coupling T2 - 8th International Symposium on Polymer Analysis and Characterization T2 - ISPAC 8, HPLC ´95 CY - Sanibel Island, FL, USA DA - 1995-05-20 PY - 1995 PB - Gordon and Breach CY - Sant Helier AN - OPUS4-2203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Much, Helmut A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Investigation of Macromer Heterogeneity by Two-Dimensional HPLC and MALDI-TOF-MS T2 - Proceedings of the 19th International Symposium on Column Liquid Chromatography and Related Techniques T2 - 19th International Symposium on Column Liquid Chromatography CY - Innsbruck, Austria DA - 1995-05-28 PY - 1995 CY - Innsbruck AN - OPUS4-2204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maier, B. A1 - Trathnigg, B. A1 - Much, Helmut A1 - Krüger, Ralph-Peter A1 - Berek, D. T1 - Characterization of polyethers using different chromatographic techniques and MALDI-TOF-MS T2 - Proceedings of the 19th International Symposium on Column Liquid Chromatography and Related Techniques PY - 1995 CY - Innsbruck AN - OPUS4-2205 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Investigation of Macromer Heterogeneity by 2D-HPLC and MALDI-TOF-MS T2 - Bericht der Präsentationsveranstaltung des Instituts für Angewandte Chemie Berlin-Adlershof e.V. T2 - Präsentationsveranstaltung des Instituts für Angewandte Chemie Berlin-Adlershof e.V. CY - Berlin, Germany DA - 1995-09-26 PY - 1995 CY - Berlin AN - OPUS4-2207 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Ralph-Peter A1 - Kricheldorf, H.R. A1 - Böhme, S. T1 - Macrocycles 16. Macrocyclic Dibutyltin Dicarboxylates by Ring-Closing Polycondensation JF - Macromolecular chemistry and physics N2 - Various dibutyltin derivatives were polycondensed with aliphatic ,-dicarboxylic acids having chain lengths from 4 (succinic acid) to 22 carbon atoms. White crystalline products were obtained from all experiments, and the structure of the products was independent of the synthetic method. Viscosity measurements revealed low molecular weights (n 1 500 Da) in all cases. Vapor pressure osmometry (VPO) measurements and matrix-assisted laser desorption time-of-flight (MALDI-TOF) mass spectrometry proved that cyclic dimers and trimer were formed from dicarboxylic acids having 6 to 16 carbons, but mainly the monomeric cycle from docosane dioic acid. Heating to 250°C did not change the structure. Therefore, the results indicate that the macrocycles are the result of a thermodynamically controlled ring-closing polycondensation. This means that linear high-molecular weight poly(dibutyltin dicarboxylate)s cannot exist above room temperature. PY - 2002 DO - https://doi.org/10.1002/1521-3935(20020101)203:2<313::AID-MACP313>3.0.CO;2-V SN - 1022-1352 SN - 1521-3935 VL - 203 IS - 2 SP - 313 EP - 318 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-1796 LA - eng 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" 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 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter T1 - Characterization of polylactides by coupling of chromatographic methods with MALDI-TOF-MS T2 - Polydays 2002 T2 - Polydays 2002 ; ISPAC 2002 CY - Berlin, Germany DA - 2002-09-30 PY - 2002 AN - OPUS4-1807 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grimm, B. A1 - Krüger, Ralph-Peter A1 - Schrader, S. A1 - Prescher, D. T1 - Molecular structure investigations on fluorine-containing polyazomethines by means of MALDI-TOF-MS technique T2 - Berliner Polymeren-Tage T2 - Berliner Polymerentage 2000 CY - Berlin, Germany DA - 2000-10-09 PY - 2000 CY - Berlin AN - OPUS4-2253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -