Filtern
Erscheinungsjahr
Dokumenttyp
- Zeitschriftenartikel (168)
Referierte Publikation
- ja (168) (entfernen)
Schlagworte
- MALDI-TOF MS (55)
- Polylactide (40)
- Cyclization (26)
- MALDI (16)
- Polycondensation (15)
- Ring-opening polymerization (15)
- Polymerization (8)
- MALDI TOF MS (7)
- Crystallization (6)
- Pollen (6)
- Ring-expansion polymerization (6)
- Transesterification (6)
- Catalyst (5)
- Crystalinity (5)
- Isosorbide (5)
- Lactide (5)
- Mass spectrometry (5)
- Polyester (5)
- Polymere (5)
- Polymers (5)
- Catalysts (4)
- Ionization (4)
- MALDI Massenspektrometrie (4)
- MALDI-TOF mass spectrometry (4)
- Polyesters (4)
- Bismuth (3)
- Imaging (3)
- Liquid chromatography (3)
- Polylactides (3)
- ROPPOC (3)
- Ring opening polymerization (3)
- SEC (3)
- Small-angle X-ray scattering (3)
- Adsorption (2)
- Amphiphiles (2)
- Biobased polymers (2)
- Biodegradable (2)
- Blends (2)
- Block copolymers (2)
- Catechol (2)
- Chromatographie (2)
- Coupling methods (2)
- Crosslinking (2)
- Crystals (2)
- Cyclic (2)
- Cyclopolymerization (2)
- Dispersity (2)
- Epsilon-caprolactone (2)
- FTIR (2)
- Field-flow fractionation (2)
- ICP-MS (2)
- Kopplung (2)
- MALDI mass spectrometry (2)
- MALDI-TOF-MS (2)
- MS/MS (2)
- Macrocycles (2)
- Massenspektrometrie (2)
- Multivariate statistics (2)
- Polyglycolide (2)
- Polymer (2)
- Polymerisation (2)
- Polystyrene (2)
- Polyurethane (2)
- Polyurethanes (2)
- Reversible addition fragmentation chain transfer (RAFT) (2)
- Ring-opening Polymerization (2)
- SAXS (2)
- Sample preparation (2)
- Silver nanoparticles (2)
- Synthesis (2)
- Thermal degradation (2)
- Tin catalysts (2)
- 2-oxazoline (1)
- A4F (1)
- AET (1)
- AFM (1)
- Adhesion promotion (1)
- Alternating co-poly(ether pyridine)s (1)
- Amphiphilic polymers (1)
- Annealing (1)
- Application (1)
- Aromatic organic compounds, (1)
- Aromatic pollutants (1)
- Artificial weathering (1)
- Aryl iodides (1)
- Asymmetric flow filed-flow fractionation (1)
- Asymmetrical flow field flow fractionation (AF4) (1)
- Attenuated total reflectance-Fourier transorm infrared spectroscopy (1)
- Biodegradability (1)
- Biodegradable polyesters (1)
- Biopolymers (1)
- Biosourced isosorbide (1)
- Blockcopolymer (1)
- CRM (1)
- Caco-2 cells (1)
- Caesium (1)
- Capillary electrophoresis (1)
- Capillary electrophoresis (CE) (1)
- Carbon fiberepoxy resin laminates (1)
- Carboxyl group (1)
- Catalytic ability (1)
- Cationic ring opening polymerization (1)
- Cationization (1)
- Chain scission (1)
- Chemical reduction of functional groups (1)
- Chromatography (1)
- Classification (1)
- Click chemistry (1)
- Conductive carbon tape (1)
- Conjugated oligomers (1)
- Controlled radical polymerization (1)
- Conversion (1)
- Copolyester (1)
- Copolymer composition (1)
- Copolymer sequence (1)
- Copolymeranalytik (1)
- Copolymerization (1)
- Cotton effect (1)
- Coupling (1)
- Cyclics (1)
- Cyclisation (1)
- Cycloaddition (1)
- Cycloparaphenylenes (1)
- DCTB (1)
- Degradation (1)
- Dendrimers (1)
- Dendrons (1)
- Dried droplet (1)
- Droplet (1)
- Dynamic light scattering (1)
- ESI (1)
- ESI-Massenspektrometrie (1)
- Electron paramagnetic resonance study (1)
- Electrospray (1)
- Electrospray ionization (1)
- Electrospray ionization (ESI) (1)
- Epsilon-Caprolactone (1)
- Epsilon-caprolactone (e-CL) (1)
- Europium (1)
- Foldamers (1)
- Fractionation of polymers (1)
- Fragmentierung (1)
- Friction (1)
- Ft-IR (1)
- Functionalized graphene nanoribbons (1)
- Fundamentals (1)
- Glycodendrimers (1)
- Glycolide (1)
- Gradient chromatography (1)
- Gradient elution (1)
- Gradient elution liquid chromatography (GELC) (1)
- Graphene monomers (1)
- Graphene nanoribbons (1)
- Graphene wires (1)
- Green chemistry (1)
- Hafnium (1)
- Heavy metals (1)
- Hexabenzocoronene (1)
- Hierarchical cluster analysis (1)
- Hierarchical self-assembly (1)
- High performance liquid chromatography (1)
- Host–guest systems (1)
- Humidity (1)
- Hybrid nanoparticles (1)
- Hydrolytic degradation (1)
- Hyphenated techniques (1)
- Imaging MS (1)
- In situ EXAFS (1)
- In situ SAXS/WAXS (1)
- In vitro digestion (1)
- Inductively coupled plasma-mass spectrometry (1)
- Inlet ionization (1)
- Intrinsic viscosity (1)
- Ion mobility (1)
- Ionization mass spectrometry (1)
- Iron oxide nanoparticles (1)
- Irreversible polycondensation (1)
- Isophthalic acid (1)
- Isotope dilution analysis (1)
- Jacobsen-Stockmayer theory (1)
- Kopplungsmethoden (1)
- L-lactide (1)
- LC-MS coupling (1)
- Lactides (1)
- Lacunary Keggin ion (1)
- Lanthanide ions (1)
- Laser-induced redox reactions (1)
- Layer topography (1)
- Lead ions (1)
- Light scattering (LS) (1)
- Liquid adsorption chromatography (1)
- Liquid adsorption chromatography at critical conditions (1)
- Liquid chromatography at critical conditions (1)
- Liquid chromatography under critical conditions (LCCC) (1)
- MALDI Imaging MS (1)
- MALDI TOF Massenspektrometrie (1)
- MALDI TOF mass spectrometry (1)
- MALDI-TOF (1)
- MALDI-TOF MS/MS (1)
- MOF (1)
- Mass Spectrometry (1)
- Mass spectrometry imaging (1)
- Materials Chemistry (1)
- Matrices (1)
- Matrix segregation (1)
- Matrix-assisted ionization ion mobility spectrometry mass spectrometry (1)
- Matrix-assisted laser desorption (1)
- Matrix-assisted laser desorption/ionization (1)
- Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) (1)
- Matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (1)
- Mechanism (1)
- Mechanism of polymerization (1)
- Mega-dalton (1)
- Metal ion complexation (1)
- Metal ion-intradendrimer complexes (1)
- Metal triflates (1)
- Microwave (1)
- Moisture (1)
- Molar mass determination (1)
- Molar mass distribution (1)
- Molecular masses (1)
- Molecular recognition (1)
- Morphology (1)
- Multicyclic polymers (1)
- Multivariate Statistics (1)
- Multivariate analyses (1)
- N-vinyl pyrrolidone (1)
- Nanolithography (1)
- Nanoparticle (1)
- Nanoparticles (1)
- Nanoparticles with same nominal diameter (1)
- Networks (1)
- Oligoazobenzene (1)
- Oligospiroketals (1)
- On-surface polymerization (1)
- Organic Chemistry (1)
- PCA (1)
- PET (1)
- Partial least square discriminant analysis (PLS-DA) (1)
- Pentafluoropyridine (1)
- Phenolic acid (1)
- Phenolic compounds (1)
- Phenyleneethynylenes (1)
- Phosphonate esters (1)
- Photoligation (1)
- Photooxidation (1)
- Photoswitchable (1)
- Plasma (1)
- Plasma modification (1)
- Pollen grains (1)
- Poly(ether-phosphoramide)s sulfides (1)
- Poly(ethylene glycol) (1)
- Poly(ethylene terephthalate) (1)
- Polyaddition (1)
- Polycaprolactone (1)
- Polycarbonate-co-dimethylsiloxane copolymer (1)
- Polycondensations (1)
- Polyelectrolytes (1)
- Polyethylene oxide (1)
- Polyforamidine (1)
- Polykondensation (1)
- Polymer MALDI (1)
- Polymer blends (1)
- Polymer film (1)
- Polymer reference materials (1)
- Polymerization mechanisms (1)
- Polymers and Plastics (1)
- Polyoxometalates (1)
- Polysarcosine (1)
- Principal component analysis (1)
- Principal component analysis (PCA) (1)
- Quantification (1)
- ROMP (1)
- Raman (1)
- Renewable resources (1)
- Reversible addition/fragmentation chain transfer (RAFT) (1)
- Ring opening polymerization (ROP) (1)
- Ring-opening Polymerisation (1)
- Ring-opening polymerizations (1)
- Salicylate (1)
- Sample loss (1)
- Sample pretreatment (1)
- Self-assembly (1)
- Semi-interpenetrating networks (1)
- Silica gel modification (1)
- Size exclusion chromatography (1)
- Size exclusion chromatography (SEC) (1)
- Size-exclusion chromatography (1)
- Sn catalysts (1)
- Soft ionization mass spectrometry (ESI, MALDI) (1)
- Software (1)
- Solvent-free (1)
- Sonoga (1)
- Sorption isotherm (1)
- Sorption mechanism (1)
- Speciation (1)
- Spirocyclic (1)
- Stereocomplex (1)
- Succinic acid (1)
- Sulfobetaines (1)
- Supramolecular chemistry (1)
- Surface coating (1)
- TPU (1)
- Target plate material (1)
- Telechelic polyesters (1)
- Thermo-desorption (1)
- Thermochemistry (1)
- Thin polymer layers (1)
- Tin acetates (1)
- Tin(II)octanoate (1)
- Toxicity (1)
- Triazenes (1)
- Two-dimensional off-line coupling (1)
- Two-dimensional-liquid chromatography (2D-LC) (1)
- UPLC (1)
- UV degradation (1)
- UV radiation (1)
- Ultraschallfalle (1)
- Universal calibration (1)
- Vacuum ionization (1)
- Water-soluble polymers (1)
- X-ray photoelectron spectroscopy (1)
- Zinc catalyst (1)
- a2 + b3 polycondensation (1)
- cyclization (1)
- dispersity (1)
- mass spectra (1)
- mass spectrometry (1)
- polycondensation (1)
- polyesters (1)
- polyionic liquids (1)
- reversible addition fragmentation chain transfer (RAFT) polymerization (1)
- ring-expansion polymerization (1)
- surface modification (1)
Organisationseinheit der BAM
- 6 Materialchemie (73)
- 6.3 Strukturanalytik (73)
- 1 Analytische Chemie; Referenzmaterialien (5)
- 1.2 Biophotonik (2)
- 1.7 Organische Spuren- und Lebensmittelanalytik (2)
- 6.6 Physik und chemische Analytik der Polymere (2)
- 7 Bauwerkssicherheit (2)
- 7.5 Technische Eigenschaften von Polymerwerkstoffen (2)
- 1.0 Abteilungsleitung und andere (1)
- 1.3 Instrumentelle Analytik (1)
The polycondensations of adipic acid and 1,10-decanediol catalyzed by toluene sulfonic acid (TSA) were reinvestigated using MALDI TOF mass spectrometry and NMR spectroscopy. Unexpected reactions of TSA were detected along with incomplete conversion of the monomers. Furthermore, transesterification reactions of end-capped poly(1,10-decanediol adipate) and end-capped poly(ε-caprolactone) catalyzed by TSA were studied. Despite the quite different (ionic) reaction mechanisms, it was found that for polycondensations performed in bulk intermolecular transesterification is more efficient than the intramolecular “back-biting”; this scenario was not considered in the Jacobson–Stockmayer theory of reversible polycondensations.
These results also confirm that the Jacobson–Stockmayer explanation of reversible polycondensations solely on the basis of ring chain equilibration is not only devoid of any experimental evidence, but also in contradiction to the results elaborated in this work.
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.
PVP-block-PVAc block copolymers were synthesized by controlled radical polymerization applying a RAFT/MADIX system and were investigated by HPLC and by coupling of chromatography to FT-IR spectroscopy and MALDI-TOF MS. Chromatographic methods (LACCC and gradient techniques) were developed that allowed a separation of block copolymers according to their repeating units. The results of the spectroscopic and spectrometric analysis clearly showed transfer between radicals and process solvent. With the use of hyphenated techniques differences between main and side products were detected. In agreement with previously published results, obtained by NMR, SEC, static light scattering and MALDI-TOF MS, our data proved a non-ideal RAFT polymerization.
The results of copolymer characterization by coupling of chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) techniques and subsequent calculation of copolymer composition using a novel software tool MassChrom2D are presented. For high-resolution mass analysis copolymer samples were fractionated by means of liquid adsorption chromatography (LAC). These fractions were investigated off-line by MALDI-TOF MS. Various mono-n-butyl ethers of polyethylene oxide-polypropylene oxide copolymers (PEO-co-PPO) were investigated. As well as the copolymer composition presented in two-dimensional plots, the applied approach can give additional hints on specific structure-dependent separation conditions in chromatography.
Sequences and end groups of complex copolyesters were determined by fragmentation analysis by means of matrix-assisted laser desorption/ionization collision-induced dissociation tandem mass spectrometry (MALDI CID MS/MS). The complexity of the crude copolyester mixture was reduced by a chromatographic separation followed by a MALDI time-of-flight (TOF) investigation of fractions. Due to overlapping compositional and end-group information a clear assignment of end groups was very difficult. However, the fragmentation of suitable precursor ions resulted in typical fragment ion patterns and, therefore, enabled a fast and unambiguous determination of the end groups and composition of this important class of polymers.
New amphiphilic block copolymers consisting of N-vinyl pyrrolidone and vinyl acetate were synthesized via controlled radical polymerization using a reversible addition/fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) system. The synthesis was carried out in 1,4-dioxane as process solvent. In order to get conclusions on the mechanism of the polymerization the molecular structure of formed copolymers was analysed by means of different analytical techniques. 13C NMR spectroscopy was used for the determination of the monomer ratios. End groups were analysed by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This technique was also used to determine possible fragmentations of the RAFT end groups. By means of a combination of size exclusion chromatography, 13C NMR and static light scattering molar mass distributions and absolute molar masses could be analysed. The results clearly show a non-ideal RAFT mechanism.
Two decades after the introduction of matrix assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI), soft ionization mass spectrometry represents a powerful toolset for the structural investigation of synthetic polymers. The present review highlights the current state-of-the-art, covering the latest developments of novel techniques, enabling instrumentation as well as the important applications of soft ionization MS from the beginning of 2008. Special attention is paid to the role that soft ionization MS has played in the mechanistic investigation of radical polymerization processes since 2005.
The adhesion of poly(methyl methacrylate) (PMMA) and polystyrene (PS) films, whose surface has been previously structured by dynamic plowing lithography (DPL), has been measured by means of forcedisplacement curves. The different adhesion of modified and unmodified PS leads to the assumption that polymer chains are broken during DPL. After measuring the energy dissipated by the tip during DPL, in order to check that the transferred energy is sufficient to break covalent bonds, the polymer chain scission caused by the lithographic process has been definitely confirmed by size exclusion chromatography measurements of the lithographed films.