Filtern
Erscheinungsjahr
Dokumenttyp
- Zeitschriftenartikel (23) (entfernen)
Sprache
- Englisch (23)
Schlagworte
- MALDI (5)
- MALDI-TOF MS (5)
- Polylactide (4)
- Polymere (4)
- Amphiphiles (2)
- Block copolymers (2)
- Chromatographie (2)
- Imaging (2)
- Kopplung (2)
- Liquid chromatography (2)
- MALDI-TOF mass spectrometry (2)
- MS/MS (2)
- Mass spectrometry (2)
- Polycondensation (2)
- Reversible addition fragmentation chain transfer (RAFT) (2)
- Artificial weathering (1)
- Biodegradable (1)
- Biopolymers (1)
- Catalysts (1)
- Chromatography (1)
- Copolymer composition (1)
- Copolymeranalytik (1)
- Coupling (1)
- Coupling methods (1)
- Crosslinking (1)
- Crystalinity (1)
- Crystallization (1)
- Degradation (1)
- ESI (1)
- ESI-Massenspektrometrie (1)
- Electrospray ionization (1)
- Europium (1)
- FTIR (1)
- Fragmentierung (1)
- Ft-IR (1)
- Gradient chromatography (1)
- Gradient elution (1)
- Gradient elution liquid chromatography (GELC) (1)
- Hydrolytic degradation (1)
- Hyphenated techniques (1)
- Inductively coupled plasma-mass spectrometry (1)
- Ionization mass spectrometry (1)
- Kopplungsmethoden (1)
- LC-MS coupling (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 Massenspektrometrie (1)
- MALDI TOF Massenspektrometrie (1)
- MALDI-TOF-MS (1)
- Massenspektrometrie (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 of polymerization (1)
- Moisture (1)
- N-vinyl pyrrolidone (1)
- Poly(ethylene glycol) (1)
- Polycarbonate-co-dimethylsiloxane copolymer (1)
- Polymerization mechanisms (1)
- Polyurethane (1)
- Reversible addition/fragmentation chain transfer (RAFT) (1)
- Ring opening polymerization (ROP) (1)
- SAXS (1)
- SEC (1)
- Size-exclusion chromatography (1)
- Soft ionization mass spectrometry (ESI, MALDI) (1)
- Software (1)
- Two-dimensional-liquid chromatography (2D-LC) (1)
- UPLC (1)
Organisationseinheit der BAM
- 6 Materialchemie (6)
- 6.3 Strukturanalytik (6)
- 1 Analytische Chemie; Referenzmaterialien (1)
- 1.2 Biophotonik (1)
- 1.7 Organische Spuren- und Lebensmittelanalytik (1)
- 5 Werkstofftechnik (1)
- 5.6 Glas (1)
- 6.6 Physik und chemische Analytik der Polymere (1)
- 7 Bauwerkssicherheit (1)
- 7.5 Technische Eigenschaften von Polymerwerkstoffen (1)
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.
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.
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.