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.magnified image

Summary: The structure of polyacetal copolymers with respect to their end groups is investigated. Several techniques, such as liquid chromatography, MALDI‐TOF MS, IR and NMR spectroscopy, as well as combined techniques like 2D chromatography have been applied. Cyclic oligomers and polymers with formyl, hydroxy, and aliphatic end groups are identified. 2D chromatography shows that all the separated species are homogenously distributed with respect to their molar mass.2D chromatograms of sample F97B3.magnified image2D chromatograms of sample F97B3.