Heléne Magnusson

Synthesis of hyperbranched aliphatic polyethers via cationic ring-opening polymerization of 3-ethyl-3-(hydroxymethyl)oxetane

Thermally initiated cationic ring-opening polymerization of 3-ethyl-3-(hydroxymethyl)oxetane was carried out using benzyltetramethylenesulfonium hexafluoroantimonate as initiator. The resulting hydroxy-functional polyether was thoroughly analyzed by 1H and 13C NMR spectroscopy and found to have a hyperbranched architecture with a degree of branching of 0.4. The polyether was successfully employed as a multifunctional initiator for e-caprolactone. Molecular weight measurements on the polyether showed a narrow molecular weight distribution analyzed by SEC and MALDI-TOF (1.3 and 1.4, respectively).

The effect of degree of branching on the rheological and thermal properties of hyperbranched aliphatic polyethers

A series of hyperbranched aliphatic polyethers with different degree of branching (DB) and molecular weights have been studied with respect to their rheological and thermal properties. The DB was shown to affect the ability of the polymers to crystallize and thereby also the rheological properties of the polymers. A low DB resulted in semi-crystalline polymers with melting points between 100 and 130°C. The polymers with a higher DB were essentially amorphous and behaved as non-entangled Newtonian liquids in the molten state.

Insights into ToF-SIMS analysis of dendritic macromolecules: cationization and PCA to probe their molecular weight on surfaces

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is utilized to study dendrons, dendrimers and hyperbranched derivatives prepared from the 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) or ...