In this report, poly(ethylene glycol) (PEG) was quantitatively removed from commercial monomethyl ethers of PEG (MPEG) by column chromatography on silica gel on a preparative scale. Most of commercial MPEG, with molecular weights as high as 5000, and containing only up to 20% of PEG, were effectively purified by this technique. The content of PEG in MPEG obtained is comparable or even lower than that in samples of MPEG prepared by anionic polymerization of ethylene oxide under strictly controlled conditions. An analytical approach combining H¹ NMR and chromatography techniques indicates that the PEG content in the chromatographically purified MPEG samples is less than 1%.

The synthesis of high-molar-mass linear and 6-arm star-shaped poly(l-lactide)s(PLLA’s) is presented. Dipentaerythritol and benzyl alcohol were used asinitiators and Sn(Oct)2 was applied asa catalyst in the ring-opening polymerization (ROP) of l-lactide (l-LA) carried out at 130 °C. The prepared PLLA’s were characterized by SEC (size exclusion chromatography), 1H NMR (proton nuclear magnetic resonance spectroscopy), DSC (differential scanning calorimetry), and TGA (thermogravimetric analysis). The structure of the obtained star-shaped polymers was confirmed by comparison of the radii of gyration (Rg) determined by SEC for the linear and star macromolecules. The thermal properties of PLLA’s were shown for the wide range of molar masses. Additionally, it was confirmed that Irganox stabilizer has an influence on the thermal stability of PLLA’s.