A simple and efficient method for the synthesis of lactose-based homopolymers from N-lactosyl-N′-(4-vinylbenzyl)urea or N′-lactosyl-N,N-methyl(4-vinylbenzyl)urea (5a, 5b) is described. Free radical polymerization of these new urea monomers proceeded smoothly in an aqueous solution using potassium persulfate (KPS) and N,N,N′,N′-tetramethylethylenediamine (TMEDA) as the initiating system and gave water-soluble homopolymers in good yields. These synthetic lactose-based polymers had molecular weights that ranged from 1.9 × 103 to 5.3 × 106 and low molecular weight polydispersities (Mw/Mn) (1.02-1.77) as determined by gel permeation chromatography (GPC). Thermal stability studies showed that these homopolymers had two-stage degradations related to the lactose moiety and the polystyrene main chain as well as similar Tg's (6a at 134°C, 6b at 133°C) as determined by DSC, suggesting that the urea linkage increases the Tg by hydrogen bonding. The present synthetic method is useful for the introduction of biologically important amino sugars into glycopolymers through a urea linkage.
ASJC Scopus subject areas
- Materials Chemistry