Experimental studies on the ring opening polymerization of p-dioxanone using an Al((OPr)-Pr-i)(3)-monosaccharide initiator system

The ring opening polymerization (ROP) of p-dioxanone using a protected monosaccharide (1,2;3.4-di-O-isopropylidene-alpha-D-galactopyranose)/Al((OPr)-Pr-i)(3) initiator system to yield polydioxanone with a protected monosaccharide end-group is described. The products were synthesized at 60-100 degrees C and characterized by H-1 and C-13 NMR, and MALDI-TOF mass spectrometry. Besides the desired polydioxanone functionalised with a monosaccharide end-group, also polydioxanone with an (OPr)-Pr-i end-group was formed (20-30%). Systematic studies showed that the polymer yield is a function of the reaction temperature and the reaction time, with higher temperatures (100 degrees C) leading to lower yields. The average chain length of the polymers is between 7 and 58 repeating units and may be tuned by the monomer to monosaccharide ratio (at constant Al((OPr)-Pr-i)(3) intake). A statistical model has been developed that successfully describes the experimentally observed relation between the average chain length of the functionalized polymer and reaction parameters. (C) 2008 Elsevier Ltd. All rights reserved.