Preparation of Macrodiols and Polyols by Chopping High-Molecular-Weight Aliphatic Polycarbonates

High-molecular-weight poly(1,4-butylene carbonate) (PBC) (M-n: 40,000-90,000) was prepared through the condensation polymerization of dimethyl carbonate (DMC) and 1,4-butanediol (BD) in the presence of 0.05 mol % sodium alkoxide catalyst. The subsequent feeding of 15 mol % HOAOH, such as 1,6-hexanediol, 1,5-pentanediol, 1,4-cyclohexanedimethanol, or 1,4-benzenedimethanol and stirring at 190-150 degrees C converted the extremely thick high-molecular-weight polymer to low-molecular-weight macrodiols with GPC-measured M-n approximate to 2000. The analysis of the H-1 NMR spectra indicated that the -A- units and 1,4-butylene units were randomly distributed in the resulting oligomers. The chopping of the high-molecular-weight PBC using either triols or tetraols such as glycerol propoxylate, 1,1,1-tris(hydroxymethyl)ethane, or pentaerythritol also afforded macropolyols containing branched chains with GPC-measured M-n approximate to 2000. When the chopped polymers were genuine PBCs, the resulting macrodiols or polyols were in a waxy state at room temperature. However, permanently oily compounds were obtained when the chopped polymers were prepared using 0.90 mole fraction of BD admixed with various other diols. The macrodiols and polyols synthesized in this study may have potential applications in the polyurethane industry. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1570-1580