High Thermal Stability of Bio-Based Polycarbonates Containing Cyclic Ketal Moieties

Bio-based polycarbonates containing cyclic ketal moieties were designed, and the bio-based diol monomer was synthesized by CQ with glycerol to improve their thermal properties and replace BPA in polymer industry. The molecular structure of the novel bio-based diol monomer 2,2:3,3-bis(4'-hydroxymethylethylenedioxy)-1,7,7-trimethylbicyclo[2.2.1]heptane (abbreviated as CaG) was analyzed by H-1, C-13, and 2D-COSY NMR techniques. GPC results show that CaG was reacted successfully and led to the high molecular weights for homopolycarbonate (M-w = 18 652) abbreviated as PCaGC and for copolycarbonate (M-w = 78 482) as PCaG(20)BPA(80)C. The high thermal stability (T-d value above 350 degrees C) and glass transition temperature (T-g value from 128 to 151 degrees C) of PCaGCs and PCaG(x)BPA(y)Cs were studied by TGA and DSC, respectively. Given the sufficient reactivity and high thermal stability, CaG is a promising renewable building block for applicable polymers.