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 <sup>1</sup>H, <sup>13</sup>C, and 2D-COSY NMR techniques. GPC results show that CaG was reacted successfully and led to the high molecular weights for homopolycarbonate (<i>M</i><sub>w</sub> = 18 652) abbreviated as PCaGC and for copolycarbonate (<i>M</i><sub>w</sub> = 78 482) as PCaG<sub>20</sub>BPA<sub>80</sub>C. The high thermal stability (<i>T</i><sub>d</sub> value above 350 °C) and glass transition temperature (<i>T</i><sub>g</sub> value from 128 to 151 °C) of PCaGCs and PCaG<sub><i>x</i></sub>BPA<sub><i>y</i></sub>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.