Recyclable, Reprocessable, Anticorrosive, and Hydrolysis-Resistant Long-Chain Aliphatic Polycarbonates as Polyethylene-like Materials

Disposable plastic items (packages in particular) cause serious resource waste and environmental pollution. Alternative materials resembling macroscopic properties of traditional plastics while possessing degradability and recyclability are anticipated to address such global challenges. Herein, we presented facile synthesis of long-chain aliphatic polycarbonates via fluoride-promoted carbonylation polymerization by using 1,1 '-carbonyldiimidazole and cesium fluoride as the activator and catalyst, respectively. This mild preparation process circumvents several deficiencies owned by conventional polycondensation for polycarbonate synthesis, such as manipulation of corrosive/toxic reagents, high energy consumption, and time cost. The as-prepared polycarbonates showed high molecular weights and good thermal stabilities. Key thermal parameters such as crystallization/melting temperatures and enthalpies were positively associated with the methylene spacer lengths of the repeating units of these polymers. In particular, a plausible odd-even effect was observed from the wide-angle X-ray diffraction patterns of these specimens. These polyethylene-like materials virtually bridged the gap between polycondensates and polyolefins in that these samples displayed comparable crystal morphology, film-forming property, reprocessability, surface wettability, hydrolysis resistance, and anticorrosiveness to high-density polyethylene. Meanwhile, these polyethylene mimics manifested remarkable recyclability through alkaline hydrolysis upon heating in that almost complete recovery (>96%) of aliphatic diol was achieved for each case. On the other hand, inorganic fillers, including toner, phosphor, magnetite, and silver powders and micro/nanoparticles were homogeneously dispersed in these polycarbonate matrices via vortex mixing to create colored, phosphorescent, magnetic, and conductive composite films, respectively.