Synthesis and characterization of poly(glycolic acid) (PGA) and its graphene oxide hybrids (PGA-GO)

PGA and PGA-GO hybrids with relatively low graphene oxide (GO) concentrations (0.5–2.5 wt%) were mass synthesized. In the preparation of GO, a modified Hummer’s method was used, and both PGA and PGA-GO followed similar synthesis routes. After forming PGA-GO hybrids, it was demonstrated that the reaction products rendered higher molecular weights as the GO concentration increased. The calorimetric traces showed heterogeneous nucleation and dual crystallization and melting mechanisms, the PGA-GO hybrids having higher melting points than neat PGA. There were no changes in crystal habits in these products, although crystal perfection and crystal thickening depended on the GO concentration. Both effects were associated with the higher melting points of the PGA-GO hybrids. Thermo-gravimetric measurements showed increases in thermal stabilities up to 20% depending on the GO concentration. Isothermal mass crystallization indicated enhancement of crystallization rates and crystal geometry changes from spherical to cylindrical depending on the GO concentration. There were also small clusters and other entities involved in the crystallization process. Graphical abstract