Crystallization Behavior of Spray-Dried and Freeze-Dried Graphene Oxide/Poly(trimethylene terephthalate) Composites

Two types of graphene oxide (GO) powders were prepared by freeze-drying or spray-drying method, and their composites with poly(trimethylene terephthalate) (PTT) were prepared by melt blending. The influence of GO powders' type and content on crystallization behavior of PTT was investigated by differential scanning calorimeter (DSC) and polarized optical microscopy (POM). DSC results indicated that the overall crystallization rate of PTT was accelerated by well-dispersed GO material which acts as a heterogeneous nucleation agent, since the Avrami parameter obtained is near 3. On the contrary, large GO aggregates which is in the minority will hinder the nucleation. Interestingly, large and well-defined PTT spherulites instead of tremendous stunted spherulites were observed from POM, which means only a small portion of GO powders was acted as nucleation agent. Meanwhile, GO powders had no effect on PTT spherulites growth rate. In addition, the band spacing of PTT spherulites became weaker and wider with increasing GO content. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40332.