Synthesis and Characterization of Graphite Nanomaterials

Cyclic butylene terephthalate oligomers [CBT100, Mw = (220)n g/mol, n = 2–7, melting point = 130 ÷ 160 °C] and butyltin chloride dihydroxide catalyst (96%, melting point 150 °C) were purchased from IQ-Holding Distributor of products previously commercialized by Cyclics Europe GmbH ((Schwarzheide, Germany) and Sigma-Aldrich (currently Merck Life Science S.r.l., Milano, Italy), respectively. Acetone (99+%) was purchased from Alfa Aesar (Thermo Fisher (Kandel) GmbH, Kandel, Germany).
Different types of GRM were selected for the present study, among materials with relatively large commercial availability and focusing on low surface oxidation. Selection was neither aimed to be comprehensive nor to represent all the different production methods and producers, but was exclusively carried out to cover a wide span GRM structural features, including lateral size, surface area and defectiveness. The main structural features of the selected GRM are summarized in Table 1. It is worth mentioning that, independently on the terminology used by the producers of the commercial products addressed here, all the different grades are considered to be graphite nanoplates, accordingly with terminology proposed by Bianco et al. [35 (link)] and will be referred in this work to as GRM-#, as assigned in Table 1. All the materials were used as received. Furthermore, GRM−4 and GRM-5 were selected to undergo annealing for 1 h at 1700 °C at ~50 Pa in a vacuum oven (Pro.Ba., Cambiano, Italy) to decrease the structural defectiveness, as previously reported [58 (link)]. High-temperature annealed material are referred to as GRM-4T and GRM-5T.