Synthesis of pyrene‐capped polystyrene by free radical polymerization and its application in direct exfoliation of graphite into graphene nanosheets

Abstract

It is of great practical significance to acquire pyrene-capped polymer, which has proven an excellent dispersant of nanocarbons, in an accessible way. Taking synthesis of pyrene-capped polystyrene (PyPS) as the example, free radical polymerization was demonstrated to be an attractive option to satisfactorily fulfill such mission. For this, a new azo-based pyrenyl compound was designed, synthesized, and used as initiator. The molecular structure of PyPS was studied as a function of polymerization temperature and content of chain transfer agent of 1-dodecanethiol. Following the successful synthesis, a PyPS polymer structured as 1.04 pyrene groups per chain was chosen as dispersant for preparation of graphene. The results showed that 0.2 mg/mL of PyPS in chloroform permits 67.4 lg/mL of graphene nanosheets to be prepared by liquid-phase exfoliation of graphite. In contrast, only 8.5 lg/mL of graphene nanosheets could be obtained in pure chloroform.

rGO/GO Nanosheets in Tribology: From the State of the Art to the Future Prospective

“…Furthermore, π-π stacking is more suitable for pristine graphene than rGO and GO due to the absence of oxygen groups that affect sp 2 extensions. There is no sufficient information about the performance of such systems in the oil medium, but the nearest analogy could be made with studies performed in the hydrophobic chloroform [78], where pyrene linked to polymers was utilized for graphene dispersion. Additionally, a study was conducted in chloroform using styrene and 2 vinylpyridine copolymers [79] revealing enhanced graphene stability for concentrations ranging from 0.29-0.219 mgL −1 .…”

Strong Interaction with Carbon Filler of Polymers Obtained by Pyrene Functionalized Hoveyda-Grubbs 2nd Generation Catalyst

“…To enhance these properties and consequently the multi-functionality in advanced applications, it is often necessary to improve the physicochemical and mechanical properties of the polyolefins by introducing fillers into the matrix. In fact, the addition of additives, in particular of nanometric dimensions, has allowed their use for advanced technologies [2,3,4]. Carbon additives such as carbon blacks, carbon nanofiber, carbon nanotubes, and graphene have been largely utilized to improve mechanical properties, thermal stability, flame resistance, and the thermal and electrical conductivities of a pure polyolefin [4,5,6,7,8,9,10,11,12,13,14].…”

“…In fact, the addition of additives, in particular of nanometric dimensions, has allowed their use for advanced technologies [2,3,4]. Carbon additives such as carbon blacks, carbon nanofiber, carbon nanotubes, and graphene have been largely utilized to improve mechanical properties, thermal stability, flame resistance, and the thermal and electrical conductivities of a pure polyolefin [4,5,6,7,8,9,10,11,12,13,14]. The addition of nanometric filler into polymers enabled important applications in radiation and electromagnetic shielding, antistatic, shrinkage- and corrosion-resistant coatings, light-emitting devices, and batteries [2,3,4,5,6,7,8,9,10,11].…”

“…A problem that arises frequently using these fillers is represented by their tendency to form bundles and agglomerates, providing weak interaction within the polymer. Recently, exfoliated graphite or graphene have been tested as promising forms of nanofiller for polyolefins, generating a new class of composite materials with relatively small amounts of nanofiller concentration that can have extensive applications in the aerospace, automotive and construction industries, thanks to the ease of processing and the high strength-to-weight ratio [2,3,4,5,6,7,8,9,10,11]. Graphene has excellent physical-chemical properties: remarkable surface area and optical transmittance [12].…”

“…These terminals can provide interaction with the carbon fillers and facilitate the dispersion of the latter in the polymer matrix. The employment of the non-oxidized filler may allow all of the previously mentioned interesting carbonaceous material applications [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23].…”