Covalent functionalization has proven an effective solution for graphene to realize its revolutionary potential in real applications, whereas the platform strategy (a reactive graphene-based material acting as the platform to undergo post-reactions for generation of various graphene-derived materials) is an attractive option to execute efficiently such a task. This contribution demonstrates that 2-(3,4-dihydroxyphenyl) pyrrolidine (DHPP) grafted graphene, G-OH, is a competent platform. Four typical but not exclusive graphene-derived materials have been prepared from G-OH by using the chemical virtue of each DHPP unit having three categories totaling six reactive sites. The controlled feature of 1,3-dipolar cycloaddition for the synthesis of G-OH ensures that the electronic structure and properties of pristine graphene are succeeded largely by G-OH and thus its derivatives. A promising alternative to graphene oxide, which has been widely used as a platform to prepare the graphene-derived materials but suffers from some intrinsic disadvantages, is thus developed.

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 μg/mL of graphene nanosheets to be prepared by liquid-phase exfoliation of graphite. In contrast, only 8.5 μg/mL of graphene nanosheets could be obtained in pure chloroform. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2175–2185

A new type of water-soluble single-walled carbon nanotubes (SWNTs) was synthesized by grafting of dodecyl quaternary ammonium bromides. Results of Fourier transform infrared and proton nuclear magnetic resonance spectroscopic analyses confirmed the successful synthesis. Water-soluble performance of functionalized SWNTs, i.e. N⁺-SWNTs, has been studied in terms of solubility and stability. It was found that the solubility could reach up to 110 mg.l⁻¹ and as-prepared solution possesses a good stability over the PH range of 6.87–11.25. Based on these properties, one of the important applications of N⁺-SWNTs was demonstrated to prepare poly(vinyl alcohol) (PVA) composites. Owing to critical issues of uniform dispersion and enhanced interfacial PVA-nanotube interaction having been simultaneously resolved to a reasonable extent, the composite film with only 0.3 wt% N⁺-SWNTs showed an increase of 33% and 32% in tensile strength and Young's modulus, respectively, over neat PVA film. Moreover, a high optical quality and slightly increased glass transition temperature were also observed. Copyright © 2012 John Wiley & Sons, Ltd.

A new fluorescent copolymer, poly(1-vinylimidazole-co-(1-pyrene) methyl 2-methyl-2-propenote) (VI-co-PyMMP), has been designed and synthesized by a free-radical copolymerization of VI and PyMMP as well as characterized using ultraviolet (UV), Fourier transform infrared spectroscopy (FTIR), ¹H NMR, and fluorescence spectroscopies. The monomer reactivity ratios are determined by two methods of Fineman-Ross (r₁ = 0.28 ± 0.04 for VI, r₂ = 1.32 ± 0.11 for PyMMP) and Kelen-Tüdös (r₁ = 0.23 ± 0.05, r₂ = 1.22 ± 0.12). Based on the reactivity ratios, the monomer sequence lengths and Q and e for PyMMP monomer are further calculated. The results suggest that the copolymerization of VI and PyMMP is a nonideal copolymerization without an azeotropic point (i.e., r₁ < 1, r₂ > 1 and r₁r₂ < 1) and has a low alternation tendency. The conclusions drawn in this work may not only direct the later synthesis of the copolymers but also enrich the database of free-radical copolymerization. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Uniform dispersion and strong interfacial interaction are two critical prerequisites for application of single-walled carbon nanotubes (SWNTs) in polymer composites. To endow the composites with multifunctional feature, no damage on the chemical/electronic structure of SWNTs is also usually required. With these ends in view, two epoxide-containing pyrene derivatives (EpPys) were designed, synthesized, and used as reactive noncovalent dispersants for developing multifunctional epoxy/SWNT composites. One having longer chain length between epoxide group and pyrene moiety, that is, EpPy-16, shows higher dispersing efficiency and provides the nanotube dispersion with better stability, thus picking up for subsequent studies. Systematic characterization on SWNT/EpPy-16 hybrid demonstrates that 13.2 wt % of EpPy-16 is adsorbed on the SWNT surface through strong π-stacking interaction, and intrinsic electronic structure of SWNTs is basically reserved. The solution-based process adopted here preserves the good SWNT dispersing state in dispersion into the composites. Simultaneously, enhanced interfacial interaction is also realized by using EpPy-16, which interacts noncovalently with SWNT but connects covalently to epoxy network. As a result, the composites acquire 37 and 22% increments in tensile strength and Young's modulus, respectively, relative to that of neat resin. A low-electrical percolation threshold of 0.1 wt % SWNTs and improved thermal properties were also observed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Pyrene-capped polystyrene (PyPS) with various molecular weights (M̄_n) was synthesized through the anionic polymerization method and characterized using UV, Fourier transform infrared and NMR spectroscopy and gel permeation chromatography. The polymers were then used for non-covalent functionalization of pristine single-walled carbon nanotubes (SWNTs). The functionalization efficiency was assessed by measuring the SWNT dispersibility in chloroform. In the presence of PyPS, the dispersibility can be as high as 372.5 mg L⁻¹, and the dispersions containing more than 1.25 mg mL⁻¹ of PyPS are very stable with no solid deposits observed after being centrifuged at 5000 rpm for 15 min. Once the PyPS concentration is converted to the molar concentration of the pyrene unit and the dispersibility redefined as nanotube content per molar pyrene unit, the renewed dispersibility is found to be independent of M̄_n of PyPS within the detected M̄_n range. For a certain PyPS polymer, however, both nanotube dispersibility and dispersion stability are strongly dependent on the PyPS concentration. These results suggest that PyPS may be used as an excellent dispersant for subsequent preparation of polystyrene/SWNT composites. Copyright © 2011 Society of Chemical Industry

Grafting of aldehyde structures to single-walled carbon nanotubes (SWNTs) has been carried out to endow the nanotubes with appropriate wettability. The results of Fourier transform infrared (FTIR) spectroscopy, ultraviolin-visible-near infrared (UV-VIS-NIR) spectroscopy, and Raman spectroscopy provide the supporting evidence of aldehyde structures covalently attached to SWNTs. The improved wettability of aldehyde-functionalized SWNTs (f-SWNTs) was demonstrated by their good dispersion in organic medium, namely, ethanol and phenolic resin. The prospective covalent bonding between aldehyde structures on the surfaces of f-SWNTs and phenolic resin makes it possible to prepare an integrated composite with the enhanced-interfacial adhesion. The f-SWNT composites, therefore, show much higher average values of dσ/dW_CNT and dE/dW_CNT (i.e., tensile strength and Young's modulus per unit weight fraction) compared with the composites filled with pristine SWNTs or MWNTs. The respective maxima are 9680 MPa and 320 GPa. It is thus feasible for f-SWNTs to prepare the moderately enhanced but lightweight phenolic composites. Furthermore, the incorporation of f-SWNTs does not limit the application of phenolic resin as insulation material. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6135–6144, 2009