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The effect of functionalized graphene sheets (FGS) on the synthesis and materials properties of PMMA nanocomposites has been studied. The esterified GO was used to perform the surface initiated atom transfer radical polymerization (SI-ATRP) of MMA and the effects of ligand type, ligand:CuBr ratio and supported initiator concentration on the synthesis and properties of hybrid nanocomposites are studied at 95 8C. The nanocomposites prepared via SI-ATRP showed improved damping and film formation as compared to the peroxide polymerized composite from acrylated GO. The nanocomposites showed higher thermal stability, rheological and mechanical properties that varied with the FGS initiator content. The water contact angle of PMMA increases from 698 to 828 in the nanocomposite prepared with 2.33 wt% FGS content.

Conjugated polymer‐layered filler nanocomposites have received extensive interest as multifunctional materials in various futuristic applications. In this study, the effect of graphene oxide (GO) particle size on the synthesis, optical, and electrochemical properties of in situ prepared graphene oxide (GO)‐poly(3‐hexylthiophene) (P3HT) nanocomposites have been studied. The intercalation of GO with P3HT is inferred from shifting and broadening of the characteristic D‐ and G‐bands of GO in Raman spectra and also the vibrational frequencies in FTIR. This interaction is further confirmed from increase of the optical band gap and the ellipsometry data. The UV–visible absorption maximum (λmax) of P3HT decreases from 438 to 418 nm in the nanocomposite owing to ionic interactions between GO and the polymer causing a decrease of the polymer conjugation length. Compared to the homopolymer, the emission maximum of the composite is broadened and enhanced in intensity with 10 wt% GO but emission quenching is observed with GO nanoparticles. The evidence of polymer intercalation was also deduced from the determination of the basal spacing and unit cell dimensions of GO, using X‐ray diffraction data. Morphological studies using field emission scanning electron microscopy suggest that the crystalline rod‐like structures observed in the homopolymer have changed to more amorphous, flaky, and porous structures. The cyclic voltammetry studies show an increase in current with increasing GO content in the porous nanocomposites. POLYM. COMPOS., 38:852–862, 2017. © 2015 Society of Plastics Engineers

The synthesis of graphene oxide (GO)-polystyrene (PS) Pickering emulsions, as environment-friendly nanostructures suitable for novel applications, has received significant attention in recent years. In this work, the synthesis and characterization of GO-PS nanocomposites through seeded emulsion polymerization and the selective light reflection properties of dry films have been reported. Amphiphilic molecule sulfonated 3-pentadecyl phenol was used as a co-surfactant to stabilize GO dispersions during the emulsion polymerization process. The particle size of the dispersions as measured by dynamic light scattering decreases from 540 nm, for PS without any GO, to 88 nm with 1 wt% GO content. Scanning electron microscopy studies show a uniform size distribution of the composite particles prepared with GO. The dried films show a structural color that varies with the GO content. The self-assembly behavior of the dried film was further studied using reflectance spectroscopy, which shows a red shift of the reflectance maximum from 440 to 538 nm as the GO loading was increased from 0.2 to 0.5 wt%, respectively, indicating a different microstructure. X-ray diffraction, transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used to study the morphology and structure of the composite particles on drying. The AFM study confirms the non-spherical shape of the particles. Thermogravimetric analysis shows improved thermal decomposition characteristics of the nanocomposite films.

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The synthesis and properties of comb‐like polymer‐graphene nanocomposites via surface initiated atom transfer radical polymerization is reported. The crystallization temperature (Tc) and melt temperature (Tm) of the comb‐like homopolymer increases from −18 to −8 °C and 1 to 11 °C, respectively, in the nanocomposite synthesized with 0.6 wt % graphene initiator. The rheological properties like modulus and complex viscosity of the nanocomposite show a twofold increase. Transmission electron microscopy results of the nanocomposite show a well‐intercalated structure with nanoscale distribution of graphene domains and in scanning electron microscopy a sheet‐like structure with corrugations, and crumples are seen. The hydrophobicity, as measured by water contact angle, increases from 101° in the homopolymer to 118° in the nanocomposite. The nanocomposites exhibit substantial increase in adhesive strength on different substrates, with peel strength increasing by more than 1000 times, as compared to the homopolymer. The improved tack and adhesion properties of the nanocomposites suggest them as novel materials for adhesive applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45885.

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