Synthesis and properties of click coupled graphene oxide sheets with three‐dimensional macromolecules

A facile click chemistry approach to the functionalization of three‐dimensional hyperbranched polyurethane (HPU) to graphene oxide (GO) nanosheets is presented. HPU‐functionalized GO samples of various compositions were synthesized by reacting alkyne‐functionalized HPU with azide‐functionalized GO sheets. The morphological characterization of the HPU‐functionalized GO was performed using transmission electron microscopy and its chemical characterization was carried out using Fourier transform‐infrared spectroscopy, nuclear magnetic resonance spectroscopy, and X‐ray photoelectron spectroscopy. The graphene sheet surfaces were highly functionalized, leading to improved solubility in organic solvents, and consequently, enhanced mechanical, thermal, and thermoresponsive and photothermal shape memory properties. The strategy reported herein provides a very efficient method for regulating composite properties and producing high performance materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43358.     

Synthesis and exfoliation of isocyanate-treated graphene oxide nanoplatelets

A number of functionalized graphite oxides were prepared by treatment of graphite oxide (GO) with organic isocyanates. These isocyanate-treated GOs (iGOs) can then be exfoliated into functionalized graphene oxide nanoplatelets that can form a stable dispersion in polar aprotic solvents. Characterization of iGOs by FT-IR spectroscopy and elemental analysis suggested that the isocyanate treatment results in the functionalization of the carboxyl and hydroxyl groups in GO via formation of amides and carbamate esters, respectively. The degree of GO functionalization can be controlled via either the reactivity of the isocyanate or the reaction time. When used with functionalized isocyanates, the described methodology allows for the elaboration of graphene oxide nanoplatelets with different surface functional groups.     

Epoxy/p‐phenylenediamine functionalized graphene oxide composites and evaluation of their fracture toughness and tensile properties

In an attempt to enhance the mechanical properties of epoxy/graphene‐based composites, the interface was engineered through the functionalization of graphene oxide (GO) sheets with p‐phenylenediamine; this resulted in p‐phenylenediamine functionalized graphene oxide (GO–pPDA). The morphology and chemical structure of the GO–pPDA sheets were studied by spectroscopic methods, thermal analysis, X‐ray diffraction, and transmission electron microscopy. The characterization results show the successful covalent functionalization of GO sheets through the formation of amide bonds. In addition, p‐phenylenediamine were polymerized on graphene sheets to form crystalline nanospheres; this resulted in a GO/poly(p‐phenylenediamine) hybrid. The mechanical properties of the epoxy/GO–pPDA composite were assessed. Although the Young's modulus showed improvement, more significant improvements were observed in the strength, fracture strain, and plane‐strain fracture toughness. These improvements were attributed to the unique microstructure and strong interface between GO–pPDA and the epoxy matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43821.     

In‐plane functionalizing graphene nanolayers with polystyrene by atom transfer radical polymerization: Grafting from hydroxyl groups

Graphene oxide (GO) was prepared from the oxidation of graphite and then it was functionalized with (3‐aminopropyl)triethoxysilane (APTES) from hydroxyl groups by a coupling reaction. Subsequently, alpha‐bromoisobutyryl bromide (BiBB) was attached to the APTES groups to yield initiator anchored graphene nanolayers (GOHBr). Then, GOHBr was used in different amounts as the precursor for atom transfer radical polymerization of styrene to evaluate the effect of graphene loading along with the graft density on the properties of final product. Successful in‐plain attachment of APTES, BiBB, and polystyrene to GO was evaluated by Fourier transform infrared spectroscopy. Graphene interlayers expansion by oxidation and functionalization processes was evaluated using X‐ray diffraction. The ordered and disordered crystal structures of carbon were evaluated by Raman spectroscopy. Morphology of graphene nanolayers was studied by scanning electron microscopy and also transmission electron microscopy. POLYM. COMPOS., 35:386–395, 2014. © 2013 Society of Plastics Engineers     

Thermal and mechanical properties of liquid silicone rubber composites filled with functionalized graphene oxide

To improve the thermal and mechanical properties of liquid silicone rubber (LSR) for application, the graphene oxide (GO) was proposed to reinforce the LSR. The GO was functionalized with triethoxyvinylsilane (TEVS) by dehydration reaction to improve the dispersion and compatibility in the matrix. The structure of the functionalized graphene oxide (TEVS‐GO) was evaluated by Thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectra, X‐ray diffraction (XRD), and energy dispersive X‐ray spectroscopy (EDX). It was found that the TEVS was successfully grafted on the surface of GO. The TEVS‐GO/LSR composites were prepared via in situ polymerization. The structure of the composites was verified by FTIR, XRD, and scanning electron microscopy (SEM). The thermal properties of the composites were characterized by TGA and thermal conductivity. The results showed that the 10% weight loss temperature (T₁₀) increased 16.0°C with only 0.3 wt % addition of TEVS‐GO and the thermal conductivity possessed a two‐fold increase, compared to the pure LSR. Furthermore, the mechanical properties were studied and results revealed that the TEVS‐GO/LSR composites with 0.3 wt % TEVS‐GO displayed a 2.3‐fold increase in tensile strength, a 2.79‐fold enhancement in tear strength, and a 1.97‐fold reinforcement in shear strength compared with the neat LSR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42582.     

Interface engineering for the improvement of mechanical and thermal properties of covalent functionalized graphene/epoxy composites

Functionalized reduced graphene oxide (GO)/epoxy composites are fabricated through solution mixing. GO is functionalized using 3‐amino‐1,2,4‐triazole (TZ) in presence of potassium hydroxide (KOH). KOH is expected to serve dual role as catalyst for nucleophilic addition reaction between GO and TZ, and also as reducing agent. The grafting of TZ moiety on GO is confirmed by Fourier transform infrared spectroscopy, X‐ray diffraction, and thermogravimetric analysis. The prepared composites show remarkable improvement in mechanical and thermal stability. The fracture toughness of the composites (critical stress intensity factor, K_IC) achieved from single edge notched bending testing is improved by ～111% against pure epoxy at 0.1 wt % loading of TZ functionalized GO. Further, the tensile strength and Young's modulus are improved by ～30.5% and 35%, respectively. Thermal stability of the composites as investigated by thermogravimetric analysis showed 29 °C rise in onset degradation temperature for 0.1 wt % TZ functionalized GO incorporated composite. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46124.     

Effect of octa(aminopropyl) polyhedral oligomeric silsesquioxane (OapPOSS) functionalized graphene oxide on the mechanical,thermal, and hydrophobic properties of waterborne polyurethane composites

A novel graphene nanomaterial functionalized by octa(aminopropyl) polyhedral oligomeric silsesquioxane (OapPOSS) was synthesized and then confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), Raman spectroscopy, X‐ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy with energy‐dispersive X‐ray spectroscopy (SEM EDX), atomic force microscopy, and X‐ray diffraction. The obtained functionalized graphene (OapPOSS‐GO) was used to reinforce waterborne polyurethane (WPU) to obtain OapPOSS‐GO/WPU nanocomposites by in situ polymerization. The thermal, mechanical, and hydrophobic properties of nanocomposites as well as the dispersion behavior of OapPOSS‐GO in the polymer were investigated by TGA, a tensile testing machine, water contact angle tests, and field emission SEM, respectively. Compared with GO/WPU and OapPOSS/WPU composites, the strong interfacial interaction between OapPOSS‐GO and the WPU matrix facilitates a much better dispersion and load transfer from the WPU matrix to the OapPOSS‐GO. It was found that the tensile strength of the OapPOSS‐GO/WPU composite film with 0.20 wt % OapPOSS‐GO exhibited a 2.5‐fold increase in tensile strength, compared with neat WPU. Better thermal stability and hydrophobicity of nanocomposites were also achieved by the addition of OapPOSS‐GO. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44440.     

Characterization and performance of dodecyl amine functionalized graphene oxide and dodecyl amine functionalized graphene/high‐density polyethylene nanocomposites: A comparative study

Dodecyl amine (DA) functionalized graphene oxide(DA‐GO) and dodecyl amine functionalized reduced graphene oxide (DA‐RGO) were produced by using amidation reaction and chemical reduction, then two kinds of well dispersed DA‐GO/high‐density polyethylene (HDPE) and DA‐RGO/HDPE nanocomposites were prepared by solution mixing method and hot‐pressing process. Thermogravimetric, X‐ray photoelectron spectroscopy, Fourier transforms infrared spectroscopy, X‐ray diffractions, and Raman spectroscopy analyses showed that DA was successfully grafted onto the graphene oxide surface by uncleophilic substitution and the amidation reaction, which increased the intragallery spacing of graphite oxide, resulting in the uniform dispersion of DA‐GO and DA‐RGO in the nonpolar xylene solvent. Morphological analysis of nanocomposites showed that both DA‐GO and DA‐RGO were homogeneously dispersed in HDPE matrix and formed strong interfacial interaction. Although the crystallinity, dynamic mechanical, gas barrier, and thermal stability properties of HDPE were significantly improved by addition of small amount of DA‐GO or DA‐RGO, the performance comparison of DA‐GO/HDPE and DA‐RGO/HDPE nanocomposites indicated that the reduction of DA‐GO was not necessary because the interfacial adhesion and aspect ratio of graphene sheets had hardly changed after reduction, which resulting in almost the same properties between DA‐GO/HDPE and DA‐RGO/HDPE nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39803.     

Grafting polystyrene with various graft densities through epoxy groups of graphene nanolayers via atom transfer radical polymerization

A double bond and amine group containing chemical (OD) was synthesized by coupling reaction of ethylenediamine and 3‐(chlorodimethylsilyl)propyl methacrylate. Subsequently, graphene oxide (GO) was functionalized with OD in different densities via ring opening of its epoxy groups. The graphene containing double bond (GOD) was incorporated into polystyrene (PS) chains by a grafting through atom transfer radical polymerization. Grafting of OD at the surface of GO was confirmed by Fourier transform infrared spectroscopy and thermogravimetric analysis (TGA). The interlayer spacing of the graphenes was evaluated by X‐ray diffraction. Molecular weight and PDI values of the free and attached PS chains were studied by size exclusion chromatography. TGA was also used to study the degradation points, char values, and grafting ratios. Relaxation of PS chains in the presence of graphene layers was evaluated by differential scanning calorimetry. Scanning electron and transmission electron microscopies show that flat graphene layers are wrinkled during oxidation and functionalization processes. POLYM. COMPOS., 38:2450–2458, 2017. © 2015 Society of Plastics Engineers     

Synthesis of magnetic citric‐acid‐functionalized graphene oxide and its application in the removal of methylene blue from contaminated water

A magnetic nanocomposite of citric‐acid‐functionalized graphene oxide was prepared by an easy method. First, citric acid (CA) was covalently attached to acyl‐chloride‐functionalized graphene oxide (GO). Then, Fe₃O₄ magnetic nanoparticles (MNPs) were chemically deposited onto the resulting adsorbent. CA, as a good stabilizer for MNPs, was covalently attached to the GO; thus MNPs were adsorbed much more strongly to this framework and subsequent leaching decreased and less agglomeration occurred. The attachment of CA onto GO and the formation of the hybrid were confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction spectrometry and transmission electron microscopy. The specific saturation magnetization of the magnetic CA‐grafted GO (GO‐CA‐Fe₃O₄) was 57.8 emu g^?1 and the average size of the nanoparticles was found to be 25 nm by transmission electron microscopy. The magnetic nanocomposite was employed as an adsorbent of methylene blue from contaminated water. The adsorption tests demonstrated that it took only 30 min to attain equilibrium. The adsorption capacity in the concentration range studied was 112 mg g^?1. The GO‐CA‐Fe₃O₄ nanocomposite was easily manipulated in an external magnetic field which eases the separation and leads to the removal of dyes. Thus the prepared nanocomposite has great potential in removing organic dyes. © 2014 Society of Chemical Industry     

Latex co‐coagulation approach to fabrication of polyurethane/graphene nanocomposites with improved electrical conductivity,thermal conductivity,and barrier property

This study describes a simple and effective method of synthesis of a polyurethane/graphene nanocomposite. Cationic waterborne polyurethane (CWPU) was used as the polymer matrix, and graphene oxide (GO) as a starting nanofiller. The CWPU/GO nanocomposite was prepared by first mixing a CWPU emulsion with a GO colloidal dispersion. The positively charged CWPU latex particles were assembled on the surfaces of the negatively charged GO nanoplatelets through electrostatic interactions. Then, the CWPU/chemically reduced GO (RGO) was obtained by treating the CWPU/GO with hydrazine hydrate in DMF. The results of X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Raman analysis showed that the RGO nanoplatelets were well dispersed and exfoliated in the CWPU matrix. The electrical conductivity of the CWPU/RGO nanocomposite could reach 0.28 S m^?1, and the thermal conductivity was as high as 1.71 W m^?1 K^?1. The oxygen transmission rate (OTR) of the CWPU/RGO‐coated PET film was significantly decreased to 0.6 cm³ m^?2 day^?1, indicating a high oxygen barrier property. This remarkable improvement in the electrical and thermal conductivity and barrier property of the CWPU/RGO nanocomposite is attributed to the electrostatic interactions and the molecular‐level dispersion of RGO nanoplatelets in the CWPU matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43117.     

Polymer nanocomposites: In situ polymerization of polyamide 6 in the presence of graphene oxide

Polyamide 6 (PA6)/graphene oxide (GO) nanocomposites were prepared via in situ , ring opening polymerization of ε‐caprolactam in the presence of both dried powder and colloidally dispersed single layer GO. Characterization of the composites and GO (both as received and after removal from the composites) was carried out using atomic force microscopy (AFM), Fourier transform infra‐red spectroscopy (FTIR), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), thermogravimetric analysis, differential scanning calorimetry and tensile testing. Reduction in the GO during polymerization was observed. So too was functionalization of the GO flakes with PA6 chains. FTIR demonstrates the retention of some carbonyl oxygen functionalities after polymerization. AFM imaging indicated the presence of single layer GO and the sheet height increased to ∼4 nm for graphene sheets after polymerization. This suggests the graphene acts as a base for polymer chain formation, leading to good interfacial interaction between the filler and matrix. Raman data show no evidence of the restoration of sp2 hybrid as a result of polymerization. The nanocomposites are thermally stable while molecular weight and crystallinity have both been affected by GO inclusion. A percentage linear increase in Young's modulus was observed as colloidally dispersed GO content increased. POLYM. COMPOS., 38:528–537, 2017. © 2015 Society of Plastics Engineers     

Peptide‐functionalized reduced graphene oxide as a bioactive mechanically robust tissue regeneration scaffold

Bioactive, synthetic materials represent next‐generation composites for tissue regeneration. Design of contemporary materials attempts to recapitulate the complexities of native tissue; however, few successfully mimic the order in nature. Recently, graphene oxide (GO ) has emerged as a scaffold due to its potential for bioactive functionalization and long‐range order instilled by the self‐assembly of graphene sheets. Chemical reduction of GO results in a more compatible material with enhanced properties but compromises the ability to functionalize the graphenic backbone. However, using Johnson–Claisen rearrangement chemistry, functionalization is achieved that is not liable to reduction. From reduced Claisen graphene, we polymerized short homopeptides from α ‐amino acid N ‐carboxyanhydride monomers of glutamate and lysine to result in functionalized graphenes (pGlu‐rCG and pLys‐rCG ) that are cytocompatible, degradable, and bioactive. Exposure to NIH‐3T3 fibroblasts and RAW 264.7 macrophages revealed that the materials are cytocompatible and do not alter important sub‐cellular compartments. Powders were hot pressed to form mechanically stiff (E ′: 41 and 49 MPa ), strong (UCS : 480 and 140 MPa ), and tough (U _T: 2898 and 584 J m^?3 × 10⁴) three‐dimensional constructs (pGlu‐rCG and pLys‐rCG, respectively). Overall, we report a robust chemistry and processing strategy for facile bioactive functionalization of compatible, reduced Claisen graphene for three‐dimensional biomedical applications. © 2017 Society of Chemical Industry     

Influence of structure of amines on the properties of amines‐modified reduced graphene oxide/polyimide composites

Graphene oxide (GO), as an important precursor of graphene, was functionalized using alkyl‐amines with different structure and then reduced to prepare reduced amines grafted graphene oxide (RAGOs) by N₂H₄ · H₂O. The successful chemical amidation reaction between amine groups of alkyl‐amines and carboxyl groups of GO was confirmed by Fourier transform infrared (FTIR), X‐ray photoelectron spectroscopy (XPS), and thermal gravimetric analysis (TGA). Then RAGOs/polyimide nanocomposites were prepared via in situ polymerization and thermal curing process with different loadings of RAGOs. The modification of amine chains lead to homogenous dispersion of RAGOs in the composites and it formed strong interfacial adhesion between RAGOs and the polymer matrix. The mechanical and electrical properties of polyimide (PI) were significantly improved by incorporation of a small amount of RAGOs, the influence of structure of amines grafted on RAGOs on the enhancement effects of composites was discussed. The research results indicated that the proper structure of amine could effectively enhance the properties of composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43820.     

Effect of Dodecyal Amine Functionalized Graphene on the Mechanical and Thermal Properties of Epoxy‐Based Composites

Simultaneous surface functionalization and reduction of graphene oxide (GO) was achieved by using dodecyl amine (DA) as surface modifying agent. The DA modified reduced GO (DA‐G) was used for subsequent preparation of DA‐G/epoxy composites by solution mixing. Fourier transform infrared spectroscopy analysis, X‐ray diffraction (XRD) and electrical conductivity measurements were conducted to establish the concurrent functionalization and reduction of GO. The effect of DA‐G on the epoxy composites at 0 to 0.75 wt% loadings was studied by investigating its static and dynamical mechanical properties. XRD study was performed to verify the dispersion of DA‐G in the epoxy polymer. Field emission scanning electron microscopy was used to investigate the fracture surface morphology of the composites and Transmission electron microscopy was employed to further confirm the dispersion of DA‐G in the matrix. It was found that the tensile strength of the composite was increased by 38.8% with the addition of 0.5 wt% of DA‐G. The good adhesion/interaction between DA‐G and epoxy resulted in the increase of storage modulus; however, glass transition temperature (T_g) value of the composites shifted to lower temperature in comparison to the neat epoxy. Thermogravimetric analysis showed small decrease in onset degradation temperature for the composites as compared to neat epoxy except for the composites containing 0.75 wt% of DA‐G. POLYM. ENG. SCI., 56:1221–1228, 2016. © 2016 Society of Plastics Engineers     

Graphene oxide functionalized by poly(ionic liquid)s for carbon dioxide capture

Poly(ionic liquid)s have been demonstrated as high efficient CO₂ absorbents. In the current study, a kind of poly(ionic liquid)s, Poly[2‐(methacryloyloxy)‐ethyl] trimethylammonium tetrafluoroborate (P[MATMA][BF₄]) was used to functionalize graphene oxide (GO). The hybrid in which P[MATMA][BF₄] was covalently bonded on GO platelets was prepared by a simple method, that is, traditional radical polymerization. The characterizations based on transmission electron microscopy, scanning electron microscope, Fourier transform infrared spectroscopy, Raman spectroscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy demonstrated the graft of P[MATMA][BF₄] on GO. N₂ adsorption measurements indicated that P[MATMA][BF₄] also greatly increased the specific surface area of GO. Due to the higher specific surface area and the CO₂ affinity of P[MATMA][BF₄], the GO‐P[MATMA][BF₄] hybrid exhibited a much higher CO₂ adsorption capacity compared with GO, GO‐NH₂, and P[MATMA][BF₄]. Their study showed that the combinations of poly(ionic liquid)s and GO could be promising CO₂ absorbents. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44592.     

Mechanical and piezo‐resistive properties of styrene–butadiene–styrene copolymer covalently modified with graphene/styrene–butadiene–styrene composites

As novel piezoelectric materials, carbon‐reinforced polymer composites exhibit excellent piezoelectric properties and flexibility. In this study, we used a styrene–butadiene–styrene triblock copolymer covalently grafted with graphene (SBS‐g‐RGO) to prepare SBS‐g‐RGO/styrene–butadiene–styrene (SBS) composites to enhance the organic solubility of graphene sheets and its dispersion in composites. Once exfoliated from natural graphite, graphene oxide was chemically modified with 1,6‐hexanediamine to functionalize with amino groups (GO–NH₂), and this was followed by reduction with hydrazine [amine‐functionalized graphene oxide (RGO–NH₂)]. SBS‐g‐RGO was finally obtained by the reaction of RGO–NH₂ and maleic anhydride grafted SBS. After that, X‐ray diffraction, X‐ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and other methods were applied to characterize SBS‐g‐RGO. The results indicate that the SBS molecules were grafted onto the graphene sheets by covalent bonds, and SBS‐g‐RGO was dispersed well. In addition, the mechanical and electrical conductivity properties of the SBS‐g‐RGO/SBS composites showed significant improvements because of the excellent interfacial interactions and homogeneous dispersion of SBS‐g‐RGO in SBS. Moreover, the composites exhibited remarkable piezo resistivity under vertical compression and great repeatability after 10 compression cycles; thus, the composites have the potential to be applied in sensor production. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46568.     

Synthesis and properties of fluorinated graphene oxide bisphenol a epoxy nanocomposites

This study thoroughly studied the implements of fluorosilane modified graphene oxide (GO) on the mechanical, thermal, and water absorption properties of the epoxy composites built up by specific content of modified GO. Fluorosilane graphene oxide (GOSiF) was analyzed using Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, X‐ray photoelectron spectroscopy, and X‐ray diffractometer. The epoxy composites tensile and bending modulus were increased by 11.46% and 62.25% with 0.1 and 0.5 wt% GOSiF loading, respectively. The good interfacial interaction was observed between epoxy matrix and GOSiF nanosheets under scanning electron microscopy. The thermal stability increases with GOSiF loading. Epoxy composite with 0.3 wt% GOSiF shows 5 °C increases in the T_10%. The residual weight raised by 58.67% with 0.3 wt% GOSiF content. The water absorption study revealed small water uptake was obtained for all GOSiF composites. With 0.3 wt% loading of GOSiF, the maximum water content drops from 4.97% for neat epoxy to 1.98%. POLYM. ENG. SCI., 59:1250–1257 2019. © 2019 Society of Plastics Engineers     

ZrO2 functionalized graphene Oxide/SEBS‐Based nanocomposites for efficient electromagnetic interference shielding applications

ZrO₂‐coated graphene oxide (GO)/SEBS(styrene‐ethylene‐butylene‐styrene)‐based nanocomposites were prepared for use as an electromagnetic interference (EMI) shielding material. Transmission electron microscopy (TEM) reveals almost every individual GO is fully and homogeneously covered with uniform ZrO₂. X‐ray diffraction (XRD) patterns and Differential scanning calorimetry (DSC) revealed increased ordering of ‐(CH₂‐CH₂)n segments in the poly(ethylene‐co‐1‐butene) block of the SEBS matrix in the case of SEBS/ZrO₂‐coated graphene oxide composites than in the SEBS/pristine graphene oxide nanocomposite. Thermogravimetric analysis (TGA) proved better oxidation resistance of SEBS/ZrO₂‐coated GO nanocomposite compared to that of SEBS/pristine GO nanocomposite. The present nanocomposites exhibited excellent EMI shielding effectiveness (SE) over X‐band (8.2 GHz–12.4 GHz) with EMI SE of 37.9 dB. J. VINYL ADDIT. TECHNOL., 25:E130–E136, 2019. © 2018 Society of Plastics Engineers     

In situ development of bio‐based polyurethane‐blend‐epoxy hybrid materials and their nanocomposites with modified graphene oxide via non‐isocyanate route

We developed a series of sunflower oil‐based non‐isocyanate polyurethane (NIPU)‐blend‐epoxy hybrid materials (HNIPUs) and their nanocomposites with amine‐functionalized graphene oxide (AF‐GO). Firstly, carbonated sunflower oil (CSFO) containing five‐membered cyclocarbonate groups was synthesized by the reaction of epoxidized sunflower oil with carbon dioxide (CO₂) at a pressure of 50 bar and temperature of 110 °C. Then, a series of HNIPUs were synthesized using a mixture of CSFO and a commercially available epoxy resin in various amounts (10, 20 and 30 wt% with respect to CSFO) using isophorone diamine as the curing agent. The HNIPU with 30 wt% epoxy showed the best mechanical properties. Finally, nanocomposites of 30 wt% HNIPU‐based composition were prepared with various amounts of AF‐GO (0.3, 0.6 and 1.0 wt%) and were characterized using Fourier transform infrared and ¹H NMR spectroscopies, X‐ray diffraction and scanning electron microscopy. These results emphasize the potentiality of this environmentally friendly approach for preparing renewable HNIPU and nanocomposite materials of high performances. © 2018 Society of Chemical Industry