Investigation of covalently grafted polyacrylate chains onto graphene oxide for epoxy composites with reinforced mechanical performance

To enhance the dispersion and interfacial interaction of graphene–epoxy matrix, polyacrylate chains grafted graphene oxide (PA-GO) was manufactured with A-174 functionalized GO (A-GO), methyl acrylate, and glycidyl methacrylate via free-radical random copolymerization technique. Fourier transform infrared, thermogravimetric analysis, X-ray photoelectron spectrum, Raman spectroscopy, X-ray diffraction, transmission electron microscopy, and nuclear magnetic resonance were performed to investigate the structure of A-GO and PA-GO. Then, the PA-GO was incorporated into epoxy resin via in situ solution intercalation dispersion method in order to form an interpenetrating network structure with epoxy resin. Field emission scanning electron microscope results indicate that the PA-GO exhibits excellent dispersion and interfacial compatibility in the epoxy matrix. In compared with pure epoxy, the tensile strength and impact strength of the epoxy composite with 1 wt % PA-GO were shifted from 62.78 ± 2.54 to 70.68 ± 2.02 MPa (about 12.6%) and 3.55 ± 0.41 to 4.98 ± 0.33 kJ m⁻² (about 40.3%), respectively. Moreover, increased storage modulus is also observed in the dynamic mechanical analysis measurements compared with that of neat epoxy resin. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47842.     

Pure and complex nanostructures using poly[bis(triiso‐propylsilylethynyl) benzodithiophene‐bis(decyltetradecyl‐thien) naphthobisthiadiazole], carbon nanotubes and reduced graphene oxide for high‐performance polymer solar cells

Crystallization of poly[bis(triiso‐propylsilylethynyl) benzodithiophene‐bis(decyltetradecyl‐thien) naphthobisthiadiazole] (PBDT‐TIPS‐DTNT‐DT) was investigated in supramolecules based on carbon nanotubes (CNTs) and reduced graphene oxide (rGO) and their grafted derivatives. The principal peaks of PBDT‐TIPS‐DTNT‐DT crystals were in the range 3.50°–3.75°. By grafting the surface of the carbonic materials, the assembling of polymer chains decreased because of hindrance of poly(3‐dodecylthiophene) (PDDT) grafts against π‐stacking. The diameters of CNT/polymer and CNT‐g‐PDDT/polymer supramolecules were 160 and 100 nm. The rGO/polymer supramolecules had the highest melting point (T_m = 282 °C) and fusion enthalpy (ΔH_m = 25.98 J g^?1), reflecting the largest crystallites and the most ordered constituents. Nano‐hybrids based on grafted rGO (276 °C and 28.26 J g^?1), CNT (275 °C and 27.32 J g^?1) and grafted CNT (268 °C and 22.17 J g^?1) were also analyzed. T_m and ΔH_m values were significantly less in corresponding melt‐grown systems. The nanostructures were incorporated in active layers of PBDT‐TIPS‐DTNT‐DT:phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) solar cells to improve the photovoltaic features. The best results were detected for PBDT‐TIPS‐DTNT‐DT:PC₇₁BM:rGO/polymer systems having J_sc = 13.11 mA cm^?2, fill factor 60% and V_oc = 0.71 V with an efficacy of 5.58%. On grafting the rGO and CNT, efficiency reductions were 12.01% (5.58%–4.91%) and 9.34% (4.07%–3.69%), respectively. © 2019 Society of Chemical Industry     

SiO2-covered graphene oxide nanohybrids for in situ preparation of UHMWPE/GO(SiO2) nanocomposites with superior mechanical and tribological properties

The modified Hummer technique was used in the preparation of graphene oxide (GO) nanosheets, and then SiO₂ decorated GO [GO(SiO₂)] nanosheets were synthesized via the sol–gel method. Then, ultrahigh-molecular-weight polyethylene (UHMWPE) nanocomposites loaded with 0.5, 1, 1.5, and 2 wt % of GO(SiO₂) were prepared using magnesium ethoxide/GO(SiO₂)-supported Ziegler–Natta catalysts via the in situ polymerization. Morphological study of the prepared polymer powders was assessed using field-emission scanning electron microscopy, which showed that GO(SiO₂) nanohybrids have been uniformly dispersed and distributed into the UHMWPE matrix. Also, the neat UHMWPE and its nanocomposites were evaluated with different analyses, including viscosity-average molecular weight measurement, differential scanning calorimetry, thermogravimetric analysis, tensile test, scratch hardness, and pin-on-disk test. The characterization of the UHMWPE nanocomposites indicated that many characterizations, including the mechanical, thermal, and tribological properties of UHMWPE, were significantly improved by incorporation of these new nanosheets in spite of the molecular weight reduction of the polymeric matrix and the improved flowability and processability of the produced nanocomposite. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47796.     

Size effects of graphene oxide on mixed matrix membranes for CO2 separation

Graphene oxide (GO)‐polyether block amide (PEBA) mixed matrix membranes were fabricated and the effects of GO lateral size on membranes morphologies, microstructures, physicochemical properties, and gas separation performances were systematically investigated. By varying the GO lateral sizes (100–200 nm, 1–2 μm, and 5–10 μm), the polymer chains mobility, as well as the length of the gas channels could be effectively manipulated. Among the as‐prepared membranes, a GO‐PEBA mixed matrix membrane (GO‐M‐PEBA) containing 0.1 wt % medium‐lateral sized (1–2 μm) GO sheets showed the highest CO₂ permeation performance (CO₂ permeability of 110 Barrer and CO₂/N₂ mixed gas selectivity of 80), which transcends the Robeson upper bound. Also, this GO‐PEBA mixed matrix membrane exhibited high stability during long‐term operation testing. Optimized by GO lateral size, the developed GO‐PEBA mixed matrix membrane shows promising potential for industrial implementation of efficient CO₂ capture. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2843–2852, 2016     

Preparation of functional reduced graphene oxide and its influence on the properties of polyimide composites

Homogeneous dispersion and strong filler–matrix interfacial interactions were vital factors for graphene for enhancing the properties of polymer composites. To improve the dispersion of graphene in the polymer matrix and enhance the interfacial interactions, graphene oxide (GO), as an important precursor of graphene, was functionalized with amine‐terminated poly(ethylene glycol) (PEG–NH₂) to prepare GO–poly(ethylene glycol) (PEG). Then, GO–PEG was further reduced to prepare modified reduced graphene oxide (rGO)–PEG with N₂H₄·H₂O. The success of the modification was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, and Raman spectroscopy. Different loadings of rGO–PEG were introduced into polyimide (PI) to produce composites via in situ polymerization and a thermal reduction process. The modification of PEG–NH₂ on the surface of rGO inhibited its reaggregation and improved the filler–matrix interfacial interactions. The properties of the composites were enhanced by the incorporation of rGO–PEG. With the addition of 1.0 wt % rGO–PEG, the tensile strength of PI increased by 81.5%, and the electrical conductivity increased by eight orders of magnitude. This significant improvement was attributed to the homogeneous dispersion of rGO–PEG and its strong filler–matrix interfacial interactions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45119.     

Simultaneous reduction and surface functionalization of graphene oxide and the application for rubber composites

The simultaneous reduction and functionalization of graphene oxide (GO) was realized through a chemical grafting reaction with a functionalization agent N,N-bis(3-aminopropyl)methylamine (APMEL). The reduced and functionalized reduced GO (rGO-APMEL) sheets can be well dispersed in water without any added surfactant and the formed stable rGO aqueous dispersion can be kept for a long time, which can be used for the preparation of rubber–graphene (GE) composites by latex mixing. The electrostatic interaction between rGO–APMEL (positively charged) and natural rubber latex particles (negatively charged) leads to the formation of NR/rGO–APMEL composites with strong interaction. Compared with blank NR, the tensile strength and modulus for NR/rGO–APMEL increase with the rGO–APMEL loading. Especially, when the filler content is 5 phr, the tensile strength of NR/rGO–APMEL-5 increases by 32.7%, as a control the tensile strength of NR/GO-5 and NR/rGO-5 decrease by 20.1 and 15.6%, respectively. The entanglement-bound rubber tube model was used to analyze the reinforcing effect of GE on NR/rGO–APMEL nanocomposites at a molecular level. This study may provide us a novel approach to prepare well dispersed and exfoliated rGO–polymer nanocomposites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47375.     

An investigation of the mechanism of graphene toughening epoxy

The three different sized chemical functionalized graphene (GO) sheets, namely GO-1 (D₅₀ = 10.79 μm), GO-2 (D₅₀ = 1.72 μm) and GO-3 (D₅₀ = 0.70 μm), were used to fabricate a series of epoxy/GO nanocomposites. Fracture toughness of these materials was assessed. The results indicate that GO sheets were dramatically effective for improving the fracture toughness of the epoxy at a very significant low loading. The enhancement of the epoxy toughness was strongly dependent on the size of GO sheets incorporated. GO-3 with smaller sheet size gave the maximum reinforcement effect compared with GO-1 and GO-2. The incorporation of only 0.1 wt% GO-3 was observed to increase the fracture toughness of pristine epoxy by ∼75%. The toughening mechanism was well understood by fractography analysis of the tested samples. Massive cracks in the fracture surfaces of the epoxy/GO nanocomposites were observed. The GO sheets effectively disturbed and deflected the crack propagation due to its two dimensional structure. GO-3 sheets with smaller size were highly effective in resisting crack propagation, and a large area of whitening zone was observed. The incorporation of GO also enhanced the stiffness and thermal stability of the epoxy.     

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.     

Chemical Functionalization of Graphene Oxide by Poly(styrene sulfonate) Using Atom Transfer Radical and Free Radical Polymerization: A Comparative Study

Poly(sodium styrenesulfonate)-functionalized graphene was prepared from graphene oxide, using atom transfer radical polymerization and free radical polymerization. In atom transfer radical polymerization route, the amine-functionalized GO was synthesized through hydroxyl group reaction of GO with 3-amino propyltriethoxysilane. Atom transfer radical polymerization initiator was grafted onto modified GO (GO-NH₂) by reaction of 2-bromo-2-methylpropionyl bromide with amine groups, then styrene sulfonate monomers were polymerized on the surface of GO sheets by in situ atom transfer radical polymerization. In free radical polymerization route, the poly(sodium 4-styrenesulfonate) chains were grafted on GO sheets in presence of Azobis-Isobutyronitrile as an initiator and styrene sulfonate monomer in water medium. The resulting modified GO was characterized using range of techniques. Thermal gravimetric analysis, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy results indicated the successful graft of polymer chains on GO sheets. Thermogravimetric analysis showed that the amount of grafted polymer was 22.5 and 31?wt% in the free radical polymerization and atom transfer radical polymerization methods, respectively. The thickness of polymer grafted on GO sheets was 2.1?nm (free radical polymerization method) and 6?nm (atom transfer radical polymerization method) that was measured by atomic force microscopy analysis. X-ray diffractometer and transmission electron microscopy indicated that after grafting of poly(sodium 4-styrenesulfonate), the modified GO sheets still retained isolated and exfoliated, and also the dispersibility was enhanced.     

Study of the partial wetting morphology in polylactide/poly[(butylene adipate)‐co‐terephthalate]/polyamide ternary blends: case of composite droplets

The prediction of the morphology of ternary polymer blends requires a good knowledge of the values of the three interfacial tensions. We selected three polymers, either biobased or biodegradable, polyamide (PA), poly[(butylene adipate)‐co‐terephthalate] (PBAT) and polylactide (PLA), and we accurately measured their interfacial tensions using the retraction method, varying the molar mass or inverting the phases. The following values of interfacial tension were obtained: γ_PBAT/PLA = 3.3 ± 0.7 mN m^?1, γ_PA/PLA = 5.6 ± 0.3 mN m^?1 and γ_PBAT/PA = 3.0 ± 0.4 mN m^?1. These values were used to calculate the spreading coefficients giving rise to two negative coefficients and one coefficient close to zero. Ternary blends with various compositions, two different levels of viscosity for PBAT and different processing conditions were prepared. There was a very good agreement between the predictions of the spreading theory, when using the values of interfacial tension of the right order of magnitude, and the observed morphologies, whatever the polymer serving as a matrix. When PLA or PBAT was chosen as the matrix, the ternary blend morphology was composed of composite droplets, presenting a partial wetting morphology, dispersed in the polymer matrix. This morphology was observed whatever the composition, the viscosity of the PBAT phase and the processing conditions. A further calculation of the free energy confirmed this morphology. The formation process of this semi‐encapsulated morphology was observed during blending. © 2018 Society of Chemical Industry     

High‐Performance Nanocomposites of Sodium Carboxymethylcellulose and Graphene Oxide

High‐performance nanocomposites of NaCMC with GO are produced by solution casting. FESEM images reveal a good homogeneous dispersion of GO in the NaCMC matrix. The composite formation is facilitated by H‐bonding interaction between GO and NaCMC. T_g of the composites increases with increasing GO concentration. The storage modulus (G′) exhibits a maximum 174% increase over NaCMC at 1 wt% GO. The mechanical properties of the composites exhibit highest increase of tensile stress and Young's modulus of 188 ± 4% and 154 ± 11%, respectively, for 1 wt% GO. Analysis of Young's modulus (E_y) data using the Halpin‐Tsai equation suggests that the E_y data are close to the unidirectional orientation at >0.5 wt% GO, indicating more efficient load transfer at these compositions.

     

Bone Tissue Engineering of HA/COL/GO Porous Nanocomposites with the Ability to Release Naproxen: Synthesis,Characterization, and In Vitro Study

In the present research, porous hydroxyapatite/collagen/graphene oxide (HA/COL/GO) nanocomposites were synthesized using the freeze-drying method for naproxen delivery. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), and Brunauer–Emmett–Teller (BET) techniques were applied to analyze the synthesized specimens. In addition, the loading of naproxen and release behavior (pH 7.4 and T?=?37 °C) of the prepared nanocomposites were studied via UV–Vis spectrophotometry. The FE-SEM analysis revealed that HA/COL/GO nano-composites had a rod-like structure and the morphological change in the HA/COL/GO nano-composites confirmed that graphene oxide (GO) sheets and HA/COL nano-particles were successfully incorporated where the nanocomposites were synthesized with size smaller than 50 nm. BET analysis was utilized to confirm the meso and macrostructure of specimens with an average pore diameter within 15–103 nm as well as the BET surface area of 21–178 m²/g. The application of synthesized samples for naproxen delivery in vitro was investigated. As the weight ratio of GO increased, so did the percentage of drug-loading; for the HA/COL/GO-3 sample where the graphene oxide (GO) amount was maximum, the percentage of drug loading capacity (LC%) and percentage of encapsulation efficiency (EE%) were obtained 38.7% and 84.8%, respectively. Naproxen release results in phosphate buffer saline (PBS) confirmed that the initial release occurred in all synthesized nanocomposites within the first 24 h, after which the release rate gradually declined to about 14 days. Under optimal conditions, the HA/COL/GO-3 sample retained about 39.2% of the loaded drug after 14 days, as some of the drug molecules were deeply embedded in the HA/COL/GO-3 sample. Furthermore, the results revealed that the degradation rates of the synthesized nanocomposites can be controlled by adjusting the amount of graphene oxide (GO). Thus, the results show that the samples synthesized in this research can suitable candidates for continuous release of naproxen and bone tissue engineering.

     

Synthesis and study of some newer polyamides for semipermeable membrane

A series of novel polyamides was prepared by low temperature solution polycondensation of N-(p/m-aminobenzoyl aminoacetyl)-N'-(4/3-aminobenzoyl) hydrazine with different diacid chlorides in dry N,N-Dimethylacetamide (DMAC). The properties of the polyamides for membrane processing were studied with the help of infrared spectra, inherent viscosity, differential thermal, and thermogravimetric analysis. The inherent viscosities were measured in concentrated sulfuric acid at 25±5°C and were in the range of 0.35–0.89 dL/g. The thermogravimetric data in air indicate that the initial decomposition temperature was in the range of 175–200°C. The polymer melt temperature (T_m) and glass transition temperature (T_g) were in the range of 230–450°C and 153.3–300°C, respectively.     

Antibacterial films with enhanced physical properties based on poly (vinyl alcohol) and halogen aminated-graphene oxide

Graphene oxide (GO) nanosheets as great nanofiller have been utilized for the enhancement of a polymer matrix. In this work, polymeric N-halamine poly[5,5-dimethyl-3-(3′-triethoxysilylpropyl)hydantoin] (PSPH) was covalently grafted onto GO, which was denoted as GO-PSPH. The chlorinated GO-PSPH (GP-Cl) was then mixed with poly (vinyl alcohol) (PVA) solution to obtain the PVA/GP-Cl hybrid films. The as-prepared hybrid films were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectra. Compared with PVA film, the addition of GP-Cl into PVA matrix endowed the film with enhanced thermal and mechanical properties, and the crystallinity, tensile strength, and Young's modulus increased by 45, 21, and 246%, respectively. It can be deduced that the interfacial interaction between PVA matrix and GP-Cl nanosheets was the crucial factor for the physical enhancement. Furthermore, the synergistic effect between GO and polymeric N-halamine greatly improved the antibacterial activities of the hybrid films with 3.95 logs reduction of Staphylococcus aureus and 4.53 logs reduction of Escherichia coli O157:H7 with 30 min of contact time, respectively. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48176.     

Thermal analysis of ethylene–propylene copolymer-grafted-glycidyl methacrylate

The thermal properties of ethylene–propylene copolymer grafted with glycidyl methacrylate (EP-g-GMA) were investigated by using differential scanning calorimetry (DSC). Compared to the plain ethylene–propylene copolymer (EP), peak values of melting temperature (T_m) of the propylene sequences in the grafted EP changed a little, crystallization temperature (T_c) increased about 8–12°C, and melting enthalpy (ΔH_m) increased about 4–6 J/g. The isothermal and nonisothermal crystallization kinetics of grafted and ungrafted samples was carried out by DSC. Within the scope of the researched crystallization temperature, the Avrami exponent (n) of ungrafted sample is 1.6–1.8, and those of grafted samples are all above 2. The crystallization rates of propylene sequence in EP-g-GMA were faster than that in the plain EP and increased with increasing of grafted monomer content. It might be attributed to the results of rapid nucleation rate. © 1996 John Wiley & Sons, Inc.     

Improvement of Medical Applicability of Hydroxyapatite/Antimonous Oxide/Graphene Oxide Mixed Systems for Biomedical Application

This study supports the binary and ternary merging tactic, this methodology is useful in the creation of new features that lacked in the parent constituents. Ra develops to reach its peak of 4.25 nm upon HAP/Sb₂O₃/GO which is shadowed by HAP/Sb₂O₃ with 3.87 nm. EDX technique offers quantitative, and qualitative elemental composition of the studied composite, where C, O, P, Ca, and Sb elements records 17.14, 66, 8.7, 7.57, and0.58%, respectively. Consequently, the composition is pure. Also, The BET technique’s resultant surface area is 39.49 for HAP/Sb₂O₃, and 50.76 m²/g for HAP/Sb₂O₃/GO. Additionally, The (HAP/GO, and HAP/Sb₂O₃/GO) ceramic composites microhardness was 3.2?±?0.2 GPa for binary composite, and 3.5?±?0.3 GPa for ternary composite. Thus, GO nano-materials enhance mechanical behavior. Applicably, the merging of the three components in one ternary nanocomposite presents the highest viability with 98.4?±?0.8%, besides the highest antibacterial performance by 15.2?±?0.4 mm for Escherichia coli and 16.1?±?0.5 mm for Staphylococcus aureus.

     

Effect of interfacial chemistry on crystallization of polypropylene/multiwall carbon nanotube nanocomposites

This study systematically investigates the polymer–carbon nanotube (CNT) interaction when the interphase is tailored. Maleic anhydride‐grafted‐polypropylene (MA‐g‐PP) or polypropylene (PP) was noncovalently coated onto acid functionalized multiwall nanotube (f‐MWNT) through solution mixing. These coated f‐MWNTs were melt microcompounded with neat PP to form PP/f‐MWNT nanocomposites. The effects of functional groups and the thin layer of solution processed polymers, namely, MA‐g‐PP or PP, at the PP/f‐MWNT interface on crystallization and on melting behavior of matrix PP were investigated. The results were compared with a pristine MWNT (p‐MWNT) incorporated system. It was shown that PP coated CNTs can serve as a strong nucleating agent for templated polymer crystal growth. Unlike other PP nanocomposites in the literature, a relatively high shift of 7°C in melting peak maximum (T_p), along with a sharp melt endotherm was achieved with the addition of 0.3 wt% f‐MWNT via PP/f‐MWNT master batch. This indicates refinement of matrix PP crystalline region due to the tailored f‐MWNT surface chemistry. With a designed self‐seeding and templated crystal growth approach, columnar crystalline interphases were found surrounding MWNT which melted at 10.5°C higher temperature than neat PP crystallized without undergoing the same heat treatment protocol. POLYM. ENG. SCI., 59:1570–1584 2019. © 2019 Society of Plastics Engineers     

Preparation of compatibilizer with large specific surface and its application in immiscible polymer blends with ultra‐high molecular weight

In this work, a compatibilizer (UHMWPE‐g‐GO) with large specific surface was prepared from graphene oxide (GO) and ultra‐high molecular weight polyethylene (UHMWPE). First, GO was modified by 2, 3‐epoxypropyltrimethylammonium chloride (GTA), subsequently grafted with UHMWPE. UHMWPE‐g‐GO was used to compatibilize the immiscible monomer casting (MC) nylon/UHMWPE blends. With the addition of very low content of UHMWPE‐g‐GO, the compatibility of UHMWPE and the matrix (MC nylon) was remarkably improved without visible agglomerates, which was proved by photographs, scanning electron microscope, dynamic thermomechanical analysis, and contact angle measurement. Therefore, thermal stability, mechanical and tribological properties were obviously increased. A dramatic increment of 94.1% in the impact strength and a decrement of 39.4% in the coefficient friction were observed in the presence of UHMWPE‐g‐GO in the immiscible polymer blends. The approach used in this work was an efficient strategy for immiscible polymer blends with ultra‐high molecular weight. POLYM. ENG. SCI., 57:335–344, 2017. © 2016 Society of Plastics Engineers     

Polymer brushes on graphene oxide for efficient adsorption of heavy metal ions from water

The pollution of heavy metal ions in water poses a serious threat to human being and ecosystems. Here, we report polyamidoxime (PAO) brush grafted graphene oxide (GO) as a highly efficient adsorbent for extraction of toxic metal cations from water. Surface-initiated atom transfer radical polymerization was used to grow polyacrylonitrile (PAN) brushes on GO, followed by conversion of the nitrile groups in PAN into amidoxime groups, which had high binding affinity toward heavy metal cations. The PAO brush grafted GO demonstrated significantly fast adsorption kinetics and large adsorption capacity. At optimal pH 5, the PAO brush grafted GO can achieve maximum adsorption capacities of 116.7 mg g⁻¹ for Pb(II), 258.6 mg g⁻¹ for Ag(I), 192.2 mg g⁻¹ for Cu(II), and 167.9 mg g⁻¹ for Fe(III), which were significantly larger than those of small molecule functionalized GO. Mechanism analysis suggested that the enhanced adsorption performance was due to the myriads of functional groups in PAO brushes that were easily accessible to metal ions because of the swelling of the polymer brushes in water. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48156.     

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