聚苯乙烯/二氧化硅杂化材料的原位制备

采用活性负离子聚合法和末端官能化改性技术合成三乙氧基封端聚苯乙烯,然后用溶胶-凝胶法合成聚苯乙烯(PS)/SiO2杂化材料,用红外光谱、凝胶渗透色谱、差示扫描量热法、热重分析、扫描电子显微镜对PS/SiO2杂化材料的结构和性能进行分析。结果表明:PS/SiO2杂化材料中的PS和SiO2间有化学键相连;PS/SiO2杂化材料中的w(SiO2)为25%时,SiO2是粒径约为180 nm,且粒径分布均匀、有完善球形结构的颗粒,其玻璃化转变温度比纯PS高1.3℃,热稳定性较纯PS高。     

Facile approach to prepare multi-walled carbon nanotubes/graphene nanoplatelets hybrid materials

A facile approach was developed to prepare multi-walled carbon nanotubes/graphene nanoplatelets hybrid materials through covalent bond formation. First, poly(acryloyl chloride) was grafted onto oxidized multi-walled carbon nanotubes through the reaction between the acyl chloride groups of poly and the hydroxyl groups of oxidized multi-walled carbon nanotubes. Second, the remaining acyl chloride groups of poly were allowed to react with the hydroxyl groups of hydroxylated graphene nanoplatelets. Scanning electron microscopy and transmission electron microscopy data showed that the multi-walled carbon nanotubes and graphene nanoplatelets were effectively connected with each other. And Fourier transform infrared spectroscopy data indicated the formation of covalent bonds between carbon nanotubes and graphene nanoplatelets. Conformational changes were monitored by Raman spectroscopy. This novel kind of carbon hybrid materials may have the potential application in a wide field, especially in increasing the toughness and strength of the matrix resin.     

One‐step synthesis of polyaniline nanofibers decorated with silver

Polyaniline (PANI)/silver (Ag) nanocomposites containing PANI nanofibers decorated with well‐dispersed Ag nanoparticles were obtained with interfacial polymerization. It was interesting that silver nitride affected not only the diameter and crystallinity of the PANI nanofibers but also their room‐temperature conductivity. The conductivity increased with increasing Ag loading up to 10 (molar ratio of aniline to silver nitride), but the conductivity moderately decreased with further increasing Ag loading. Scanning electron microscopy and X‐ray diffraction analysis results indicate that the diameter of the PANI nanofibers became smaller and smaller, and their crystallinity got better and better with increasing Ag loading. However, Fourier transform infrared analysis proved that the balance of oxidized and reduced units of PANI became big with increasing Ag loading, which may have resulted in the decreasing conductivity of PANI. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

One‐step solvothermal synthesis of hollow Bi2WO6 photocatalyst

A one‐step solvothermal synthesis of hollow microspherical Bi₂WO₆ nanophotocatalyst was carried out for the first time under the collective action of potassium chloride (KCl) and polyvinylpyrrolidone (PVP). The physicochemical properties such as crystal structure, morphology, specific surface area, and optical properties of the material were characterized by means of XRD, SEM, EDS, UV‐vis, and BET. The effect of KCl and PVP on the morphology control of the product is discussed. Rhodamine B dye in wastewater was used as model pollutant, and the effect of hollow microspherical morphology on photocatalytic activity is discussed. The results presented here provide a simple, effective, and widely applicable approach for the rapid synthesis of special morphology Bi₂WO₆ by a one‐step method.     

S-doped crosslinked porous Si/SiO2 anode materials with excellent lithium storage performance synthesized via disproportionation

The volume expansion during cycling and low electrical conductivity of a Si anode limit its commercial development. Nanostructure can effectively alleviate the volume expansion and doping can increase the electrical conductivity of silicon. Hence, in this paper, uniformly S-doped crosslinked porous Si/SiO₂ (S-doped pSi/SiO₂) were prepared by the disproportionation reaction of SiO at a high temperature. As a bifunctional additive, sulphur can be used to prepare crosslinked porous silicon by a silicon-sulphur reaction. Furthermore, sulphur can improve the conductive properties of the bulk Si via doping. At the same time, residual SiO₂ can also be used as a buffer material. This strategy not only provides space for the volume expansion of silicon, but also enhances its electrical conductivity and improves charge transfer. Consequently, the S-doped pSi/SiO₂ anode exhibits superior cycling capacity and rate performance (1035 mAh·g^?1 at 1 A g^?1 after 300 cycles and an exceptional rate performance of 1233 mAh·g^?1 at 2 A g^?1). Moreover, the electrochemical performance of the S-doped pSi/SiO₂//LiFePO₄ full cell was also evaluated, which exhibits favourable lithium storage performance.     

壳聚糖/纳米SiO_2杂化材料的研究

在甲醇和乙酸介质中,通过酸酐与壳聚糖反应,合成了水溶性的N-酰化壳聚糖,并将纳米二氧化硅颗粒与N-酰化壳聚糖水溶液经溶胶-凝胶过程,制备了壳聚糖/纳米S iO2杂化材料。通过傅立叶变换红外光谱、元素分析、扫描电镜等方法对杂化材料进行了表征,采用热重分析对杂化材料的热性能进行研究。扫描电镜分析结果表明,杂化材料为纳米尺度的无机S iO2加强化的片状材料,S iO2颗粒分散在材料中,形成均匀的表面;热重分析结果表明,杂化材料的热性能有较大提高。     

One‐step synthesis of corn starch urea based acrylate superabsorbents

A one‐step synthesis procedure for starch‐based acrylate superabsorbent polymers was proposed. The reaction conditions that may affect the water absorption capacity were discussed. A transparent gel‐like polymer containing urea (USAP) was successfully obtained by dissolving starch in a NaOH solution without further gelatinizing processing and using AA directly without prior neutralization. Urea was used as the nitrogen source and pore‐forming agent to improve the performance of the USAP. The optimum reaction conditions of the swelling ratio were also studied. A corn starch USAP was synthesized under the optimum conditions, and the water absorbency was 2704 ± 22, 561 ± 39, 100 ± 5, and 96 ± 4 g/g, respectively, in distilled water, running water, physiological saline, and artificial urine. Five kinds of starch‐based USAPs were also successfully prepared under the same conditions with excellent water absorption capacities, revealing that the one‐step method was a more convenient method for a potential industrial application pathway. The polymers were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, and thermogravimetric analysis. The results indicated that the PAA chains were successfully grafted onto the St backbone. However, the St molecular structure was not completely destroyed during the graft polymerization. The thermal analysis and nitrogen content results proved that urea was also involved in the graft copolymerization. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45175.     

Design and synthesis of NiCo2O4/NiCoO2/graphene hybrid nanoarrays with enhanced capacitive performance

NiCo₂O₄/NiCoO₂/graphene hybrid nanoarrays on Ni foam have been designed and synthesized through a hydrothermal method and post-annealing treatment. Highly conductive graphene sheets were embedded into or coated onto the NiCo₂O₄/NiCoO₂ arrays, which strongly affect influence the morphology and electrochemical performance of hybrid nanoarrays. Under the effect of graphene, the architecture of the NiCo₂O₄/NiCoO₂ consists of cluster-like arrays that are self-assembled from numerous nanoneedles and provides more electroactive sites for the redox reaction. However, without the assistance of graphene, the pure NiCo₂O₄/NiCoO₂ exhibits the morphology of flake-like arrays on the Ni foam. The NiCo₂O₄/NiCoO₂/graphene arrays show an ultrahigh capacity of 1439 C g^-1 at a current density of 1 mA cm^-2, which is far larger than that of the pure NiCo₂O₄/NiCoO₂ flake-arrays (695 C g^-1). Furthermore, even at a high current density of 60 mA cm^-2, the NiCo₂O₄/NiCoO₂/graphene arrays maintain a high gravimetric capacity of 1172 C g^-1 (capacity retention: 81.4%), which indicates an excellent rate capability. Further, the hybrid capacitor shows a maximum energy density of 34.3 Wh kg^-1. The present study suggests that the NiCo₂O₄/NiCoO₂/graphene hybrid arrays have great application potential as a positive electrode for hybrid supercapacitors.     

High‐performance antistatic ethylene–vinyl acetate copolymer/high‐density polyethylene composites with graphene nanoplatelets coated by polyaniline

Graphene nanoplatelets coated by polyaniline (GNP@PANI) and ethylene–vinyl acetate (EVA) copolymer–high‐density polyethylene (HDPE) were used for the first time to prepare high‐performance antistatic composites through an effective method that combined solution mixing and melt blending. GNP@PANI nanocomposites were fabricated by in situ polymerization to improve the dispersion of graphene nanoplatelets (GNPs) in the EVA–HDPE matrix and the compatibility between the GNPs and the EVA–HDPE matrix. The GNP@PANI nanocomposites and EVA were first prepared as a premix through solution mixing, and then, the premix and HDPE were prepared as highly antistatic composites through melt blending. The dispersion of the GNPs in the EVA–HDPE matrix and the compatibility between the GNPs and the EVA–HDPE matrix were confirmed by field emission scanning electron microscopy and transmission electron microscopy observations. The GNP@PANI–EVA–HDPE composites met the requirements for antistatic materials when the content of the GNP@PANI nanocomposites was 5 wt % with only about 1 wt % GNPs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45303.     

One‐step synthesis of highly conductive PPy/graphite nanosheets/Gd3+ composites

Highly conductive polypyrrole/graphite nanosheets/Gd³⁺ (PPy/nanoG/Gd³⁺) composites are fabricated via in situ polymerization using p‐toluenesulfonic acid as a dopant and FeCl₃ as an oxidant. The effects of the graphite nanosheets and Gd³⁺ loading on the electrical conductivity are investigated. The maximum conductivity of PPy/nanoG/Gd³⁺ composites about 17.86 S/cm found with 3 wt% graphite nanosheets and 6 wt% Gd³⁺ at room temperature. The results showed that the high‐aspect‐ratio structure of graphite nanosheets played an important role in forming a conducting network in PPy matrix. Thermal gravimetric analysis demonstrates an improved thermal stability of PPy in the PPy/nanoG/Gd³⁺ composites. The microstructures of PPy/nanoG/Gd³⁺ are evidenced by the SEM and TEM examinations. POLYM. COMPOS., © 2011 Society of Plastics Engineers.     

PU/SiO2杂化材料的制备与表征

用溶胶-凝胶法制备了一系列聚氨酯(PU)／SiO2杂化材料,通过扫描电子显微镜和傅里叶变换红外光谱考察了杂化材料的相容性、微观相互作用以及介电性能。实验发现．水和催化剂的用量控制得当可得到分散均匀的杂化材料;在10μm厚的聚对苯二甲酸乙二酯(PET)薄膜上涂有2μm厚的PU／SiO2杂化材料,体系的介电常数较纯PET薄膜提高1倍多。     

Preparation of PDMS/EEC/SiO2 composite super-hydrophobic coatings with excellent anti-guano adhesion performance

A low-cost and no-toxicity approach was presented to fabricate super-hydrophobic coatings via depositing hydroxy-terminated poly-dimethylsioxane and 3,4-epoxycyclohexylmethyl-3′, 4′-epoxycyclohexane carboxylate grafted nano-silica particles on substrates. The surface morphology, wettability, and anti-guano adhesion performance of as-prepared coatings were investigated. Results show the micro-nano hierarchical structures were formed on the surface of as-prepared coatings. The coatings exhibit super-hydrophobicity with a water static contact angle of 156° and sliding angle of 3°. Excellent anti-guano adhesion performances are also exhibited by the coatings, and the residue amount of guano captured by the coating only accounts for 0.3% of that captured by glass surface, making the as-prepared coating a promising candidate as an anti-guano strategy for both industry and everyday life (e.g. insulators for overhead power lines, buildings, statues and cars).     

Tribological characterization of graphene nanoplatelets/alumina particles filled epoxy hybrid nanocomposites

In this work, graphene nanoplatelets have been synthesized using liquid phase exfoliation of graphite flake powder. The exfoliated graphene nanoplatelets were identified and characterized by using UV–Visible–NIR spectroscopy, High resolution transmission electron microscopy, electron diffraction, scanning electron microscopy and X-ray diffraction. The obtained graphene nanoplatelets and nano alumina at various weight ratios were dispersed in an epoxy matrix to enhance the surface roughness (R_a), micro hardness (H_v) and coefficient of friction (CoF) of epoxy hybrid nanocomposites. The results showed that the R_a and CoF value for the combined loading of 0.2 wt% of graphene nanoplatelets and 0.8 wt% of alumina into the epoxy was decreased to 41.02 and 20.01% whereas, the H_v value was increased to 10.04% when compared with the neat epoxy. The improved mechanical and tribological behaviors are suitable for the applications bearing and coating.     

石墨烯携载无机纳米粒子的制备及拉曼性能研究

通过原位复合的方法,在石墨烯片层间掺杂纳米银颗粒,制备出石墨烯/银纳米杂化材料(RGO/Ag)。利用紫外吸收光谱、傅里叶红外光谱、透射电子显微镜(TEM)、XRD、拉曼光谱等对氧化石墨烯(GO)、还原氧化石墨烯(RGO)和石墨烯/银纳米杂化材料(RGO/Ag)进行表征。发现复合材料中的银对石墨烯/银材料有拉曼增强作用,结合TEM对这种增强作用进行研究,发现银颗粒的团聚对这种增强作用有减弱作用。     

A new route to synthesize polyaniline-grafted carboxyl-functionalized graphene composite materials with excellent electrochemical performance

A new route to synthesize polyaniline (PANI)-grafted carboxyl-functionalized graphene (PGCG) composite material is established. In this paper, PGCG is first prepared through a two-step carboxyl-functionalized process. PANI can be grafted and grown on the surface of graphene due to the covalent bonding existing between the carboxyl-functionalized graphene and polyaniline. This method cannot only improve the mechanical performance and adaptive performance of polyaniline effectively, but also reduce the production costs and environmental pollution during the synthetic process. Therefore, a green and industrial synthetic process is achieved. X-ray diffraction (XRD) patterns, X-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared (FTIR) all confirm that composite materials have been prepared successfully. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicate that the as-prepared PGCG has regular structure. Thermogravimetric analysis (TGA) indicates that the addition of graphene nanosheets can significantly improve the thermostability of PANI. Moreover, the as-prepared material exhibits superior electrochemical performance. As an electrode material for supercapacitors, PGCG possesses high specific capacitance of 158 F g^?1 at a scan rate of 25 mV s^?1 and 147 F g^?1 at 50 mV s^?1 in 1 M H₂SO₄. The Nyquist plot also confirms that the PGCG has low charge transfer resistance and good capacitive behavior. These great properties make PGCG a novel electrode material with potential applications in high-performance energy storage devices.     

石墨烯携载无机纳米粒子的制备及拉曼性能研究

通过原位复合的方法,在石墨烯片层间掺杂纳米银颗粒,制备出石墨烯/银纳米杂化材料(RGO/Ag)。利用紫外吸收光谱、傅里叶红外光谱、透射电子显微镜(TEM)、XRD、拉曼光谱等对氧化石墨烯(GO)、还原氧化石墨烯(RGO)和石墨烯/银纳米杂化材料(RGO/Ag)进行表征。发现复合材料中的银对石墨烯/银材料有拉曼增强作用,结合TEM对这种增强作用进行研究,发现银颗粒的团聚对这种增强作用有减弱作用。     

Thermal and electrical conductivity of melt mixed polycarbonate hybrid composites co‐filled with multi‐walled carbon nanotubes and graphene nanoplatelets

In this work, we present thermoplastic nanocomposites of polycarbonate (PC) matrix with hybrid nanofillers system formed by a melt‐mixing approach. Various concentrations of multi‐walled carbon nanotubes (MWCNT) and graphene nanoplatelets (GnP) were mixed in to PC and the melt was homogenized. The nanocomposites were compression molded and characterized by different techniques. Torque dependence on the nanofiller composition increased with the presence of carbon nanotubes. The synergy of carbon nanotubes and GnP showed exponential increase of thermal conductivity, which was compared to logarithmic increase for nanocomposite with no MWCNT. Decrease of Shore A hardness at elevated loads present for all investigated nanocomposites was correlated with the expected low homogeneity caused by a low shear during melt‐mixing. Mathematical model was used to calculate elastic modulus from Shore A tests results. Vicat softening temperature (VST) showed opposite pattern for hybrid nanocomposites and for PC‐MWCNT increasing in the latter case. Electrical conductivity boost was explained by the collective effect of high nanofiller loads and synergy of MWCNT and GnP. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42536.     

Synthesis and characterization of PMMA/SiO2 organic–inorganic hybrid materials via RAFT‐mediated miniemulsion polymerization

In this article, we first carried out the surface modification of SiO₂ using silane coupling agent KH570, and then prepared PMMA/SiO₂ organic–inorganic hybrid materials by conventional free radical polymerization and RAFT polymerization in miniemulsion, respectively. The kinetics comparisons of these two polymerizations were studied. PMMA/SiO₂ hybrid materials were characterized by gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis. Experimental results indicated that the polymerization behavior of MMA in miniemulsion showed controlled/living radical polymerization characteristics under the control of RAFT agent. Incorporation of RAFT agent and SiO₂ nanoparticles improved the thermal properties of polymers, the thermal stability of polymers increased with increasing content of SiO₂ nanoparticles. The structures and morphologies of SiO₂, modified SiO₂, and PMMA/SiO₂ hybrid materials were characterized by FT‐IR and TEM. TEM results showed that the addition of modified SiO₂ nanoparticles to miniemulsion polymerization system obtained different morphology latex particles. Most of modified SiO₂ nanoparticles were wrapped by polymer matrix after polymerization. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers