Solvent Mixing Method Research Articles

Renewable Lignosulfonate-Assisted Synthesis of Hierarchical Nanoflake-Array-Flower ZnO Nanomaterials in Mixed Solvents and Their Photocatalytic Performance.

With the assistance of sodium lignosulfonate, hierarchical nanoflake-array-flower nanostructure of ZnO has been fabricated by a facile precipitation method in mixed solvents. The sodium lignosulfonate amount used in our synthetic route is able to fine-tune ZnO morphology and an abundance of pores have been observed in the nanoflake-array-flower ZnO, which result in specific surface area reaching as high as 82.9 m2 · g−1. The synthesized ZnO exhibits superior photocatalytic activity even under low-power UV illumination (6 W). It is conjectured that both nanoflake-array structure and plenty of pores embedded in ZnO flakes may provide scaffold microenvironments to enhance photocatalytic activity. Additionally, this catalyst can be used repeatedly without a significant loss in photocatalytic activity. The low-cost, simple synthetic approach as well as high photocatalytic and recycling efficiency of our ZnO nanomaterials allows for application to treat wastewater containing organic pollutants in an effective way.

Fabrication and characterisation of low density polyethylene (LDPE)/multi walled carbon nanotubes (MWCNTs) nano-composites

Carbon nanotubes (CNT) have shown extraordinary electrical, mechanical properties as well as many other physical properties. The aim of this study is to explore the scope of CNT/LDPE nano-composites for engineering applications. Nano-composites of LDPE and MWCNT are generally prepared by using the melt blending method but in the present investigation these have been prepared by using solvent mixing method. Xylene has been used as a solvent which can dissolve low density polyethylene (LDPE) at about 125°C. The solution of LDPE in xylene has been ultrasonicated with various percentages of MWCNT (0, 1, 2, 5, 10wt% of MWCNT) composite to form thin film after drying. MWCNT used in this study have been synthesised by electric arc discharge method. Characteristics of these composites have been determined by Raman spectroscopy and scanning electron microscopy (SEM). Raman spectroscopy revealed variation in intensity of CNT's peak with variation in concentration of CNT. The results indicated that intensity of CNT's peak was found to increase with the increase in concentration of CNT which indicated the type of interaction between polymer and CNT. SEM analysis reveals CNT-polymer interfacial adhesion and shows agglomeration of CNT's at some locations and presence of individual tubes at other locations. These investigations show that LDPE/MWCNT composites can be fabricated using simple solvent mixing method. Further investigation on the effect of MWCNT on mechanical, electrical and thermal properties of LDPE based composites are in progress.

Narrow-linewidth red-emission Eu3+-doped TiO2 spheres for light-emitting diodes

In this work, the amorphous Eu3+-doped TiO2 spheres were synthesized by low cost mixed-solvent method, while the anatase and rutile spheres can be obtained by annealing the as-synthesized amorphous TiO2 spheres at elevated temperatures. The optical properties of Eu3+-doped TiO2 spheres were also investigated, and strong red emission (centered at 610 nm) with narrow line-width of 30 nm was observed under 465 nm or 394 nm excitations for the Eu3+-doped anatase TiO2 spheres. Our findings indicate the potential of using Eu3+-doped TiO2 spheres to achieve red emission with InGaN blue light emitting diodes (LEDs). Owing to the high light extraction efficiency in the GaN-based LEDs using anatase TiO2 spheres as demonstrated in our previous works, this work shows the strong potential of Eu3+-doped TiO2 spheres as the red phosphor material for high efficiency GaN-based white light-emitting diode.

Dispersion of Graphene Nanoplatelets in Polylactic Acid with the Aid of a Zwitterionic Surfactant: Evaluation of the Shape Memory Behavior

ABSTRACTDevelopments in the dispersion of graphene nanoplatelets in polylactic acid were achieved with the aid of a zwitterionic surfactant. The graphene nanoplatelet surface modification was tracked by Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and elemental analysis. Different amounts of graphene nanoplatelets and surface-modified graphene nanoplatelets (3 and 6 phr) were used to prepare the polylactic acid nanocomposite through a solvent-mixing method. It was found that surface-modified graphene nanoplatelets were exfoliated and homogeneously dispersed in the polylactic acid matrix. Better dispersion of surface-modified graphene nanoplatelets compared with graphene nanoplatelets was due to enhancement of the polymer–graphene interaction induced by the zwitterionic surfactant. The shape memory properties of nanocomposites were evaluated using thermomechanical analysis. The obtained results revealed that the shape memory performance of nanocomposite samples was affected by the degree of dispersion. Higher shape recovery of nanocomposite samples in comparison with that of neat polylactic acid was obtained, which originated from their higher elastic glassy modulus. Up to 91% shape recovery was determined in nanocomposite samples containing surface-modified graphene nanoplatelets, which was attributed to the good dispersion of surface-modified graphene nanoplatelets in the polylactic acid matrix.

Influence of MWCTs and nanometal oxide/MWCTs hybrids on the thermal conduction of their acrylic-based nanocomposites

In this study, acrylic-based nanocomposites containing different contents of multi-walled carbon nanotubes (MWCNTs) and metal oxide nanoparticles (i.e., TiO2, CuO and Fe2O3) were fabricated by solvent mixing method. The thermal conductivity of these samples was evaluated. The results indicated that the thermal conductivity of all fabricated samples was significantly improved even at small loading of MWCNTs. It was found that the thermal conductivity was enhanced by increase in MWCNTs content up to 5 wt%. Similarly, the metal oxide nanoparticles caused up to 75 % increment in thermal conductivity at 1.5 wt% of their loading in acrylic film. Contrary to expectations, the thermal conductivity of acrylic film was more increased by nanometal oxides (i.e., TiO2, CuO and Fe2O3) than MWCNTs. The effect of hybridizing of nanometal oxide particles (1.5 wt%) and MWCNTs (1.5 wt%) on thermal conduction was investigated as well. It was found that hybridizing improved thermal conductivities by about 85, 94 and 97 % for Fe2O3, TiO2 and CuO, respectively. Finally, the effects of TiO2 pigment and CaCO3 extender on the thermal conductivity of acrylic polymer and nano-TiO2 acrylic composites were studied. It was found that TiO2 could increase considerably thermal conduction of its acrylic films and acrylic nanocomposites.

Structure and crystallization behaviour of syndiotactic polystyrene/layered double hydroxide nanocomposites

AbstractSyndiotactic polystyrene (sPS) based polymer nanocomposites have been prepared using surfactant‐free layered double hydroxides (SF‐LDHs) by a modified solvent mixing method with different loadings of 1, 2.5, 5 and 10 wt%. The nanocomposite preparation process involves a wash treatment of as‐prepared SF‐LDHs in an appropriate organic solvent followed by gel formation in a non‐polar solvent. The gel was directly used to make highly dispersed polymer nanocomposites. The influence of highly dispersed SF‐LDH platelets on the crystallization, polymorphism, thermal stability and flame retardancy of sPS was examined. It was shown that SF‐LDHs significantly enhance the crystallization rate of sPS and favour the formation of the thermodynamically stable β form along with the α form of sPS. Moreover, highly dispersed SF‐LDHs decrease the heat release rate and total heat release of sPS indicating the enhancement of flame‐retardant properties of sPS. In this way, it was found that the dispersed SF‐LDH platelets act as a multifunctional nanofiller for sPS. © 2015 Society of Chemical Industry

Controllable growth of bulk cubic-phase CH3NH3PbI3single crystal with exciting room-temperature stability

To obtain bulk cubic CH3NH3PbI3, chlorobenzene was employed to regulate the CH3NH3PbI3 γ-butyrolactone solution with high saturated solubility at room temperature and a high yield of crystal at 60 °C. As a result, bulk cubic CH3NH3PbI3 single crystal was successfully synthesized for the first time in mixed-solvent method at 60 °C, which is a little higher than the tetragonal–cubic phase inversion temperature.

Bulk Manufacture of Complex Geometry Millirod Implants and their Degradation and Drug Delivery Characteristics

This study evaluated the impact of manufacturing process modifications aimed at the bulk manufacture of curcumin implants for diabetic neuropathy pain relief. Poly (caprolactone) (PCL) and curcumin were blended using cryomilling as an alternative to the solvent mixing method which has higher manufacturing and time delay costs. X-ray diffraction (XRD) was used to characterize the resulting mixture to determine the efficacy of cryomilling as an option for blending curcumin and PCL powders. By adopting compression molding as a manufacturing method we were able to create implant molds featuring threaded geometry on the millirod surface. Implants were subsequently evaluated in vitro for 30 days. Curcumin loaded millirod implants with a complex threaded surface geometry were found to have a higher, but not significant, percent mass loss after degradation and average daily curcumin release than the cylindrical implants. It can be concluded that the utilization of cryomilling for the creation of curcumin loaded implants in bulk is an easier to manipulate and more cost effective method of combining PCL and curcumin without sacrificing implant effectiveness.

Preparation of 4,4′-diaminostilbene-2,2′-disulfonic acid intercalated LDH/polypropylene nanocomposites with enhanced UV absorption property

The UV absorber 4,4′-diaminostilbene-2,2′-disulfonate (DASDSA) has been successfully intercalated into an inorganic host Zn2Al layered double hydroxide (Zn2Al-DASDSA LDH), which is expected to lead stabilization and protection of this thermally unstable UV absorber. Using a modified solvent mixing method, polypropylene/AMO-Zn2Al-DASDSA LDH (PP/AMO-LDH; AMO = aqueous miscible organic treated) nanocomposites were prepared using unmodified PP at various LDH loadings of 0.2–4 wt%. The characterization data indicated that AMO-LDH nanoparticles were evenly dispersed within the PP matrix because of the excellent compatibility between PP and the AMO-LDH. The resistance to thermal degradation of PP/AMO LDH nanocomposites was significantly increased even with very low LDH loadings. The 50% weight loss temperature (T0.5) of PP was increased by 43°C with 4 wt% LDH. UV analysis demonstrated that adding AMO-Zn2Al-DASDSA LDH could significantly enhance the UV absorption capacity of PP. For the enhancement of the photo-stability of PP, the performance of AMO-Zn2Al-DASDSA was much better than the control material Zn2Al-NO3. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

Effect of reaction temperature on surface morphology and photoelectric properties of ZnO grown by hydrothermal method in mixed solvent

ZnO thin films were prepared by hydrothermal method in mixed solvent with different reaction temperatures. Microstructure, surface morphology, optical properties and UV photoresponse of the thin films have been investigated by means of X-ray diffractometer, scanning electron microscopy, laser micro-Raman spectrometer, UV–Vis spectrophotometer and interactive source meter instrument. The results indicated that ZnO thin films consist of ZnO nanoparticles with hexagonal wurzite structure. A small quantity of Zn(OH)2 appear as reaction temperature increase to 125 °C. ZnO thin film grown at 175 °C consists of many densely vertically aligned ZnO nano rods on the substrate and has the best preferential c-axis orientation. Three peaks centered at about 446, 568 and 1150 cm−1 have been attributed to E 2(high), A 1(LO) and 2A 1(LO) phonon mode. Broadening of the visible emission band may be attributed to abundant surface defects and surface states of the thin films. Variation of the E g may be attributed to the synergy of surface morphology and oxygen-vacancy (VO) density. The fast and slow UV photo response may be attributed to the adsorption and photo desorption of oxygen molecules on the surface of ZnO thin films and exchange process between oxygen gas and native deep defect level, respectively.

Ethylene-VInyl acetate/LDH nanocomposites with enhanced thermal stability, flame retardancy, and rheological property

In this contribution, ethylene-vinyl acetate (EVA)/Zn2Al-X layered double hydroxides (LDHs) nanocomposites containing different interlayer anions including CO32–, NO3–, Cl–, SO42– were synthesized using solvent mixing method for the first time. The influence of the interlayer anions of LDHs on the thermal stability, flame retardancy, and rheological behaviors of these nanocomposites were investigated in detail. The results indicated that both the thermal stability and the flame retardancy could be significantly enhanced, and the extent was highly dependent on the type of interlayer anions that were intercalated in LDHs. The influence of different anions on the storage and loss moduli followed the order of SO42– > NO3– > CO32– > Cl–, suggesting that the interlayer anions significantly affect the rheological behaviors of the nanocomposites as well. This work is of great importance to both the academic and industrial fields since it demonstrated that a proper selection of the interlayer anions and an optimization of the chemical composition are crucial for the practical application of such nanocomposites. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

Polypropylene/Layered Double Hydroxide (LDH) Nanocomposites: Influence of LDH Particle Size on the Crystallization Behavior of Polypropylene.

Highly dispersed isotactic polypropylene (iPP) nanocomposites were prepared by incorporating two different sized Mg-Al LDH nanoparticles with different loadings from 1 to 10 wt % using a modified solvent mixing method. Larger sized LDH nanoparticles (∼3-4 μm) were prepared from the gel form of Mg-Al LDH, and the smaller sized nanoparticles (∼50-200 nm) were prepared by sonication of as-synthesized LDH particles. Such obtained LDH nanoparticles were carefully characterized using wide-angle X-ray diffraction (WAXD), transmission electron microscopy, and scanning electron microscopy. WAXD and atomic force microscopy results indicate that the LDH nanoparticles were highly dispersed in the iPP matrix. The influence of LDH nanoparticles size and concentration on the thermal stability, spherulitic morphology, melting behavior, isothermal crystallization kinetics, and lamellar structure of iPP were investigated. Incorporation of low loadings of sonicated LDH particles (e.g., 1-2.5 wt %) show substantial effect on thermal stability, spherulite size, crystallinity, and crystallization half-time and lamellar morphology of iPP compared to the pure iPP and that of nanocomposites with larger LDH particles with same loadings. The better nucleation ability of iPP in the presence of sonicated LDH can be attributed to the high surface area of LDH nanoparticles along with its better dispersibility within the polymer matrix. The incorporation of LDH nanoparticles does not change the crystallization growth mechanism and crystal structure of iPP.

Preparation and properties of a flexible night vision imaging system filter for avionic LED displays

A flexible near-infrared (NIR) absorption filter well suited for use as a front surface filter for night vision imaging system (NVIS) LED displays was prepared by using a transparent polymer film and acrylic resin as substrate, NIR-dyes NIR787 and NIR860 as functional additives through the solvent mixing method. In particular, this new dye-based NVIS filter material offers sharp spectral cut-off and excellent extinction in the NIR (665–930 nm) along with an appropriate transmittance in the visible spectrum (400–700 nm). The optical performance of the filter was studied, the optimal dosage of NIR787 and NIR860 was determined and the results showed there was a good linear relationship between amount of NIR-dyes and light transmittance. In addition, the filter kept good environmental stability after cyclic humid heat test, high temperature aging test, low temperature aging test and photostability test.

Porous Materials: Submicrometer‐Sized ZIF‐71 Filled Organophilic Membranes for Improved Bioethanol Recovery: Mechanistic Insights by Monte Carlo Simulation and FTIR Spectroscopy (Adv. Funct. Mater. 4/2015)

Uniform submicrometer-sized ZIF-71 crystals are prepared via a simple mixed-solvent method for the fabrication of high quality defect-free PDMS mixed-matrix membranes. As reported by L. H. Wee, I. F. J. Vankelecom, and colleagues on page 516, these membranes demonstrate significant improvement for pervaporation recovery of bioethanol. The host–guest chemistry of ethanol-water in the cages of ZIF-71 is unraveled by the combination of FTIR spectroscopy and molecular simulations.

Hydrothermal synthesis of TiO 2 /reduced graphene oxide nanocomposite with enhanced photocatalytic activity

The composite of peanut-like TiO2 nanoparticles and reduced graphene oxide (rGO) was successfully synthesised via a facile one-step hydrothermal method in mixed solvents of diethanol amine and distilled water. The crystallite, morphology and structure features of the composite were characterised by X-ray diffraction, Brunauer-Emmett-Teller specific area analysis, transmission electron microscopy and high-resolution transmission electron microscopy. The results indicated that the as-synthesised TiO2 was of peanut-like shape with about 21–32 nm in length and was anchored on the surface of the rGO sheet. In addition, the TiO2/rGO composite presented excellent photocatalytic activity of rhodamine B under visible light irradiation compared with commercial Degussa P25. A proposed mechanism for the photocatalytic process is also discussed.

N-Hexane, Methyl Ethyl Ketone and Chloroform Solvents for Oil Recovery from Refinery Waste

Considerable amount of oily waste is generated from petroleum refinery in Malaysia. A typical refinery produces about 40 tons of sludge per month. Disposing via land filling (common method) is becoming less accepted and more expensive. As a result, refineries and other facilities have accumulated large volumes of this waste in makeshift landfills or other storage areas. For this reason solvent extraction method has been selected for oil recovery and to minimize the solid waste. Three solvents (chloroform, MEK, and n-hexane) and two extraction methods (sludge–solvent mixing method , and Soxhlet apparatus) were applied to recover the oil from the refinery sludge. Soxhlet extraction method has shown higher efficiency in extraction than sludge-solvent mixing method. Soxhlet extraction method using MEK solvent can recover about 48.3 % of oil, as compared to mixing method which accounts to only about 32.5 % of recovered oil. It has an added recovery of about 7.1 %, 15.8 % and 5.7 % for n-hexane, MEK and chloroform solvents respectively. FTIR results confirmed that MEK has the highest capability to extract hydrocarbon from refinery waste.

Low-Temperature Synthesis and Photoluminescence Properties of Wurtzite Three-Dimensional ZnS Nanostructures

Wurtzite three-dimensional ZnS nanostructure has been synthesised under low temperature (180°C) via solvothermal method in mixed solvents of ethylenediamine and ethylene glycol. The phase structure, morphology and optical properties have been characterized by X-ray (XRD), scanning electron microscope (SEM) and photoluminescence spectra (PL). Through the change of reaction time and the mixed solvent ratio, the properties of three-dimensional ZnS have been discussed in this paper.

Non‐enzymatic electrochemical sensors for the detection of H2O2based on Mn3O4octahedron submicrostructures

In this reported work, Mn3O4 octahedron submicrostructures (Mn3O4 OSMs) were obtained through a facile solvothermal method in mixed solvent. The authors have modified a glassy carbon electrode (GCE) with Mn3O4 OSMs and Nafion to obtain a sensing platform (Mn3O4 OSMs/Nafion/GCE) for the non-enzymatic detection of H2O2. The resulting Mn3O4 OSMs/Nafion/GCE exhibited good electrochemical catalytic activity towards the reduction of H2O2 in a phosphate buffered solution (0.1 M, pH = 7.0). The linear detection range was estimated to be in the range from 5 µM to 17 mM (R = 0.9998), and the detection limit was estimated to be 1.5 µM at S/N = 3. Real sample analyses show that the sensor developed in this work could be efficiently used for the determination of H2O2.

A noncovalent functionalization approach to improve the dispersibility and properties of polymer/MoS 2 composites

In the evolution of high performance layered inorganic compounds/polymer nanocomposites, homogeneous dispersion of inorganic nanoplatelets in the polymer matrix and exact interface control are difficult to achieve due to the potent interlayer cohesive energy and surface inactiveness of the nanocomposites. Pristine MoS2 exhibits poor solubility in both water and organic solvents. Herein, it is necessary to modify the surface of molybdenum disulfide (MoS2) nanosheets with functional groups, in order to enhance its dispersity and compatibility in various solvents and polymer matrices. In this paper, we have reported a convenient method to modify MoS2 nanosheets with common cationic surfactant and polymer, these organic modified MoS2 nanosheets dispersed well in organic solvents and aqueous solution simultaneously. This well dispersion can be used to prepare polymer/MoS2 nanocomposites by a simple solvent mixing method which was found to display an exfoliation structure of MoS2 nanosheets and improve the performances of the polymer nanocomposites. With the addition of 3 wt% CTAB-MoS2, T10% and T50% of the samples are increased by 60 °C, respectively. Moreover, the storage modulus of sample PS/3% CTAB-MoS2 had 84% increment compared with that of pure PS at 30 °C.

Synthesis of Highly Efficient Flame Retardant High-Density Polyethylene Nanocomposites with Inorgano-Layered Double Hydroxides As Nanofiller Using Solvent Mixing Method

High-density polyethylene (HDPE) polymer nanocomposites containing Zn2Al-X (X= CO3(2-), NO3(-), Cl(-), SO4(2-)) layered double hydroxide (LDH) nanoparticles with different loadings from 10 to 40 wt % were synthesized using a modified solvent mixing method. Synthesized LDH nanofillers and the corresponding nanocomposites were carefully characterized using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, etc. The thermal stability and flame retardancy behavior were investigated using a thermo gravimetric analyzer and microscale combustion calorimeter. Comparing to neat HDPE, the thermal stability of nanocomposites was significantly enhanced. With the addition of 15 wt % Zn2Al-Cl LDH, the 50% weight loss temperature was increased by 67 °C. After adding LDHs, the flame retardant performance was significantly improved as well. With 40 wt % of LDH loading, the peak heat release rate was reduced by 24%, 41%, 48%, and 54% for HDPE/Zn2Al-Cl, HDPE/Zn2Al-CO3, HDPE/Zn2Al-NO3, and HDPE/Zn2Al-SO4, respectively. We also noticed that different interlayer anions could result in different rheological properties and the influence on storage and loss moduli follows the order of SO4(2-) > NO3(-) > CO3(2-) > Cl(-). Another important finding of this work is that the influence of anions on flame retardancy follows the exact same order on rheological properties.