Beneficial effects of high-pressure homogenization on the dispersion stability of aqueous hydrolysate from Mytilus edulis

Owing to the formation of aggregation and gelation during storage,certain proteins and peptides exhibit limited applications in aqueous protein food products.The purpose of this study was to investigate the influence of homogenization and xanthan gum addition on the dispersion stability of Mytilus edulis hydrolysate(PHM).High-pressure homogenization(HPH)at 360 and 40 bar in the first and second values,respectively,and adding xanthan gum at a concentration of 1 mg/mL showed significantly improvement on the stability of the PHM solution.PHM-xanthan gum solutions(PHMX)showed the highest polypeptide precipitation rate and turbidity retention rate compared with those of PHM.Moreover,the centrifugal precipitation rate of PHMX without HPH was higher than that of homogeneous PHMX.After HPH treatment at 400 bar,the percentage of smaller particles in PHM and PHMX was increased,the aqueous system became more uniform,and the fluorescence intensity reached its maximum.HPH pretreatment improved the polypeptide dispersion stability and turbidity retention rate of PHM and PHMX and reduced the fluorescence intensity.The interactions of xanthan gum and polypeptide render the network microstructure more uniform under the conditions of homogenization,thus improving the dispersion stability of PHMX solutions.Therefore,under the premise of adding xanthan gum,HPH can better enhance the dispersion stability of the polypeptide in PHM.

Preparation of SiO_2 Nanoparticles by Silicon and Their Dispersion Stability

Silicon dioxide sol was synthesized by silicon in the presence of alkali catalyst. SiO_2 nanoparticles (size in 8-15 nm) aqueous dispersion was prepared by using dispersion and surface modification in situ. The effects of reaction time, temperature, medium pH value, dispersant and surface-modifier on their diameters, sizes distribution and dispersion stability were also studied.The experimental results show that the preparation method can effectively resolve the dispersion stability of SiO_2 nanoparticles in water.

Preparation of SiO_2 Nanoparticles by Ion Exchanging and Study on Their Dispersion Stability

By adopting sodium silicate as a major material,SiO_2 nanoparticles (size in 8-15nm) water-dispersiod was prepared by ion exchanging.The effects of sodium silicate concentration,surface-modifying time,temperature and technological conditions on their diameter,size distribution and dispersion stability were also studied.The result show that,the hydrophilic lipophlic and hydrophilic-lipophilic SiO_(2) nanoparticles water-dispersoid can be prepared through different kinds of surface-modifiers and the optimum reaction conditions have been determined as follows:sodium silicate solution concentration:8w%;silicone dosage:3% of the total mass of nano SiO_(2) water-dispersoid;adding way and time of surface-modifier:continual dropping for 2h;surface-modifying temperature:60-70℃.

An IR Study of the Dispersion Stability of Catalyst Powders Dispersed in Solutions of Linear Saturated Polyesters

The conformation of polymers at the solid-liquid interface has been the subject of considerable interest in the fundamental theory and applied practice. In paints and printing inks, dispersions of pigment or filler powders in polymeric binder solutions have to be maintained in the colloidal state. One of the stabilizing mechanisms for paint is the steric stabilization. On the other hand, in the formation reaction of polymer at the solid-liquid interface took place between monomer solutions and solid

Surface-functionalized cellulose nanocrystals(CNC)and synergisms with surfactant for enhanced oil recovery in low-permeability reservoirs

Nanocellulose,a natural polymeric nanomaterial,has attracted significant attention in enhanced oil recovery(EOR)applications due to its abundance,nanoscale,high oil-water interfacial adsorption ef-ficiency.In this study,surface-functionalized cellulose nanocrystals(SF-CNCs)were prepared via hy-drochloric acid hydrolysis and chemical modification,with adaptable nanosize and considerable dispersion stability in low-permeability reservoirs.The SF-CNCs were structurally characterized by FT-IR,Cryo-TEM,which have a diameter of 5-10 nm and a length of 100-200 nm.The SF-CNC dispersions possessed higher stability and stronger salt-tolerance than those of corresponding CNC dispersions,due to the strong hydrophilicity of the sulfonic acid group.It was synergistically used with a non-ionic surfactant(APG1214)to formulate a combined flooding system(0.1 wt%SF-CNC+0.2 wt%APG1214).The combined flooding system exhibits strong emulsification stability,low oil-water interfacial tension of o.03 mN/m,and the ability to alter the wettability for oil-wetting rocks.Furthermore,the combined system was_able to provide an optimum EOR efficiency of 20.2%in low-permeability cores with 30.13×10^(-3)μm^(2).Notably.it can enlarge the sweep volume and increase the displacement efficiency simultaneously.Overall,the newly formulated nanocellulose/surfactant combined system exhibits a remarkable EoR performance in low-permeability reservoirs.

Performance of Polyaniline-coated Short Carbon Fibers in Electromagnetic Shielding Coating

Combined nitric acid oxidation method and polyaniline （PANI）-coated method were applied to modify the surface properties of short carbon fibers （SCF）. The electrical and mechanical properties of acrylic coatings with 50 wt pct PANI-coated carbon fiber were investigated by using scanning electron microscope （SEM）, UV-Vis spectrophotometer, four-probe method and the coaxial cable method. The results of the pH measurement and XPS （X-ray photoelectron spectroscopy） patterns showed that the oxygen functional groups, such as -OH and -COOH, were attached on the carbon fiber surfaces after oxidation treatment. The XPS analysis of PANl-coated oxidized SCF （PAOSCF） revealed that PANI may bond on the surface of oxidized SCF with chemical bonds. SEM images and surface roughness analyses showed that PANl-coated layer changed the surface morphology. Compared with SCF/acrylic coating, the surface resistivity of PAOSCF/acrylic coating decreased from17.1 to 5.3 Ω/sq and the shielding efficiency （SE） value increased from 1.54 to 23.3 dB.

Preparation,Dispersion and Tribological Properties of Oleophilic Lanthanum Hydroxide/Graphene Oxide Nanocomposites

Lanthanum hydroxide/graphene oxide nanocomposites(La(OH)3/GO)modified by octadecylamine(OCA),oleylamine(OLA),and polyvinylpyrrolidone(PVP)were prepared,respectively,as the base oil additives.The dispersion stability of different modified La(OH)3/GO in base oil was studied by means of centrifugation.The tribological properties of oleophilic La(OH)3/GO in base oil were investigated using an UMT ball-disc tribometer.The micro-morphology and chemical composition of the worn surface were characterized by 3 D laser microscope,SEM,EDS,XPS,and Raman spectroscopy,respectively.The wettability performance of the worn surface was also studied based on the contact angle measurements.The test results showed that the OLA-La(OH)3/GO nanocomposites had good dispersion stability in base oil.The anti-wear performance of base oil was improved significantly by the addition of OLA-La(OH)3/GO nanocomposites.The characterizations of worn surface showed that the OLA-La(OH)3/GO nanocomposites could form the metal oxide and graphene protective films effectively on the friction interface and thus increased the oil wettability of the worn surface,thereby resulting in an improved wear resistance.

Effect of Hyperbranched Poly(amine-ester) Grafted Nano-SiO_2 on Reinforcement and Toughness of PVC

Nano-SiO2 was modified using silane coupling agent （KH-550） and hyperbranched poly（amine-ester） respectively, and Poly（vinyl chloride） （PVC）/modified nano-SiO2 composites were made by melt-blending. The composites＇ structures andmechanical properties were characterized by transmission electron microscopy（TEM）, sanning electronic microscopy（SEM） and electronic universal testing machine. The results. show that nano-SiO2 grafted by hyperbranched poly （amine-ester） increases obviously in dispersion in PVC matrix, and mechanical properties of PVC are effectively improved. Moreover, it was found that mechanical properties of PVC/nano-SiO2 composites reach the best when weight percent of nano-SiO2 in PVC matrix is 1%. Compared with crude PVC, the tensile strength of hyperbranched poly （amine-ester） grafted nano-SiO2/ PVC composite increases by 24.68 % and its break elongation, flexural strength and impact strength increase by 15.73%, 4.07% and 1 841.84%, respectively. Moreover, the processing of the composites is improved.

The Influence of Yttrium Isopropoxide on the Mechanical Properties of SiC_w-reinforced AIN Ceramics

By using self-made metal-alkoxide yttrium isopropoxide as a sintering additive and disperser of whisker, the SiC whisker reinforced AIN ceramics was prepared. Its apparent density is 99.5 percent of the theoretical density; its flexural strength and fracture toughness are 681 MPa and 5.21 MPa·m1/2 respectively. Comparing the result with that by applying Y2O3 powder as a sintering additive, the flexural strength is increased by 25% and the fracture toughness is increased by 33% . The dispersity of whisker by increased yttrium isopropoxide is significantly better than that by Triton X-100.

Novel Method of Hyperbranched Polymer Modified Nano-SiO_2-Grafting Hyperbranched Poly(amide-ester) from Nano-SiO_2 by One-Step Polycondensation

A new method of surface chemical modification of nano-SiO2 is proposed in this paper. In the presence of catalyst, the active hydroxyl groups on the surface of nano-SiO2 reacted with AB2-type monomer （N, N-dihydroxyethyl-3-amino methyl propionate） by one-step polycondensation. And the product＇s Fourer transform infrared （FTIR） graphs and transmission electron microscopy（TEM） images proved that hyperbranched poly （amine-ester） was grafted on nano-SiO2 surface successfully. Results show that the modified nano-SiO2 exhibits excellent dispersion and stability in some solvents such as alcohol and chloroform.

Stability of partially deacetylated chitin nano-fiber dispersions mediated by protonic acids

Partially deacetylated chitin nano-fiber(DAChN)dispersions were prepared using mechanical treatment of partially deacetylated crab shellα-chitin under acidic conditions mediated by various protonic acids.The representative organic acids had a better efficiency in terms of mediating the nanofibrillation of chitin fibers in comparison to the inorganic acid(HCl).The DAChN dispersed in water at a pH of 3.5 mediated by gluconic acid exhibited the highest yield of nano-fibers(88.6%),followed by succinic,itaconic,and ascorbic acids with a nano-fiber yield of 79.9%,73.3%and 66.0%,respectively.The pH,conductivity,viscosity,and light transmittance of dispersions were assessed under different storage times.All of the tested DAChN dispersions were stable for at least 15 weeks at 4℃.

Nanolubricant additives: A review

Using nanoadditives in lubricants is one of the most effective ways to control friction and wear,which is of great significance for energy conservation,emission reduction,and environmental protection.With the scientific and technological development,great advances have been made in nanolubricant additives in the scientific research and industrial applications.This review summarizes the categories of nanolubricant additives and illustrates the tribological properties of these additives.Based on the component elements of nanomaterials,nanolubricant additives can be divided into three types:nanometal-based,nanocarbon-based,and nanocomposite-based additives.The dispersion stabilities of additives in lubricants are also discussed in the review systematically.Various affecting factors and effective dispersion methods have been investigated in detail.Moreover,the review summarizes the lubrication mechanisms of nanolubricant additives including tribofilm formation,micro-bearing effect,self-repair performance,and synergistic effect.In addition,the challenges and prospects of nanolubricant additives are proposed,which guides the design and synthesis of novel additives with significant lubrication and antiwear properties in the future.

Effects of Ce on catalytic combustion of methane over Pd-Pt/Al_2O_3 catalyst

Activity and stability of 1%Pd-0.2%Pt/Al2O3 and 1%Pd-0.2%Pt/0.6%Ce/Al2O3 catalysts prepared by impregnation method for catalytic combustion of methane in air were investigated. The catalysts before and after reaction were characterized by BET, CO chemisorption, XRD and XPS techniques. Results showed that the presence of Ce significantly increased the activity and thermal stability of the Pd-Pt/Al2O3 catalyst towards methane combustion, which could be attributed to more highly-dispersed active PdO particles over the Pd-Pt/Ce/Al2O3 catalyst surface as well as the retarded sintering of PdO and the maintained oxidized state of surface Pd during the combustion process in the presence of Ce.

Construction of highly stable selenium nanoparticles embedded in hollow nanofibers of polysaccharide and their antitumor activities

Nanotechnologies have been exploited to develop safe and effective medicines and pharmaceuticals.In the present study,a novel functional nanomedicine constructed from a bioactive polysaccharide and selenium nanoparficles （SeNPs） was developed.A highly-branched [3-（1→3）-D-glucan （AF1） with high anti-tumor activity was used to self-assemble hollow nanofibers with an apparent average diameter of 92 nm;Se nanopartides were synthesized via the reduction of sodium selenite.The results of light scattering,transmission electron microscopy,and X-ray diffraction demonstrated that the spherical SeNPs with a mean diameter of 46 nm were entrapped in the cavities of the AF1 hollow nanofibers through the formation of Se-O bonds between SeNPs and AF1,leading to the good dispersion and high stability in water for over 16 months.In vitro and in vivo assays indicated that the AF1-Se nanocomposite had higher anti-tumor activities against breast cancer.Furthermore,AF1-Se displayed a broad-spectrum inhibition against human cancers with low half maximal inhibitory concentration （IC50） values and low toxicity to normal cells.Particularly,the inhibition ratio of AF1-Se against MCF-7 cancer cells reached 75% at a concentration of 200 μg.mL-1 with 29 μM Se content,much higher than that by treatment with AF1 alone,suggesting a strong synergic effect and nano impact.Overall,we developed a method for increasing the stability,anti-tumor activity,and safety of SeNPs by wrapping with bioactive polysaccharides.

High-concentration dispersions of exfoliated MoS2 sheets stabilized by freeze-dried silk fibroin powder

Liquid-phase exfoliation （LPE） is an attractive method for the scaling-up of exfoliated MoS2 sheets compared to chemical vapor deposition and mechanical cleavage. However, the MoS2 nanosheet yield from LPE is too small for practical applications. We report a facile method for the scaling-up of exfoliated MoS2 nanosheets using freeze-dried silk fibroin powders. Compared to MoS2 dispersion in the absence of silk fibroin powder, sonicated MoS2 dispersions with silk fibroin powder （MoSJSilk dispersion） show noticeably higher exfoliated MoS2 nanosheet yields, with suspended MoS2 concentrations in MoS2/Silk dispersions sonicated for 2 and 5 h of 1.03 and 1.39 mg.mL-1, respectively. The MoS2 concentration in the MoS2/Silk dispersion after centrifugation above 10,000 rpm is more than four times that without the silk fibroin. The size of the dispersed silk fibroin is controlled by the change of centrifugation rate, showing the removal of silk fibroin above tens of micrometers in size after centrifugation at 2,000 rpm. Size-controlled silk fibroin biomolecules combined with MoS2 nanosheets are expected to increase the practical use of such materials in fields related to tissue engineering, biosensors and electrochemical electrodes. Atomic force microscopy and Raman spectroscopy provide the height of the MoS2 nanosheets spin-cast from MoS2/Silk dispersions, showing thicknesses of 3--6 nm. X-ray photoelectron spectroscopy and X-ray diffraction indicate that the outermost surface layer of the hydrophobic MoS2 crystals interact with oxygen-containing functional groups that exist in the hydrophobic part of silk fibroins. The amphiphilic properties of silk fibroin combined with the MoS2 nanosheets stabilize dispersions by enhancing solvent-material interactions. The large quantities of exfoliated MoS2 nanosheets suspended in the as-synthesized dispersions can be utilized for the fabrication of vapor and electrochemical devices requiring high MoS2 nanosheets contents.

Relationship between Crystal Structure of Inclusions and Formation of Acicular Ferrites

The formation mechanism of intragranular ferrites with acicular morphology was discussed.The ferrites were characterized by scanning electron microscopy.The results showed that the ferrites had an acicular structure with radial,symmetrical,and acicular laths,and that the inclusions were the nucleation sites of the intragranular acicular ferrites.Transmission electron microscopy（TEM）was used to characterize the inclusions.The results of TEM with energy dispersive spectroscopy and TEM-selected area electron diffraction indicated that the complex inclusions consisted of Ti-Al complex oxides and MnS.The jagged edges of the complex inclusions can be ascribed to the effects of the crystal structure.The stabilization energy U of the coordination polyhedron growth units varies with the type of connection according to the calculation results.A larger Ucorresponds to more stable growth units,which induces the preferentially oriented growth of inclusions,at which point acicular ferrites are formed.

Core/shell magnetite/copolymer composite nanoparticles enabling highly stable magnetorheological response

Magnetorheological fluids(MRFs)have been successfully used in a variety of smart control systems,but are still limited due to their relatively poor settling stability.Herein,a core/shell‐structured Fe_(3)O_(4)/copolymer composite nanoparticle is synthesized as a new candidate material for stimulus‐responsive MRFs to tackle the limitation of the long‐term dispersion stability.Aniline‐co‐diphenylamine copolymers(PANI‐co‐PDPA)are loaded onto the surface of Fe_(3)O_(4) nanoparticles,providing a lighter density and sufficient active interface for the dispersion of magnetic particles in the carrier medium.The features of the Fe_(3)O_(4)/copolymer composite nanoparticles,including morphology,compositional,and crystalline properties,are characterized.An MRF is prepared by suspending Fe_(3)O_(4)/copolymer composite nanoparticles in a nonmagnetic medium oil,and its rheological properties are assessed using a controlled shear rate test and dynamic oscillation tests using a rotational rheometer.Rheological models including the Bingham model and the Herschel–Bulkley model are fitted to the flow curves of the MRF.The obtained Fe_(3)O_(4)/copolymer composite shows soft‐magnetic properties,as well as greater density adaptability and higher stability,compared to Fe_(3)O_(4).Moreover,the sedimentation testing provides information about the dispersion stability characteristics of MRF and shows a good correlation with high‐stability magnetorheological(MR)response.The Fe_(3)O_(4)/copolymer‐based MRF with a tunable and instantaneous MR response is considered a promising material for smart control applications.

Preparation of stable colloidal suspensions of superdisintegrants via wet stirred media milling

Superdisintegrants are cross-linked polymers that can be used as dispersants for fast release of drug nanoparticles from nanocomposite microparticles during in vitro and in vivo dissolution. Currently avail- able superdisintegrant particles have average sizes of approximately 5-130 μm, which are too big for drug nanocomposite applications. Hence, production of stable superdisintegrant suspensions with less than 5 μm particles is desirable. Here, we explore the preparation of colloidal suspensions of anionic and nonionic superdisintegrants using a wet stirred media mill and assess their physical stability. Sodium starch glycolate （SSG） and crospovidone （CP） were selected as representative anionic and nonionic superdisintegrants, and hydroxypropyl cellulose （HPC） and sodium dodecyl sulfate （SDS） were used as a steric stabilizer and a wetting agent/stabilizer, respectively. Particle sizing, scanning electron microscopy, and zeta potential measurements were used to characterize the suspensions. Colloidal superdisintegrant suspensions were prepared reproducibly. The extensive particle breakage was attributed to the swelling-induced softening in water. SSG suspensions were stable even in the absence of stabilizers, whereas CP suspensions required HPC-SDS for minimizing particle aggregation. These findings were explained by the higher absolute （negative） zeta potential of the suspensions of the anionic superdisintegrant （SSG） as compared with those of the nonionic superdisintegrant （CP）.