BaSO4 Nanoparticles Research Articles

In Situ synthesis of poly(styrene-butylacrylate-acrylic acid) latex/barium sulfate nanocomposite and evaluation of their film properties

Barium sulfate nanocrystals of average 40 nm sizes were prepared by the micellar solution spray process. The influences of atomized impingement flow on nanoparticle formation and stabilization were inspected on the basis of Fourier transform infrared (FTIR), X-ray diffraction, and transmission electron microscopy analysis. Poly(styrene–butylacrylate–acrylic acid) (PSBA) nanocomposites were synthesized by in situ copolymerization in the presence of 0.5–2.5% BaSO4 nanoparticles. FTIR and atomic force microscopy analysis confirmed the uniform dispersion of 2% or less nano-BaSO4 within the PSBA matrix. The strength of interfacial adhesion between the nanoparticle and copolymer was examined on the basis of hydroscopicity, differential scanning calorimetry, thermogravimetric analysis, and universal testing machine analysis of nanocomposite film. The glass transition and thermal decomposition temperatures of PSBA latex were shifted toward higher temperatures by the restriction of nano-BaSO4 on its segmental and long-range chain mobility. The well-dispersed nano-BaSO4, with a larger fraction of immobilized copolymer on the pigment surface, improves the scratch and abrasion resistance, decreases the water uptake, and increases the tensile strength and elongation at break of the latex film within the specific loading. Thus, fabricating the PSBA/BaSO4 nanocomposite presents an effective approach for development of latex coatings with enhanced performance. POLYM. COMPOS., 34:1670–1681, 2013. © 2013 Society of Plastics Engineers

Process intensification of BaSO4 nanoparticle preparation with agitation of microbubbles

This study presents a novel technique for the controllable preparation of BaSO4 nanoparticles via the introduction of microbubbles into the reaction system. A high-concentration system based on barite industry was used, with saturated aqueous Na2SO4 and BaS solutions as the reactants. Microbubbles were generated by a membrane dispersion microreactor. The mixing performance was characterized using parallel competing reactions. The effects of various operation parameters on the nanoparticles were determined, and the reaction conditions were optimized. The results showed that the mixing performance could be improved by introducing microbubbles. The BaSO4 nanoparticles were controllably prepared, with a relatively narrow size distribution. The average particle size could likewise be reduced to approximately 40nm. A dimensionless micromixing scale of the microbubble flow was defined, and a model for predicting the BaSO4 particle size was proposed. The calculated results were consistent with the experimental data.

Roles of polyacrylate dispersant in the synthesis of well-dispersed BaSO4 nanoparticles by simple precipitation

Well-dispersed BaSO4 nanoparticles were synthesized in the presence of sodium polyacrylate (PAAS) by a simple precipitation method, with BaCl2 and (NH4)2SO4 as reactants. The different roles performed by PAAS in the synthesis of BaSO4 nanoparticles were investigated using X-ray diffractometry, Fourier transform infrared spectroscopy, and transmission electron microscopy. The results indicate that the as-synthesized BaSO4 nanoparticles were spheres with an average diameter of 30nm and that their surfaces were affected by the PAAS. Under a typical procedure employed, PAAS reacted with BaCl2 to yield an intermediate, serving as a control releasing agent and separating the nucleation and crystal growth processes of the BaSO4 nuclei. During formation of the BaSO4 nanospheres, the intermediate slowly dissolved and released barium and polyacrylate ions, inhibiting the growth and aggregation of newly formed BaSO4 seeds and resulting in particles of narrow diameter distribution and improved dispersibility. Moreover, these polyacrylate ions further modified the surfaces of the BaSO4 nanoparticles.

Study on the stability and microstructural properties of barium sulfate nanoparticles produced by nanomilling

Barium sulfate nanoparticles were produced by nanomilling in stirred media mill using sodium salt of polyacrylic acid (PAA-Na) as a dispersant. The particles sizes of the ground product obtained in the grinding mill were determined by dynamic light scattering (DLS), Brunauer–Emmet–Teller (BET) nitrogen gas adsorption method, and transmission electron microscopy (TEM). The mean particle size calculated with various methods yielded different values due to the different characterization techniques. The stability of BaSO4 nanoparticles produced was analyzed by zeta potential measurement and Turbiscan. The stability of barium sulfate nanoparticles was high in presence of dispersant PAA-Na and higher pH values. Further, the changes in microstructural properties, caused by wet grinding and adsorption of PAA-Na on BaSO4 nanoparticles, were studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The surface activation and amorphization of BaSO4 nanoparticles were observed due to increased stresses exerted on the particles during wet grinding.

Preparation of Barium Sulfate Nanoparticles in an Interdigital Channel Configuration Micromixer SIMM-V2

BaSO4 nanoparticles were synthesized by precipitation of Na2SO4 and BaCl2 at their concentrations close to their saturation concentrations in a commercially available micromixer, SIMM-V2. The particle size of BaSO4 was dependent on the flow rate at the saturation concentrations, exhibiting a Z-type change with increasing the flow rate. The average particle size of BaSO4 particles could be adjusted by decreasing the Na2SO4 concentration. Decreasing the molar ratio R to less than 1 resulted in agglomerated round BaSO4 particles, while dispersible rod-like ones were produced when R = 1.2–1.8. The wastewater separated from each synthesis solution could be reused to prepare the BaCl2 solution, resulting in a slight increase in the mean particle size and broadened particle size distribution after eight cycles. The optimized preparation process could produce 2 kg/h of BaSO4 nanoparticles with a mean particle size of 28 nm with a narrow particle size distribution.

The Spinning Disk Reactor for Polymers and Nanoparticles

AbstractThe preparation of reactive polyurethanes, the photopolymerization, and copolymerization of acrylates in emulsion as well as solution and the precipitation and reactive precipitation to prepare BaSO4 and silver nanoparticles, respectively, employing a spinning disk reactor (SDR) are summarized. The advantages of an SDR (excellent mass and heat transfer, minimal energy, and material usage, easy scale up as well as flexibility) are discussed. Where experiments are described comparing the SDR with traditional batch processes, known, optimized industrial batch processes are chosen. In all cases, the SDR could be shown to yield equivalent product quality while having procedural advantages. magnified image

Controlled in situ synthesis of surface functionalized BaSO4 nanoparticles for improved bone cement reinforcement

Controlled in situ synthesis of surface functionalized BaSO4 nanoparticles is achieved by using a difunctional molecule to modulate the growth of nanoparticles coupled with in situ generation of SO4 2- under mild conditions. Such BaSO4 nanoparticles with surface vinyl groups reinforce the PMMA bone cement better than conventional BaSO4 particles.

HIGH DISPERSION BARIUM SULFATE NANOPARTICLES PREPARED WITH DODECYL BENZENE SULFONIC ACID

Production of nanoparticles by precipitation is a relatively simple process but the control of product particle size distribution is difficult. In this paper, nanosize barium sulfate ( BaSO 4) particles are prepared with dodecyl benzene sulfonic acid (DBSA) in ethanol–water reaction system at room temperature. The BaSO4 nanoparticles are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), powder X-ray diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TGA), respectively. The results indicated that the average diameter of spherical BaSO4 is about 46 nm modified with 5 wt.% DBSA, which have good dispersion in the presence of a certain concentration NH3 ⋅ H2O . It suggests that the high dispersion is attributed to presence of a thin layer of barium alkyl sulfate, which is formed and coated onto the surface of BaSO4 particles during the reaction process. The thin films on the surface of the BaSO4 effectively modified the surface and properties, which also control the particle size and morphology.

THE PERFORMANCE OF BARIUM SULFATE NANOPARTICLES/POLYPROPYLENE HYBRID MULTIFILAMENT

Nanosize barium sulfate ( BaSO 4) particles prepared with dodecyl benzene sulfonic acid (DBSA) in ethanol–water reaction system are used to prepare BaSO4 /polypropylene (PP) nanocomposites by melt mixing method. It is then made into hybrid fibers by melt spinning and subsequent drawing with different ratios. The hybrid fibers are characterized by rheology, morphology, thermal stability and mechanical properties, respectively. The results indicate that the DBSA-modified BaSO4 can improve the spinnability of BaSO4 /PP hybrid multifilament even at high BaSO4 nanoparticles concentration. DBSA can be used as compatibilizer to enhance the interface interaction of BaSO4 /PP nanocomposites, because DBSA contains both hydrophobicity long alkyl chain and hydrophilic sulfonic group. Therefore, it can improve the performances of BaSO4 /PP hybrid multifilament.

Rheological investigation of polyamide 6 TiO2‐ and BaSO4‐nanocomposites

AbstractCommercially available TiO2 and BaSO4 nanoparticles were incorporated in polyamide 6 (PA 6) via twin screw extrusion. The primary particle size of nanoparticles was 15 nm and 20 nm. The compounds were manufactured via multiple extrusion and dilution processing steps. The dispersion of the nanoparticles in the matrix was investigated by scanning electron microscopy and image analysis, micro‐tomography, and transmission electron microscopy. The rheological properties were determined via plate–plate‐rheometer. It was found that for TiO2 fillers a threefold extrusion process is sufficient to realize a dispersion index of 94.4%. BaSO4 fillers were hardly dispersible, ending up with a maximum dispersion index of 71%. Deagglomeration does not lead to a change in rheological properties but the number of extrusion steps decreases the rheological properties. A good particle‐matrix interaction leads to higher moduli and viscosity. The remaining agglomerates seem to act as defects decreasing the energy absorption of the respective compounds. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Microfluidic one-step fabrication of radiopaque alginate microgels with in situ synthesized barium sulfate nanoparticles

In this work, we report a new strategy to fabricate monodispersed radiopaque alginate (Ba-alginate) microgels by a one-step microfluidic method. Alginate droplets containing sulfate ions are first formed by a flow focusing microfluidic setup. These alginate droplets are subsequently solidified by barium ions in a collection bath. During the solidification process, excessive barium ions in the collection bath also react with sulfate ions in the alginate droplet, resulting in barium sulfate (BaSO(4)) nanoparticles in situ synthesized (acting as radiopaque imaging agents) within the Ba-alginate microgels. Scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX) illustrate that 800 nm BaSO(4) nanoparticles are uniformly distributed inside the 30 μm Ba-alginate microgels, with 62 wt% of elemental barium (Ba). In addition, X-ray diffraction (XRD) measurements indicate that the BaSO(4) nanoparticles consist of 10 nm in situ synthesized BaSO(4) crystallites. The alginate microgels act as a soft and porous template to prevent the precipitation and aggregation of BaSO(4) nanoparticles. The Ba-alginate microgels are also visible under X-ray radiation. The facile route to fabricate alginate microgels as radiopaque embolic materials is of particular importance for endovascular embolization and localized diagnostic imaging applications. Similar approaches can also be adopted for synthesizing other inorganic nanoparticles in microgels.

Multiple extrusion and dilution of nanocomposites and their effect on the mechanical properties

Commercially available TiO2 and BaSO4 nanoparticles were incorporated in polyamide 6 (PA 6) via twin screw extrusion. The primary particle size of these two nanoparticles was 15 nm and 20 nm, respectively. The compounds were manufactured via multiple extrusion and dilution processing steps. The dispersion of the nanoparticles in the matrix was investigated by scanning electron microscopy and image analysis. The mechanical properties were determined via tensile and bending tests. The toughness was investigated by the Charpy V-notch impact strength test. It was found that for TiO2 fillers a threefold extrusion process is sufficient to realize a dispersion index of 94.4%. BaSO4 fillers were hardly dispersible, ending up with a maximum dispersion index of 71%. Tensile and bending properties are maintained constant, or can be improved with the number of performed extrusion steps. Despite good deagglomeration, impact strength at low concentrations was not improved in case of TiO2, which is probably due to remaining microagglomerates.

Preparation of Flower-Shaped Barium Sulfate Nanoparticles in the Presence of DTAB

The effect of various concentration of dodecyltrimethylammonium bromide (DTAB) on the precipitation of barium sulfate (BaSO4) was investigated. Flower-shaped BaSO4 nanoparticles were synthesized in the presence of DTAB. Scanning electron microscope (SEM) and x-ray diffraction (XRD) were used to characterize the morphologies and structures of BaSO4 crystals. On the basis of the characterizations, a possible formation mechanism was proposed.

Synthesis of Baso<sub>4</sub> Nanoparticles by Precipitation Method Using Polycarboxylate as a Modifier

Problem statement: Barium Sulfate (BaSO4) is suitable for many applications because of its whiteness, inertness and high specific gravity. Approach: Nanoparticles of barium sulphate (BaSO4) have been synthesized from barium nitrate by precipitation method in the presence of water soluble organic polycarboxylic polymer as a modifying agent. Transmission electron microscopy, Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray powder diffractometry were used to characterize the products as well as laser grainmeter. Results: The results indicate that spherical BaSO4 nanoparticles are obtained with poor crystalline and diameters ranging from 30-35 nm. Conclusion: The organic polycarboxylate shows as good modifier agent. So, this method can be employed to synthesize higher yield of BaSO4 nanoparticles.

Isothermal crystallization kinetics and melting behavior of modified high‐density polyethylene/barium sulfate nanocomposites

AbstractThe melting/crystallization behavior and isothermal crystallization kinetics of high‐density polyethylene (HDPE)/barium sulfate (BaSO4) nanocomposites were studied with differential scanning calorimetry (DSC). The isothermal crystallization kinetics of the neat HDPE and nanocomposites was described with the Avrami equation. For neat HDPE and HDPE/BaSO4 nanocomposites, the values of n ranges from 1.7 to 2.0. Values of the Avrami exponent indicated that crystallization nucleation of the nanocomposites is two‐dimensional diffusion‐controlled crystal growth. The multiple melting behaviors were found on DSC scan after isothermal crystallization process. The multiple endotherms could be attributed to melting of the recrystallized materials or the secondary lamellae caused during different crystallization processes. Adding the BaSO4 nanoparticles increased the equilibrium melting temperature of HDPE in the nanocomposites. Surface free energy of HDPE chain folding for crystallization of HDPE/BaSO4 nanocomposites was lower than that of neat HDPE, confirming the heterogeneous nucleation effect of BaSO4. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers

Effect of Barium Sulfate Nanoparticles on Mechanical Properties and Crystallization Behaviour of HDPE

High density polyethylene (HDPE)-based composites were prepared by blending HDPE with BaSO4 nanoparticles, which had been treated with sodium stearate. Variations in crystallization behaviour, mechanical properties, storage modulus and damping parameter (tan d) with the addition of BaSO4 nanoparticles were investigated by SEM, XRD, DSC, DMA, etc. The crystallization rate steadily increased with the content of BaSO4 nanoparticles because of these nanoparticles acting as a heterogeneous nucleation agent. The impact strength of HDPE first increased and then decreased with increasing the content of BaSO4 nanoparticles. The maximum impact strength of HDPE nanocomposites was achieved at a weight ratio of BaSO4/HDPE = 1/100. However, the tensile yield stress gradually increased with the content of BaSO4 nanoparticles. Dynamic mechanical analysis data showed an increase in the storage modulus of composites with increasing content of BaSO4 nanoparticles. The tan d value of nanocomposites decreased in comparison to the neat HDPE. It was demonstrated that the BaSO4 nanoparticles treated with sodium stearate had stronger effective interface interaction with HDPE matrix and adding 1.0 wt.% modified BaSO4 nanoparticles could effectively reinforce HDPE matrix.

Hierarchically Nanostructured Barium Sulfate Fibers

BaSO(4) nanostructures with controlled morphologies were successfully produced via one-step process through precipitation of BaSO(4) in aqueous and organic media. The synthesis is carried out by mixing solutions of BaCl(2) and Na(2)SO(4) in presence of EDTA (disodium ethylenediaminetetraacetic acid) at room temperature. The influence of the reaction conditions such as initial reactants concentration, pH, EDTA/[Ba(2+)] ratio and aging on the BaSO(4) nanoparticles organization is studied. Using EDTA in aqueous media, spherical secondary particles of 500 nm diameter are obtained, which are formed by 4 nm size primary particles. With dimethyl sulfoxide and small amounts of water (5%) and EDTA, the aging process allows the production of long homogeneous fibers, related to hierarchical organization of BaSO(4) nanoparticles. Direct observation of self-assembling of primary particles by HRTEM allows proposing a mechanism for fiber formation, which is based on multipolar attractions that lead to a brick-by-brick organization along a preferential orientation. Results evidence the role of EDTA as controlling agent of the morphology and primary and secondary mean particle size.

Liquid–liquid two‐phase flow in pore array microstructured devices for scaling‐up of nanoparticle preparation

AbstractNanoparticles have been produced by a T‐junction microchannel device in our previous work (Li et al., Langmuir. 2008;24:4194‐4199). As a scaling‐up strategy, pore array microstructured devices were designed to prepare nanoparticles in this article. H2SO4 and BaCl2, respectively, in two phases to form BaSO4 nanoparticles was used as a test system. The characteristics of a well controlled liquid–liquid two‐phase flow in the pore array microstructured devices were presented. Nanoparticles with small size and good dispersibility were produced through drop or disk flows in the microstructured devices. The influence of mass transfer and chemical reaction on interfacial tension and flow patterns was discussed based on the experiments. Meanwhile, the effect of the two phase flow patterns on the nanoparticle size was discussed. It was found that the increase of the amount of mass transfer and chemical reaction could change the flow patterns from disk flow to drop flow. The droplet diameter could be changed in a wide range. Flow patterns could be distinguished based on the measured interfacial tension in different concentrations. The prepared nanoparticles were ranged from 10 nm to 30 nm. Apparently the particle size was decreased with the increase of the droplet size in both the drop flow region and the disk flow region whereas it had a reverse trend in the transition region. © 2009 American Institute of Chemical Engineers AIChE J, 2009

Reduced discrete population balance model for precipitation of barium sulfate nanoparticles in non-ionic microemulsions

A discrete population balance model is formulated in order to analyze the precipitation process of barium sulfate nanoparticles taking place in the droplets of a water-in-oil microemulsion. The model accounts for the distribution of reactants over the droplet population in terms of discrete numbers of the reacting ionic species (Ba2+, SO42−), as well as for the nucleation and growth of solid particles in terms of discrete BaSO4-molecular units. The introduction of physically motivated assumptions leads to a considerable reduction of complexity of the population balance model. The kinetic parameters for nucleation and growth are estimated by fitting of simulated particle size distributions to recently published experimental data by Niemann et al. [B. Niemann, P. Veit, K. Sundmacher, Nanoparticle precipitation in reverse microemulsions: particle formation dynamics and tailoring of particle size distributions, Langmuir 24 (1), 2008, 4320–4328] and Adityawarman et al. [D. Adityawarman, A. Voigt, P. Veit, K. Sundmacher, Precipitation of BaSO4 nanoparticles in a non-ionic microemulsion: identification of suitable control parameters, Chem. Eng. Sci. 60 (12), 2005, 3373–3381]. The obtained parameter values support the conclusion that particle nucleation follows a heterogeneous mechanism and that the nanostructure of the microemulsion has a significant effect on the particle growth mechanism. The considered microemulsion-assisted precipitation process allows the generation of nanoparticle morphologies which are not attainable by classical bulk phase precipitation processes.

Novel Method for the Preparation of Mesoporous BaSO4Material with Thermal Stability by Spray Pyrolysis

Spray pyrolysis has been found as an excellent method for the preparation of mesoporous barium sulfate at higher temperature. Ethylene glycol, a reducing agent, and solvents had good inhibition effect for the preparation of <TEX>$BaSO_4$</TEX> nano particles. The <TEX>$BaSO_4$</TEX> solution was sprayed at 500 & 800 <TEX>${^{\circ}C}$</TEX> using different solvents such as methanol, ethanol, propanol and n-butyl alcohol. <TEX>$N_2$</TEX> adsorption-desorption isotherm revealed that <TEX>$BaSO_4$</TEX> is micropore free, possessing narrow mesopores size distribution and high BET surface areas of 72.52 <TEX>$m^2\;g^{-1}$</TEX> at 800 <TEX>${^{\circ}C}$</TEX> using propanol as an additive. Scanning electron microscopy (SEM) indicates that the morphology of <TEX>$BaSO_4$</TEX> nano material shows uniform shell like particles. Transmission electron microscopy (TEM) proved that the resulting BaSO4 nano particles were uniform in size and the average particle size was 4-8 nm. The surface functionality and ethylene glycol peaks were assessed by Fourier transform infrared resonance (FTIR) spectroscopy. Low intensity ethylene glycol specific absorption peak was observed in propanol which proved that propanol had good inhibition effect on the structural morphology of nano particles.