Inorganic Particle Size Research Articles

Facile fabrication method of nanocomposite pore filling ion exchange membrane: Impregnation method using dispersion solution of inorganic particles

Research on composite ion exchange membranes (IEMs) focuses on compensating the limitations of homogenous IEMs. The fabrication of nanocomposite IEMs is relatively complex, as the dispersion of inorganic substances within a polymer matrix must be considered. In this study, we propose a simple method for preparing nanocomposite IEMs by combining a porous substrate and dispersion solution with inorganic nanoparticles. The nanocomposite porous substrate with nanoparticles is prepared by impregnating a solution into a porous substrate, where the nanoparticles penetrate the nanosized pores of the substrates by capillary forces. Subsequently, nanocomposite pore-filling IEMs (PIEMs) are fabricated by impregnating an electrolyte solution into the substrate and photopolymerization. Impregnation applies to the manufacture of nanocomposite PIEMs, regardless of the type, surface conditions, and size of inorganic particles in dispersion. Through the sequential impregnation of dispersion solutions, single- and multi-component PIEMs containing more than one type of nanoparticle are manufactured. The increased interconnectivity of ion conduction channels in PIEMs by nanoparticles causes permselectivity improvement in nanocomposite PIEMs. However, compared to PIEMs without inorganic particles, the addition of inorganic particles results in a lower electrolyte polymer content in the PIEMs, leading to deterioration of the ion exchange capacity and resistance of nanocomposite PIEMs.

Dip Coating From Density Mismatching Mixture

Abstract Solid transfer technology from mixtures is gaining ever-increasing attention from materials scientists and production engineers due to their high potential in near-net-shaped production of cost-effective engineering components. Dip coating, a wet deposition method, is an effective and straightforward way of thin-film/layers formation. The dipping mixtures are often embedded with inorganic fillers, nanoparticles, or clusters (d < 30 nm) that produce a thin film ranging from nm to couple microns. An increase in the volume of solid transfer by the dipping process can open-up a novel three-dimensional near-net-shape production. However, adding a larger inorganic particle size (>1 μm) or adding a higher solid fraction will increase the solid transfer but may result in a multiphase heterogeneous mixture. In this work, the physical mechanism of an increased volume of solid transfer with a larger spherical particle size (>5 μm) is investigated. Polymer-based glue and evaporating solvent are mixed to construct the liquid carrier system (LCS) for large inorganic hard particles. Moderate volume fraction of inorganic particles (20% < ϕp < 50%) are added into the LCS solution as solid loading. Three levels of binder volume fraction are considered simultaneously to investigate the effect of the solid transfer. Cylindrical AISI 304 steel wire with dia 0.81 mm is used as the substrate for dipping and coating. The coating thickness, weight, and surface packing coverage by the particles are measured in our lab. The results presented the influence of volume fraction of inorganic particle and glue composition on the solid transfer from the heterogeneous mixture.

Synthesis and characterization PVA electro-spun nanofibers containing encapsulated vitamin C in chitosan microspheres

This paper reported vitamin C (VC) encapsulated chitosan (CS) microspheres cross-linked in the presence of two cross-linking agents, sodium tripolyphosphate (STPP) and Tween 80, for controlled release of VC. Furthermore, the effect of the crosslinking agent was described. The obtained micro and nanocapsules were evaluated by loading efficiency, scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and in vitro release studies. Encapsulation efficiency was calculated. FTIR and XRD revealed the dispersion and stability of VC after encapsulation in the CS matrix. Using Tween 80, as a crosslinking agent, encapsulation was completely done, which is related to the larger number of hydroxyl groups of Tween, causing the formation of extensive hydrogen bonding with CS and VC. The release of VC from these microspheres was sustained and affected by the volume of cross-linking agent added. Finally, the release of VC from STPP-chitosan and Tween-chitosan microspheres followed Fick’s law of diffusion. By loading encapsulated VC in PVA, electrospun nanofibers obtained without beading defect, also conductivity, and viscosity of PVA polymer solution were measured. SEM and EDX results indicated that inorganic particle size was of the nano-order with uniform distribution and dispersion and the release of VC from PVA nanofibers was characterized.

Determination and distribution of size of inorganic particles by spectral deconvolution of surface plasmon resonance.

Determination and distribution of size of inorganic particles by spectral deconvolution of surface plasmon resonance.

Properties of coarse particles in suspended particulate matter of the North Yellow Sea during summer

Fine particles in seawater commonly form large porous aggregates. Aggregate density and settling velocity determine the behavior of this suspended particulate matter (SPM) within the water column. However, few studies of aggregate particles over a continental shelf have been undertaken. In our case study, properties of aggregate particles, including size and composition, over the continental shelf of the North Yellow Sea were investigated. During a scientific cruise in July 2016, in situ effective particle size distributions of SPM at 10 stations were measured, while temperature and turbidity measurements and samples of water were obtained from surface, middle, and bottom layers. Dispersed and inorganic particle size distributions were determined in the laboratory. The in situ SPM was divided into (1) small particles ( 256 μm). Large particles and medium particles dominated the total volume concentrations (VCs) of in situ SPM. After dispersion, the VCs of medium particles decreased to low values (<0.1 μL/L). The VCs of large particles in the surface and middle layers also decreased markedly, although they had higher peak values (0.1–1 μL/L). This suggests that almost all in situ medium particles and some large particles were aggregated, while other large particles were single particles. Correlation analysis showed that primary particles <32 μm influenced the formation of these aggregates. Microscopic examination revealed that these aggregates consisted of both organic and inorganic fine particles, while large particles were mucus-bound organic aggregates or individual plankton. The vertical distribution of coarser particles was clearly related to water stratification. Generally, medium aggregate particles were dominant in SPM of the bottom layer. A thermocline blocked resuspension of fine material into upper layers, yielding low VCs of medium-sized aggregate particles in the surface layer. Abundant large biogenic particles were present in both surface and middle layers.

Thermal degradation of Pb(Zr0.53Ti0.47 )O3/poly(vinylidene fluoride) composites as a function of ceramic grain size and concentration

Poly(vinylidene fluoride)/Pb(Zr0.53Ti0.47)O3,([PVDF]1−x/[PZT]x) composites of volume fractions x and (0–3) type connectivity were prepared in the form of thin films. PZT powders with average grain sizes of 0.2, 0.84, and 2.35 μm in different volume fraction of PZT up to 40 % were mixed with the polymeric matrix. The influence of the inorganic particle size and its content on the thermal degradation properties of the composites was then investigated by means of thermo-gravimetric analysis. It is observed that filler size affects more than filler concentration the degradation temperature and activation energy of the polymer. In the same way and due to their larger specific area, smaller particles leave larger solid residuals after the polymer degradation. The polymer degradation mechanism is not significantly modified by the presence of the inorganic fillers. On the other hand, an inhibition effect occurs due to the presence of the fillers, affecting particularly the activation energy of the process.

Experimental and numerical analysis of the sound insulation property of wood plastic composites (WPCs) filled with precipitated CaCO3

Abstract The sound transmission loss (STL) of precipitated calcium carbonate (PCC)-filled wood plastic composite (WPC) was studied using a numerical analysis method based on the mass law and sound scattering theory. Several physical models for explaining sound wave transmission in WPC were established, and relevant STL equations were derived. The STL of WPC filled with different PCC weight ratios was analyzed using these models. The results showed that the STL of WPC increased with an increase in sound frequency and PCC weight ratio. The improvement of sound insulation was attributed to the mass increase, sound scattering enhancement by the fillers, and PCC weight ratio. The predicted results showed similar trends to the experimental data under the same processing conditions. It was concluded that the proposed models can be used to analyze the STL of filled WPC. Larger inorganic particle size led to higher STL, but its effect was not obvious at lower frequency ranges. Predicted STL increased with increased weight ratio of wood for the whole frequency range tested.

Influence of Inorganic Particle Size on Impact Properties of PP/Elastomer/SiO₂Ternary Composites

ポリプロピレン/エラストマー/フィラー複合材料について，力学特性とエラストマーおよびフィラー添加との関連を検討した。エラストマーとしてポリスチレン－block-ポリエチレンブテンーblock-ポリスチレントリブロック共重合体(SEBS)を用い，フィラーとして平均粒子径0.1～3.3μmの球状シリカ粒子を用いた。弾性率および引張降伏応力は，粒子径が小さくなるのにつれてやや向上した。SEBSの体積分率が0.12以下においては，添加するシリカの粒子径が小さくなるのにともなって，衝撃強度はゆるやかに向上した。一方,SEBSの体積分率が0.17以上においては，平均粒子径0.1～2.0μmのシリカ粒子の添加は，衝撃強度を顕著に向上させた。

Transparent Infrared-Emitting CeF3:Yb−Er Polymer Nanocomposites for Optical Applications

Bright infrared-emitting nanocomposites of unmodified CeF(3):Yb-Er with polymethyl-methacrylate (PMMA) and polystyrene (PS), which offer a vast range of potential applications, which include optical amplifiers, waveguides, laser materials, and implantable medical devices, were developed. For the optical application of these nanocomposites, it is critical to obtain highly transparent composites to minimize absorption and scattering losses. Preparation of transparent composites typically requires powder processing approaches that include sophisticated particle size control, deagglomeration, and dispersion stabilization methods leading to an increase in process complexity and processing steps. This work seeks to prepare transparent composites with high solids loading (>5 vol%) by matching the refractive index of the inorganic particle with low cost polymers like PMMA and PS, so as to circumvent the use of any complex processing techniques or particle surface modification. PS nanocomposites were found to exhibit better transparency than the PMMA nanocomposites, especially at high solids loading (>/=10 vol%). It was found that the optical transparency of PMMA nanocomposites was more significantly affected by the increase in solids loading and inorganic particle size because of the larger refractive index mismatch of the PMMA nanocomposites compared to that of PS nanocomposites. Rayleigh scattering theory was used to provide a theoretical estimate of the scattering losses in these ceramic-polymer nanocomposites.

Inorganic Particle Size and Content Effects on Tensile Strength of Polymer Composites

The influence of inorganic filler particle size and content on tensile strength of polymer composites was discussed in this paper. Based on an interfacial model between inclusion and matrix and the work by Turcsanyi et al., an expression of interfacial adhesion parameter B was proposed, and a new tensile strength equation considering particle diameter effect for polymer composites was derived. A polypropylene (PP) filled with diatomite was fabricated by means of a twin-screw extruder, and the tensile mechanical properties were measured at room temperature to identify the effects of the filler diameter and content on the tensile mechanical properties of these composites. It was found that the tensile strength of these composite systems decreased slightly with an increase of the filler diameter. This equation was initially verified by using these measured data of tensile strength of the PP/diatomite composites. The results show that the predictions were close to the measured data of tensile strength, and the maximum relative errors between them were within 10%.

Electrical strength in ramp voltage AC tests of LDPE and its nanocomposites with silica and fibrous and laminar silicates

AbstractThe electrical strength of a set of LDPE micro and nanocomposites with silica, laminar silicates and fibrous silicates has been studied. A significant 60% increase of the breakdown electrical field is shown by the microsized microdispersed LDPE/montmorillonite composites while only a 20% increase is obtained with a nanosized laminar silicate. Nanosized nanodispersed composites of the spherical silica and fibrous silicate with LDPE show a lower increase of the breakdown electrical field. The data point scatter in repeated tests is very high in the case of the microcomposites, indicating strong morphological heterogeneity, while it is very low in the nanocomposites. This implies that these nanocomposites are remarkably defect‐free as regards electrically “weak” sites. An analysis of the crystalline structure, semicrystalline morphology and inorganic particle size and distribution evidences the importance of the role played not only by the inorganic particles but also by the semicrystalline morphology in the final dielectric performance of the composite. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1301–1311, 2008

Preparation and characterization of magnetite/hydroxyapatite/chitosan nanocomposite by in situ compositing method

AbstractChitosan is an important kind of biomaterial that is widely used in medical applications. One of the key concerns about its use is the preparation of composites used for bone engineering. Aim of this study concerns the preparation of three‐dimensional nanocomposites having potential use in bone repair and regeneration. The magnetite/hydroxyapatite/chitosan nanocomposites were prepared via in situ compositing method by preparing precursor solutions and molds with chitosan membrane. These nanocomposites were characterized by chemical, spectroscopic, magnetic, and morphological methods. X‐ray diffraction analysis results demonstrate the formation of magnetite and hydroxyapatite in the chitosan matrix. FTIR analysis indicates that inorganic nanoparticles were chemically bound to the amino and hydroxyl groups in CS molecules. From TG/DTA data, it can be concluded that during preparation raw materials were almost perfectly incorporated into the nanocomposites, and the decrease in decomposition temperatures indicates the formation of chemical bonds between inorganic nanoparticles and chitosan molecules. TEM results show that the maximum size of inorganic particles in the magnetite/hydroxyapatite/chitosan nanocomposites was under 50 nm, and these particles were dispersed homogeneously in the chitosan matrix. From the magnetic measurement, it could be concluded that the nanocomposites were superparamagnetic, which is also the peculiarity of nanomagnetites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

A study on the preferable preparation method of SPEEK/BPO 4 composite membranes via an in situ sol–gel process

Sulfonated poly(ether ether ketone) (SPEEK)/boron phosphate (BPO 4) composite membranes for polymer electrolyte fuel cells (PEFCs) were prepared via an in situ sol–gel process in our previous study [P. Krishnan, J.-S. Park, C.-S. Kim, Preparation of proton-conducting sulfonated poly(ether ether ketone)/boron phosphate composite membranes by an in situ sol–gel process, J. Membr. Sci. 279 (2006) 220]. Proton conductivity of the composite membranes increased with increasing the amount of BPO 4 up to 40 wt.% due to the increasing BPO 4 particle size. In this study, the effect of several variables such as reaction time, reaction temperature and ionic form of solution-casting SPEEK polymers on the relationship between the size of inorganic particles and proton conductivity of the membranes was investigated for the preparation of SPEEK/BPO 4 composite membranes. The composite membranes were characterized using FT-IR, SEM, DSC, TGA and proton conductivity. Among the variables, reaction time and reaction temperature were not dependent on the proton conductivity and size of BPO 4 in the in situ sol–gel process. However, the ionic form of solution-casting polymers for the composite membranes significantly influenced the size of BPO 4 particles. At the same amount of BPO 4 in the composite membranes, the composite membrane using H +-form polymer made the BPO 4 particle size five to six times higher than that using Na +-form polymer. Water uptake of the former composite membrane (in particular, an amount of freezable water) was higher than the latter due to the bigger size of BPO 4, and the proton conductivity of the former composite membrane increased. As a result, it can be recommended that the preparation of the composite membranes using H +-form polymer is preferable via the in situ sol–gel process.

Food acquisition responses of the suspension-feeding bivalve Placopecten magellanicus to the flocculation and settlement of a phytoplankton bloom

In situ technologies were employed to monitor suspended particle flocculation and floc settlement and utilization by a cohort of sea scallops ( Placopecten magellanicus) during the 2000 spring phytoplankton bloom in Bedford Basin, Nova Scotia, Canada. The objectives were to determine the effect of bloom flocculation and settling on food acquisition and utilization by scallops, and to assess the potential role of flocculation in enhancing the bioavailability of trophic resources and particle-reactive contaminants to bivalve filter feeders. The development and flocculation of the phytoplankton bloom were monitored within the surface layer (10 m depth) by in vivo chlorophyll fluorescence and silhouette camera observations. Sedimentation rate, seston abundance and composition, and sea scallop functional responses were monitored at 20 m depth (below the bloom) to provide insight into the potential forcing of feeding and digestion processes by changes in the abundance, composition and properties of the ambient food supply. The bloom began in mid-March and median floc diameter at 10 m depth increased rapidly from 200 μm to greater than 400 μm between 21 and 28 March. Flocs were observed to be abundant in the surface layer up to 4 April. Daily vertical particle flux was high during the last week of March and declined to near zero by 1 April. Clearance rates of scallops held at 20 m depth were relatively high (average ± S.D.; 11.7 ± 4.0 L h − 1 ) during the period of bloom settlement and declined rapidly to low levels (0.4 ± 0.9 L h − 1 ) after 31 March. Average absorption efficiency also declined (0.88 ± 0.01 to 0.78 ± 0.05) after bloom settlement. Daily biodeposition rates by scallops were poorly correlated with temporal variations in the quantity (total particulate matter and chlorophyll a concentration) or quality (organic content) of seston available to the scallops, but were significantly correlated with sedimentation rate. Comparison of disaggregated inorganic particle size distributions for suspended particulate matter, settled particles, and scallop feces indicated that fine-grained particles (1 to 4 μm) were effectively ingested by sea scallops—an indication of whole floc ingestion. The settlement of flocs produced during the spring bloom appears to be important in regulating this species physiological energetics and for enhancing the bioavailablility of fine particles (including picoplankton) and particle-reactive contaminants.

A three dimensional model of Cryptosporidium dynamics in lakes and reservoirs: A new tool for risk management

A model of Cryptosporidium oocyst dynamics for lakes and reservoirs is presented. The model consists of a module that simulates oocyst inactivation, resuspension, settling and aggregation onto particles. This module was coupled to the three‐dimensional Estuary Lake and Coastal Ocean Model (ELCOM), which was used to simulate lake hydrodynamics in addition to oocyst advection and turbulent diffusion. A field experiment that tracked the passage of a flood inflow throughout Myponga Reservoir, South Australia, was used to validate the coupled model. The model accurately captured the thermal dynamics, and the spatial and temporal distribution of different inorganic particle size classes and oocysts. The model and data indicate that oocysts do not readily attach to inorganic particles as other researchers have suggested but settle as free‐floating oocysts according to Stoke's sedimentation dynamics. The reduction in oocysts between the inflow and the offtake due to settling is therefore not as significant as previously thought. The potential for inactivation was also found to be small relative to the timescales for transport. The model is a useful tool to examine oocyst dynamics in lakes and reservoirs, to consider risk management assessments of different scenarios, and to assess the effectiveness of different sampling strategies.

Novel Polyimide/Silica Nanohybrids from Water Glass

Polyimide/silica hybrid materials were prepared via a novel sol-gel route using silicic acid oligomer (SAO) extracted from water glass. The decomposition temperatures of the hybrid samples were higher than pure polyimide. The transparency of the hybrid films could be maintained at up to 40 wt.-% silica content with the addition of γ-aminopropyltriethoxysilane (APTES). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results confirmed the formation and dispersion of nanometer-scale size of inorganic particles within polyimide matrix with APTES. The coefficients of thermal expansion (CTEs) of the hybrid films were lower than pure polyimide and decreased with the increasing content of silica.

In situ feeding and absorption responses of sea scallops Placopecten magellanicus (Gmelin) to storm-induced changes in the quantity and composition of the seston

Time-series of hourly clearance, ingestion and absorption rates and absorption efficiency were measured over 48 h for adult sea scallops ( Placopecten magellanicus) held in situ in a coastal embayment in Nova Scotia, Canada, during a wind-induced resuspension event. Temporal variations in oceanographic variables, and seston quantity and composition (organic matter, organic carbon, nitrogen, chlorophyll a, and inorganic particle size spectra) were monitored during the study with moored instruments and hourly water sampling. Resuspension of bottom materials during the storm resulted in large changes in the amount (1 to 30 mg l −1 total particulate matter) and nutritional quality (25 to 50% organic content) of seston. High sedimentation rates after the storm were accelerated by flocculation, resulting in the rapid settling of resuspended particles and an increase in seston quality. Observed short-term (hourly) fluctuations in clearance rate were not related to storm- or tide-induced changes in seston characteristics but were directly related to flow velocity. Significantly lower clearance rates were observed at relatively low (<4 cm s −1) and high (>9 cm s −1) flow speeds. The overall reduction in ingestion rates after the storm resulted from decreased food availability. Hourly absorption efficiency (AE) measurements were closely related to seston quality (total organic, organic C and N content) and AE declined exponentially with decreasing seston quality. Reductions in AE during the resuspension event were offset by the increased ingestion rate, resulting in no significant changes in absorption rates for organic matter, C, or N over the sampling period. As the low food quality of the resuspended matter was balanced by increased availability, any physiological regulation of food acquisition (i.e. clearance rate regulation) would have been irrelevant to maintaining food intake constant.

Particle size selectivity and resource partitioning in five species of Thalassinidea (Crustacea:Decapoda)

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 169:243-250 (1998) - doi:10.3354/meps169243 Particle size selectivity and resource partitioning in five species of Thalassinidea (Crustacea: Decapoda) Eunice H. Pinn, R. James A. Atkinson*, Andrew Rogerson** University Marine Biological Station, Millport, Isle of Cumbrae, KA28 0EG, United Kingdom *Addressee for correspondence. E-mail: r.j.a.atkinson@udcf.gla.ac.uk **Present address: Department of Chemistry and Chemical Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota 57701, USA ABSTRACT: Particle selectivity was examined in Calocaris macandreae, Callianassa subterranea, Jaxea nocturna, Upogebia deltaura and U. stellata by comparing the inorganic particle size range within the gut with that from their respective environments. C. subterranea and C. macandreae are both deposit feeders, whilst J. nocturna is a re- suspension feeder, i.e. this shrimp flicks up deposited material ahead of the mouthparts and suspension feeds. U. deltaura and U. stellata are both predominantly suspension feeders. Particle size selectivity was not observed for either C. macandreae or J. nocturna. When the particle size range of the sediment taken from the upogebiid site was compared with that of the gut, particle selectivity was observed for both species. When particle size distribution from the gut was compared to that of the water column, however, no such evidence of particle selectivity was noted. For C. subterranea, no evidence of particle selectivity was observed in the specimens taken from a very fine muddy sediment. However, those taken from a sandier site showed clear evidence of particle selectivity. Interspecific and intraspecific particle size selection is discussed in relation to resource partitioning. KEY WORDS: Callianassa · Calocaris · Upogebia · Resource utilization Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 169. Publication date: August 06, 1998 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1998 Inter-Research.

Application of a permeant/polymer diffusional model to the desorption of polychlorinated biphenyls from Hudson River sediments

The desorption of polychlorinated biphenyls (PCBs) from Hudson River sediments was examined using XAD-4 resin as a PCB adsorbent. Both a rapidly desorbing labile component and a more slowly desorbing resistant component were observed. The fraction of PCBs in the resistant component was found to be a function of PCB concentration and total organic carbon in the sediment, independent of inorganic particle size. Milling the sediment had no effect on PCB desorption, while pretreatment of the sediment using heat (with and without caustic addition) enhanced the rate ofdesorption and significantly decreased the resistant fraction. We propose that the labile and resistant fractions arise from disparate diffusional rates of PCBs from the swollen and condensed phases of the sediment organic matter

Drop stabilisation by inorganic solids in suspension polymerisation: Effect of inorganic particle size using a wax model

AbstractInorganic solids can be used for drop stabilisation in suspension polymerisation and, in some cases, the particle size can affect the drop stability significantly. Three theoretical models, each based on different theories for this drop stabilisation by inorganic solids, have been formulated. Experiments have been carried out using a wax model. These experiments were similar to those described previously [Brooks, B. W., Bygate. F. &amp; Lane, A. C, Brit. Polym. J., 20 (1988) 19‐24; Brooks, B. W., Trans. I. Chem. E., 57 (1979) 210‐12]. Particulate calcium phosphate, in different sizes, was used as the stabiliser. The theoretical models have been compared with the experimental results and it was found that two of the models bore some resemblance to the experimental results.