Determination of Latex Particle Size Distributions by Fractional Creaming with Sodium Alginate

1961 ◽  
Vol 34 (2) ◽  
pp. 433-445 ◽  
Author(s):  
E. Schmidt ◽  
P. H. Biddison
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Sodium Alginate ◽  
Mass Distribution ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Size Distributions ◽  
Particle Size Distributions

Abstract Knowledge of mass distribution of particle sizes in latex is very important to the latex technologist. Therefore, it is desirable to have available a simple method for the determination of mass distribution of particle sizes. This paper presents a method, based on fractional creaming of latex with sodium alginate, which can be used in any laboratory without special equipment. The method is particularly advantageous for analyzing latexes of very wide particle size distributions. When analyzed with an electron microscope, these latexes require counting a very large number of particles. McGavack found that partial creaming of normal hevea latex with ammonium alginate gives concentrates of larger average particle size than the original latex. He found that the average particle size in the cream approaches that of the original latex as the amount of creaming agent is increased. In a previous paper from this laboratory, Schmidt and Kelsey demonstrated that the phenomenon of fractionation according to particle size with increasing amounts of creaming agent is applicable in a wide variety of anionic latex systems and in colloidal silica. Their results indicated also the existence of a quantitative relationship, independent of the nature of the dispersed particles, between the concentration of creaming agent and size of creamed particles. Maron confirmed fractionation with respect to particle size as a consequence of partial creaming with alginate. He showed that the mass average particle sizes of fractions, determined optically, cumulate to that of the original latex. Although the previous paper by Schmidt and Kelsey implied the basic concept of a method of determining particle size distribution by fractional creaming, it was not exploited at that time. In order to adapt the fractional creaming phenomenon to a quantitative method for particle size determination, we required a more precise knowledge of the relation between creaming agent concentration and size of particles creamed. It was proposed to establish this relationship with the aid of the electron microscope. Various factors influencing the creaming of latex, such as polymer concentration, electrolyte, soap content, and variability of the creaming agent, had to be considered in standardizing the creaming procedure.

Gas-phase particle size distributions and lead loss during spray pyrolysis of (Bi,Pb)–Sr–Ca–Cu–O

1995 ◽  
Vol 10 (7) ◽  
pp. 1644-1652 ◽  
Author(s):  
Abhijit S. Gurav ◽  
Toivo T. Kodas ◽  
Jorma Joutsensaari ◽  
Esko I. Kauppincn ◽  
Riitta Zilliacus
Keyword(s):  
Particle Size ◽  
Spray Pyrolysis ◽  
Gas Phase ◽  
Phase Particle ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Processing Temperature ◽  
Average Particle ◽  
Size Distributions ◽  
Particle Size Distributions

Gas-phase particle size distributions and lead loss were measured during formation of (Bi,Pb)-Sr-Ca-Cu-O and pure PbO particles by spray pyrolysis at different temperatures. A differential mobility analyzer (DMA) in conjunction with a condensation particle counter (CPC) was used to monitor the gas-phase particle size distributions, and a Berner-type low-pressure impactor was used to obtain mass size distributions and size-classified samples for chemical analysis. For (Bi,Pb)-Sr-Ca-Cu-O, as the processing temperature was raised from 200 to 700 °C, the number average particle size decreased due to metal nitrate decomposition, intraparticle reactions forming mixed-metal oxides and particle densification. The geometric number mean particle diameter was 0.12 μm at 200 °C and reduced to 0.08 and 0.07 μm, respectively, at 700 and 900 °C. When the reactor temperature was raised from 700 and 800 °C to 900 °C, a large number (∼107 no./cm3) of new ultrafine particles were formed from PbO vapor released from the particles and the reactor walls. Particles made at temperatures up to 700 °C maintained their initial stoichiometry over the whole range of particle sizes monitorcd; however, those made at 800 °C and above were heavily depleted in lead in the size range 0.5–5.0 μm. The evaporative losses of lead oxide from (Bi,Pb)-Sr-Ca-Cu-O particles were compared with the losses from PbO particles to gain insight into the pathways involved in lead loss and the role of intraparticle processes in controlling it.

Novel Precipitation Route to Silica Grain

1992 ◽  
Vol 271 ◽  
Author(s):  
Barbara Simms ◽  
Tom Gallo
Keyword(s):  
Particle Size ◽  
Acetic Acid ◽  
Aqueous Ammonia ◽  
Sol Gel ◽  
Average Particle ◽  
Particle Sizes ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Small Particles ◽  
High Degree

ABSTRACTWe describe a novel precipitation route to silica grain that lies in the interface between sol-gel and Stöber-type silica. The use of acetic acid as a catalyst for TEOS hydrolysis provides access to a precipitation window in which partially hydrolyzed TEOS and TEOS monomer, when reacted with aqueous ammonia, combine to form pumice-like silica particles in up to 90% yield as SlO2. Precipitated particles exhibit narrow particle size distributions that may be controlled for average particle sizes from 50µ to 400 µ. SEM micrographs show that the particles are agglomerates of small particles, which is consistent with the high degree of observed macroporosity.

Method of Calculating True Particle Size Distributions from Observed Sizes in a Thin Section

1998 ◽  
Vol 4 (2) ◽  
pp. 122-127 ◽  
Author(s):  
E. Bruce Nauman ◽  
Timothy J. Cavanaugh
Keyword(s):  
Particle Size ◽  
Thin Section ◽  
Previous Method ◽  
Spherical Particles ◽  
Average Particle ◽  
Particle Sizes ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Negative Particle ◽  
Transmission Microscopy

Particle size distributions obtained from a thin section are usually a skewed version of the true distribution. A previous method for determining the parent distribution was questionable because negative particle frequencies could be obtained. Here, we describe a method of determining parent distributions of spherical particles using a model with adjustable parameters. Our calculated distributions are somewhat broader than the distributions obtained with previous methods, but the average particle sizes are nearly identical. The newly developed model is applicable to any type of transmission microscopy.

scholarly journals Preparation of Polyetherimide Nanoparticles by a Droplet Evaporation-Assisted Thermally Induced Phase-Separation Method

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1548
Author(s):  
Peng Zhu ◽  
Huapeng Zhang ◽  
Hongwei Lu
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Phase Separation ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Droplet Evaporation ◽  
Average Particle ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Pei Nanoparticles

The droplet evaporation effect on the preparation of polyetherimide (PEI) nanoparticles by thermally induced phase separation (TIPS) was studied. PEI nanoparticles were prepared in two routes. In route I, the droplet evaporation process was carried out after TIPS. In route II, the droplet evaporation and TIPS processes were carried out simultaneously. The surface tension and shape parameters of samples were measured via a drop shape analyzer. The Z-average particle diameter of PEI nanoparticles in the PEI/dimethyl sulfoxide solution (DMSO) suspension at different time points was tested by dynamic light scattering, the data from which was used to determine the TIPS time of the PEI/DMSO solution. The natural properties of the products from both routes were studied by optical microscope, scanning electron microscope and transmission electron microscope. The results show that PEI nanoparticles prepared from route II are much smaller and more uniform than that prepared from route I. Circulation flows in the droplet evaporation were indirectly proved to suppress the growth of particles. At 30 °C, PEI solid nanoparticles with 193 nm average particle size, good uniformity, good separation and good roundness were obtained. Route I is less sensitive to temperature than route II. Samples in route I were still the accumulations of micro and nanoparticles until 40 °C instead of 30 °C in route II, although the particle size distribution was not uniform. In addition, a film structure would appear instead of particles when the evaporation temperature exceeds a certain value in both routes. This work will contribute to the preparation of polymer nanoparticles with small and uniform particle size by TIPS process from preformed polymers.

scholarly journals Sodium Alginate Nanoparticles of Isoniazid: Preparation and Evaluation

2019 ◽  
Vol 11 (06) ◽  
Author(s):  
Sumit Kumar ◽  
Dinesh Chandra Bhatt
Keyword(s):  
Particle Size ◽  
Sodium Alginate ◽  
Encapsulation Efficiency ◽  
Drug Loading ◽  
Average Particle Size ◽  
Average Particle ◽  
In Vitro Drug Release ◽  
Ionotropic Gelation ◽  
Preparation And Evaluation

Fabrication and evaluation of the Isoniazid loaded sodium alginate nanoparticles (NPs) was main objective of current investigation. These NPs were engineered using ionotropic gelation technique. The NPs fabricated, were evaluated for average particle size, encapsulation efficiency, drug loading, and FTIR spectroscopy along with in vitro drug release. The particle size, drug loading and encapsulation efficiency of fabricated nanoparticles were ranging from 230.7 to 532.1 nm, 5.88% to 11.37% and 30.29% to 59.70% respectively. Amongst all batches studied formulation F-8 showed the best sustained release of drug at the end of 24 hours.

Maximum-entropy method as a routine tool for determination of particle size distributions by small-angle scattering

2004 ◽  
Vol 37 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Dragomir Tatchev ◽  
Rainer Kranold
Keyword(s):  
Particle Size ◽  
Fourier Transform ◽  
Small Angle ◽  
Maximum Entropy Method ◽  
Entropy Method ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Angle Scattering ◽  
The Fourier Transform

Several aspects of the application of the maximum-entropy method (MEM) to the determination of particle size distributions by small-angle scattering (SAS) are discussed. The `historic' version of the MEM produces completely satisfying results. Limiting the data error from below (i.e.imposing a minimal relative error) is proposed as a solution of some convergence problems. The MEM is tested against the Fourier transform technique. The size distribution of Pb particles in an Al–Pb alloy is determined by the MEM and the Fourier transform technique. The size distributions obtained by transmission electron microscopy (TEM) and SAXS show partial agreement.

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