The Formation and Characterization of Poly (p-phenylene benzobisoxazole) Pulps via Stirred Solutions

2015 ◽  
Vol 1120-1121 ◽  
pp. 620-623
Author(s):  
Rong Biao Liu ◽  
Xin Xin Li ◽  
Jun Qian ◽  
Zhe Wen Han
Keyword(s):  
Specific Surface ◽  
Electron Micrographs ◽  
Methanesulfonic Acid ◽  
Scanning Electron Micrographs ◽  
Short Fibers ◽  
Surface Areas ◽  
Stirring Time ◽  
Specific Surface Areas ◽  
Scanning Electron

PBO (p-phenylene benzobisoxazole) short fibers, attached fine fibrils that are called PBO pulp, may precipitate directly from stirred PBO/methanesulfonic acid (MSA) solution by the use of water coagulant in fibrous pulp form. Scanning electron micrographs show that the precipitated PBO pulps have a ribbon-like structure similar to Kevlar pulps. The thermalgravimetric analysis (TGA) show there were no appreciable mass changes until 550 °C in the air. The process yields PBO pulps with different specific surface areas (SSA) depending on the stirring speed, stirring time and the concentration of the PBO/MSA solution. High SSA PBO pulps can be produced by increasing the stirring speed, prolonging the stirring time and reducing the concentration of the PBO/MSA solution.

The Dynamics for Aqueous Sodium Adsorption and Characterization of Natural Pyrophyllite

2011 ◽  
Vol 117-119 ◽  
pp. 1129-1132
Author(s):  
Bo Liu ◽  
Hai Feng Chen ◽  
Pei Song Tang
Keyword(s):  
Qualitative Analysis ◽  
Internal Structure ◽  
Electron Micrographs ◽  
Scanning Electron Micrographs ◽  
Adsorption Dynamics ◽  
Natural Mineral ◽  
Aqueous Sodium ◽  
Materials Used ◽  
Scanning Electron

In this experiment, pyrophyllite as the main materials used the flame photometer to measure adsorption. Using the qualitative analysis of the samples of XRD with internal structure and found that pyrophyllite used in the experiment as a natural mineral, the presence with other minerals. Meanwhile, scanning electron micrographs (SEM) from the display showed that the effect of pyrophyllite adsorption for cations should be more significant. Therefore, this experiment focused on the time, Na+ concentration, on the pyrophyllite and different pyrophyllite concentrations (adsorbent dosage) effect on the adsorption, in addition to the adsorption dynamics. The results showed that pyrophyllite adsorption sodium in the best time of equilibrium was 20 minutes, the concentration of NaCl was 50 mg/L, pH = 7, temperature was 313 K, the concentration of pyrophyllite was 5 mg/L.

Nitrogen adsorption on synthetic akaganeite and its structural implications

Clay Minerals ◽  
1977 ◽  
Vol 12 (4) ◽  
pp. 345-352 ◽  
Author(s):  
E. Paterson ◽  
J. M. Tait
Keyword(s):  
Specific Surface ◽  
Electron Micrographs ◽  
Nitrogen Adsorption ◽  
Structural Scheme ◽  
Qualitative And Quantitative ◽  
Surface Areas ◽  
Two Samples ◽  
Specific Surface Areas ◽  
Adsorptive Properties ◽  
Quantitative Assessments

AbstractComparison of the adsorptive properties of two samples of akaganéite prepared by different methods shows that a structural scheme based upon solid rods is much more likely than a previously proposed scheme involving tubes. Specific surface areas, qualitative and quantitative assessments of porosity' and electron micrographs strongly support this structure.

Preparation and characterization of titanium oxynitrides with high specific surface areas

1991 ◽  
Vol 95 (1) ◽  
pp. 145-155 ◽  
Author(s):  
Chae Ho Shin ◽  
Guy Bugli ◽  
Gerald Djega-Mariadassou
Keyword(s):  
Specific Surface ◽  
Surface Areas ◽  
Specific Surface Areas

Synthesis and Characterization of Hydrotalcites: [Zn1−xAlx(OH)2](CO3)x/2·mH2O; x=0.25−0.66

1996 ◽  
Vol 454 ◽  
Author(s):  
M. A. Valenzuela ◽  
E. López-Salinas ◽  
B. Zapata ◽  
J. A. Montoya
Keyword(s):  
Thermal Treatment ◽  
Specific Surface ◽  
Calcination Temperature ◽  
Layered Structure ◽  
Synthesis And Characterization ◽  
Surface Areas ◽  
Constant Ph ◽  
Specific Surface Areas ◽  
Pure Phases

ABSTRACTIn this work a series of [Zn1−xAlx(OH)2](CO3)x/2·mH2O; x=0.25−0.66 were prepared at constant pH in order to study the effect of the thermal treatment on their crystalline srtucture. It was found that is possible to obtain pure Zn-Al hydrotalcite materials within a x = 0.25−0.50 range in comparison with Mg-Al hydrotalcites which yield pure phases in more restricted x ranges (0.25−0.33). All Zn-Al hydrotalcites lost their layered structure at temperatures above 473 K being less stable than their parental Mg-Al hydotalcite (623 K). Specific surface areas of these materials depended strongly on the Zn/Al ratio and calcination temperature, ranging from 280 to 20 m2/g. ZnO and ZnAl2O4 compounds were detected as the calcination products at temperatures higher than 873 K.

scholarly journals Effect of Imposed Shear Strain on Steel Ring Surfaces during Milling in High-Speed Disintegrator

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2234 ◽  
Author(s):  
Karel Dvořák ◽  
Adéla Macháčková ◽  
Simona Ravaszová ◽  
Dominik Gazdič
Keyword(s):  
Specific Surface ◽  
High Speed ◽  
Relative Increase ◽  
Coarse Particles ◽  
Cement Sample ◽  
Surface Areas ◽  
Original Mass ◽  
Specific Surface Areas ◽  
Ground Material

This contribution characterizes the performance of a DESI 11 high-speed disintegrator working on the principle of a pin mill with two opposite counter-rotating rotors. As the ground material, batches of Portland cement featuring 6–7 Mohs scale hardness and containing relatively hard and abrasive compounds with the specific surface areas ranging from 200 to 500 m2/kg, with the step of 50 m2/kg, were used. The character of the ground particles was assessed via scanning electron microscopy and measurement of the absolute/relative increase in their specific surface areas. Detailed characterization of the rotors was performed via recording the thermal imprints, evaluating their wear by 3D optical microscopy, and measuring rotor weight loss after the grinding of constant amounts of cement. The results showed that coarse particles are ground by impacting the front faces of the pins, while finer particles are primarily milled via mutual collisions. Therefore, the coarse particles cause higher abrasion and wear on the rotor pins; after the milling of 20 kg of the 200 m2/kg cement sample, the wear of the rotor reached up to 5% of its original mass and the pins were severely damaged.

scholarly journals Possibility of Using t-Plots, Obtained from Nitrogen Adsorption for the Valuation of Zeolites

1986 ◽  
Vol 3 (3) ◽  
pp. 159-166 ◽  
Author(s):  
P. Hudec ◽  
J. Novanský ◽  
S. Silhár ◽  
T. N. Trung ◽  
M. Zúbek ◽  
...  
Keyword(s):  
Specific Surface ◽  
Quantitative Estimation ◽  
Nitrogen Adsorption ◽  
Surface Areas ◽  
Bet Analysis ◽  
Zeolite Content ◽  
Synthetic Zeolites ◽  
Specific Surface Areas ◽  
Specific Volumes

Data of adsorption isotherms of nitrogen adsorption at 77 K on various samples of zeolites were measured. Besides derivation of specific surface area by BET analysis, samples were characterised by values obtained by t-plots; specific surface areas of mesopores and specific volumes of micropores are also calculated. Results show the value of the use of t-plot method for the characterization of microporosity changes in zeolites after various treatments, and also for quantitative estimation of zeolite content in natural zeolites and the crystallinity of synthetic zeolites.

scholarly journals Surface Characterization of Scheelites

1985 ◽  
Vol 2 (2) ◽  
pp. 121-130 ◽  
Author(s):  
J. E. Herrero García ◽  
J. M. Guil Pinto ◽  
A. Ruiz Paniego
Keyword(s):  
Surface Characterization ◽  
Mercury Porosimetry ◽  
Volume Distribution ◽  
Scheelite Structure ◽  
X Ray ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
Adsorption Desorption ◽  
Scanning Electron

Tungstates and molybdates of Ca, Sr and Cd have been prepared by precipitation. X-ray diffractograms prove them to be stoichiometric compounds with scheelite structure. The surface of the products and its evolution with thermal treatment have been studied by thermogravimetry and scanning electron microscopy. Finally, BET specific surface areas have been determined as well as pore volume distribution by adsorption-desorption of nitrogen and mercury porosimetry.

A new genus and four new species of millipedes from Tasmania, Australia (Diplopoda: Polydesmida: Dalodesmidae), with notes on male leg setae in some Tasmanian dalodesmids

Zootaxa ◽  
2004 ◽  
Vol 558 (1) ◽  
pp. 1 ◽  
Author(s):  
ROBERT MESIBOV
Keyword(s):  
New Species ◽  
Electron Micrographs ◽  
Type Species ◽  
New Genus ◽  
Scanning Electron Micrographs ◽  
Scanning Electron

Bromodesmus catrionae n. gen., n. sp. (type species), B. militaris n. sp., B. riparius n. sp. and B. rufus n. sp. are described. The new genus is characterized by greatly reduced paranota and a gonopod telopodite expanded at the distal end into a posteriorly concave hood fringed with teeth; the hood partly protects a long, curved, acutely pointed solenomerite. Male leg setation in the type species of six Tasmanian dalodesmid genera is briefly discussed and illustrated with scanning electron micrographs. The sphaerotrichome shaft is sharply pointed in Atrophotergum; gently tapered in Dasystigma, Lissodesmus and Tasmanodesmus; expanded at the tip in Bromodesmus; and entirely absent in Gasterogramma. Tips of the setae forming the dense ventral brush on male podomeres are gently tapered in Dasystigma and Lissodesmus, truncated in Gasterogramma, expanded in Bromodesmus and forked in Tasmanodesmus.

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