Characteristics of Particle Sizes produced by suspension polymerization of styrene

1992 ◽  
Vol 9 (1-4) ◽  
pp. 151-153 ◽  
Author(s):  
Michael Stamatoudis ◽  
Christina Apostolidou
Keyword(s):  
Suspension Polymerization ◽  
Particle Sizes

Effects of triethoxy and triphenylvinylsilanes on the porous structure of cross-linked poly(methyl methacrylate) beads

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Javaherian Naghash Hamid ◽  
Dehghan Fariba ◽  
Massah Ahmad Reza
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Suspension Polymerization ◽  
Particle Sizes ◽  
Swelling Ratio ◽  
Measurement Results ◽  
Swelling Studies ◽  
Volume Swelling ◽  
First Time ◽  
Scanning Electron

AbstractNovel microprous beads with the particle size of about 0.6-1.1 mm were prepared for the first time, from methylmethacrylate (MMA), ethyleneglycol dimethacrylate (EGDM), triethoxyvinylsilane (TEVS) and triphenylvinylsilane (TPVS) by suspension polymerization technique. In this study toluene was used as solvent. The swelling measurement results indicate that increasing silicone concentration increases the amount of pores and porosity percent, the weight swelling ratio, and particle sizes, but it has been observed that the apparent density decreases in the case of TEVS, and not in the case of TPVS. Also it has been demonstrated that the volume swelling ratio is independent of TEVS and increases by increasing TPVS concentration. The resulting copolymer beads were characterized by using swelling studies and Fourier transform infrared spectroscopy (FTIR). The morphology of copolymer beads were also investigated by scanning electron microscopy (SEM) and optical microscopy (OM).

Preparation and Characterization of Thermally Expandable Microspheres

2016 ◽  
Vol 852 ◽  
pp. 596-600 ◽  
Author(s):  
Shu Ying Chen ◽  
Zhi Cheng Sun ◽  
Lu Hai Li
Keyword(s):  
Suspension Polymerization ◽  
Volume Ratio ◽  
Particle Sizes ◽  
Phase Volume ◽  
Structure And Property ◽  
Structure Characteristics ◽  
Phase Volume Ratio ◽  
Foaming Temperature ◽  
Crosslinking Agents

The thermally expandable microspheres were prepared through suspension polymerization with acrylonitrile (AN), methyl methacrylate (MMA) and methyl acrylate (MA) as monomers. The experimental results showed that it was possible to apply suspension polymerization to prepare the high foaming ratio and equally distributed microcapsules when water and oil phase volume ratio of 3:1, AN-MMA-MA in the proportion of 70%/20%/10% (m/m/m), and 1,4-butanediol dimethacrylate (BDDMA) as the crosslinking agents. Furthermore, the structure and property of shell and nuclear were characterized by Infrared Spectra (IR), Scanning Electron Microscopy (SEM) and Thermal analysis (TG, DTG). The structure characteristics and effective factors of copolymer coated core materials, morphologies, particle sizes, foaming temperature and ratio of microcapsules were investigated in this paper.

Characterization of carbides in M50NiL

1991 ◽  
Vol 49 ◽  
pp. 606-607
Author(s):  
L. S. Lin ◽  
K. P. Gumz ◽  
A. V. Karg ◽  
C. C. Law
Keyword(s):  
Temperature Effects ◽  
Base Composition ◽  
Lattice Parameter ◽  
Control Surface ◽  
Carbide Formation ◽  
Particle Sizes ◽  
Low Carbon ◽  
Fee Structure ◽  
Heat Treated

Carbon and temperature effects on carbide formation in the carburized zone of M50NiL are of great importance because they can be used to control surface properties of bearings. A series of homogeneous alloys (with M50NiL as base composition) containing various levels of carbon in the range of 0.15% to 1.5% (in wt.%) and heat treated at temperatures between 650°C to 1100°C were selected for characterizations. Eleven samples were chosen for carbide characterization and chemical analysis and their identifications are listed in Table 1.Five different carbides consisting of M6C, M2C, M7C3 and M23C6 were found in all eleven samples examined as shown in Table 1. M6C carbides (with least carbon) were found to be the major carbide in low carbon alloys (<0.3% C) and their amounts decreased as the carbon content increased. In sample C (0.3% C), most particles (95%) encountered were M6C carbide with a particle sizes range between 0.05 to 0.25 um. The M6C carbide are enriched in both Mo and Fe and have a fee structure with lattice parameter a=1.105 nm (Figure 1).

TEM study on fine carbide precipitates and dislocation cell structure

1990 ◽  
Vol 48 (4) ◽  
pp. 904-905
Author(s):  
Mengzhe Chen ◽  
Siqin Wang ◽  
Jun Ke
Keyword(s):  
Carbide Particle ◽  
Cell Structure ◽  
Ferrite Matrix ◽  
Dislocation Cell ◽  
Isothermal Treatment ◽  
Particle Sizes ◽  
Dislocation Cell Structure ◽  
Thin Foils ◽  
Hsla Steels ◽  
Fine Carbide

A series of investigations have been conducted into the nature and origin of the dislocation cell structure. R.J.Klassen calculated that the dislocation cell limiting size in pure ferrite matrix is about 0.4 μm. M.N.Bassion estimated the size of dislocation cell in deformed ferrite of HSLA steels to be of the same order.In this paper, TEM observation has been concentrated on the interaction of fine carbide precipitates with dislocation cell structure in deformed Fe-C-V (0.05%C, 0.13% and 0.57%V) and Fe-C-Nb (0.07 %C and 0.04%Nb) alloys and compared with that in Fe-C (0.05%). Specimens were austenitized at 1500 “C/20 min and followed by isothermal treatment at 750 °C and 800 “C for 20, 40 and 120 minutes . The carbide particle sizes in these steels are from 9 to 86nm measured from carbon extraction replicas. Specimens for TEM were cut from differently deformed areas of tensile specimens deformed at room temperture. The thin foils were jet electropolished at -20 C in a solution of 10% perchloric acid and 90% ethanol. The TEM observation was carried out in JEM 100CX , EM420 at 100kv and JEM 2000FX at 200kv.

A High Resolution Study of Alumina Supported Iridium Catalysts

1980 ◽  
Vol 38 ◽  
pp. 202-203
Author(s):  
C. Stoeckert ◽  
B. Etherton ◽  
M. Beer ◽  
J. Gryder
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Metal Particles ◽  
Optical Transfer Function ◽  
Particle Sizes ◽  
Iridium Catalysts ◽  
Transmission Electron ◽  
Optical Transfer ◽  
Conventional Transmission Electron Microscope ◽  
Resolution Study

The interpretation of the activity of catalysts requires information about the sizes of the metal particles, since this has implications for the number of surface atoms available for reaction. To determine the particle dimensions we used a high resolution STEM1. Such an instrument with its simple optical transfer function is far more suitable than a conventional transmission electron microscope for the establishment of particle sizes. We report here our study on the size and number distribution of Ir particles supported on Al2O3 and also examine simple geometric models for the shape of Ir particles.

Separation of Plasminogen Activators from Human Uterine Tissue and a Comparison with Activators from Human Urine and Porcine Tissue

1979 ◽  
Vol 41 (04) ◽  
pp. 718-733 ◽  
Author(s):  
Preben Kok
Keyword(s):  
Plasminogen Activator ◽  
Human Urine ◽  
Gel Filtration ◽  
Ammonium Thiocyanate ◽  
Plasminogen Activators ◽  
Particle Sizes ◽  
Uterine Tissue ◽  
Porcine Tissue ◽  
Major Activity ◽  
Proliferative Phase

SummaryThree types of plasminogen activator could be distinguished in extracts from human uterine tissue. The activators differed in thermostability or in mode of inhibition by EACA.All the extracts contained stable as well as labile activators. The saline extracts were uniformly inhibited by increasing concentrations of EACA. Extracts made with 2 M ammonium thiocyanate were either uniformly inhibited by EACA or showed deflections indicating contamination with an activator, which was inhibited in a biphasic manner. It was possible to distinguish between: (1) An activator, abundantly present in the tissue, which was uniformly inhibited and stable. (2) Another uniformly inhibited activator, which was labile. (3) An activator, inhibited in a biphasic manner, similar to urokinase, which was present in varying amounts in uteri with the endometrium in the proliferative phase.Gel filtration of the uterine extracts showed two major activity peaks corresponding to particle sizes of 60,000 dalton and about 10,000 dalton.Antiserum to purified plasminogen activator, prepared from porcine ovaries, inhibited the activity of the human uterine extracts, but not the activities of human urokinase or urine. Urokinase antiserum in a concentration completely inhibiting human urine or urokinase, inhibited only 10% or less of the activities of human uterine extracts.

Flexographic ink-coating interactions: effects of latex variations in coating layers

TAPPI Journal ◽  
2016 ◽  
Vol 15 (4) ◽  
pp. 253-262 ◽  
Author(s):  
ERIK BOHLIN ◽  
CAISA JOHANNSON ◽  
MAGNUS LESTELIUS
Keyword(s):  
Contact Angles ◽  
High Ratio ◽  
Print Quality ◽  
Particle Sizes ◽  
Mixed Composition ◽  
Coating Surface ◽  
Covered Area ◽  
Surface Optical ◽  
Flexographic Printing ◽  
Coating Formulation

The effect of coating structure variations on flexographic print quality was studied using pilot-coated paperboard samples with different latex content and latex particle sizes. Two latexes, with particle sizes of 120 nm and 160 nm, were added at either 12 parts per hundred (pph) or 18 pph to the coating formulation. The samples were printed with full tone areas at print forces of 25 N and 50 N in a laboratory flexographic printing press using a waterbased ink. A high ratio of uncovered areas (UCAs) could be detected for the samples that contained 18 pph latex printed at a print force of 25 N. UCAs decreased with increased print force and with decreased amounts of latex in the coating formulation. The fraction of latex covered area on the coating surface was estimated to be 0.35–0.40 for the 12 pph, and 0.70–0.75 for the 18 pph samples. The ink penetration depth into the coating layer could be linked to the fraction of latex-free areas on the coating surface. Optical cross section microscopy indicated that a higher printing force did not increase the depth of penetrated ink to any greater extent. Higher printing force did increase contact between plate and substrate, leading to an improved distribution of the ink. This, in turn, increased print density and decreased UCAs. On closer inspection, the UCAs could be categorized as being induced by steep topographic changes. When appearing at other locations, they were more likely to be caused by poor wetting of the surface. To understand the wetting behavior of the coating surface, observed contact angles were compared with calculated contact angles on surfaces of mixed composition.

Surface energy of cellulosic materials: The effect of particle morphology, particle size, and hydroxyl number

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 565-576 ◽  
Author(s):  
YUCHENG PENG ◽  
DOUGLAS J. GARDNER
Keyword(s):  
Particle Size ◽  
Surface Energy ◽  
Particle Morphology ◽  
Nanofibrillated Cellulose ◽  
Particle Sizes ◽  
Hydroxyl Number ◽  
Small Individual ◽  
Dispersion Component ◽  
Commercial Applications ◽  
Lower Temperature

Understanding the surface properties of cellulose materials is important for proper commercial applications. The effect of particle size, particle morphology, and hydroxyl number on the surface energy of three microcrystalline cellulose (MCC) preparations and one nanofibrillated cellulose (NFC) preparation were investigated using inverse gas chromatography at column temperatures ranging from 30ºC to 60ºC. The mean particle sizes for the three MCC samples and the NFC sample were 120.1, 62.3, 13.9, and 9.3 μm. The corresponding dispersion components of surface energy at 30°C were 55.7 ± 0.1, 59.7 ± 1.3, 71.7 ± 1.0, and 57.4 ± 0.3 mJ/m2. MCC samples are agglomerates of small individual cellulose particles. The different particle sizes and morphologies of the three MCC samples resulted in various hydroxyl numbers, which in turn affected their dispersion component of surface energy. Cellulose samples exhibiting a higher hydroxyl number have a higher dispersion component of surface energy. The dispersion component of surface energy of all the cellulose samples decreased linearly with increasing temperature. MCC samples with larger agglomerates had a lower temperature coefficient of dispersion component of surface energy.

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