Poly(Styrene CO Acrylonitrile) Polyols. Modulus Enhancing Polyols for Urethane Polymers

1972 ◽  
Vol 45 (5) ◽  
pp. 1467-1484 ◽  
Author(s):  
F. E. Critchfield ◽  
J. V. Koleske ◽  
D. C. Priest
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Unique Feature ◽  
Dispersed Phase ◽  
Load Bearing ◽  
Precursor Particle ◽  
Vinyl Polymer ◽  
Poly Acrylonitrile ◽  
Excellent Stability

Abstract A novel class of polyols for polyurethane production was described in 19661. Their unique feature was the presence of an in situ polymerized vinyl polymer which markedly enchanes the modulus of the resultant polyurethane. The final product is a conventional polyol that contains a dispersion of the vinyl polymer. From among the numerous products investigated, a poly-(acrylonitrile) polyol was selected because of the excellent stability of the dispersion. Poly (acrylonitrile) polyols are opaque, cream-colored liquids with viscosities ranging from 1500 to 4500 cps, depending upon the nature of the polyol precursor. Particle size of the dispersed phase was reported to be between 0.25 and 0.5 micron as determined by electron microscopy. Poly (acrylonitrile) polyols have been used in slab-stock flexible foams as additives to conventional polyether polyols to improve load-bearing properties. More extensive utility has been identified in molding applications. Whitman described their use in producing integral skin urethane foams for uses such as automotive arm rests, horn buttons, mirror covers, etc.. Dunleavy discussed the use of polymer polyols in molded, microcellular urethane elastomers for automotive trim parts, particularly for "cosmetic" bumpers. More recently, Patten and Priest showed their utility in highly resilient automotive seating foam. In all of these applications the modulus enhancing characteristics of these polyols are particularly important.

Characterization of nanophase titania particles synthesized using in situ steric stabilization

1997 ◽  
Vol 12 (7) ◽  
pp. 1755-1765 ◽  
Author(s):  
A. G. Gaynor ◽  
R. J. Gonzalez ◽  
R. M. Davis ◽  
R. Zallen
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Phase Transformation ◽  
High Water ◽  
Molar Ratio ◽  
Transformation Behavior ◽  
X Ray ◽  
Infrared Techniques

Ultrafine titania particles were synthesized from titanium tetraethoxide (TEOT) dissolved in ethanol. The concentration of water and of the soluble polymer hydroxypropylcellulose (HPC) were varied to control particle size. The HPC adsorbed onto the titania particles during growth, providing a steric barrier to aggregation. Electron microscopy showed that particles smaller than 70 nm were formed at high water concentrations (R > 120 where R is the molar ratio [H2O]/[TEOT]) and in the presence of HPC. The annealing-induced, phase-transformation behavior of these particles (amorphous → anatase → rutile) from 100 to 1000 °C was characterized by x-ray, Raman, and infrared techniques. The conversion of anatase to rutile occurred more readily for particles made at high water concentrations and with HPC. For particles formed by premixing TEOT with HPC prior to hydrolysis at R = 155, an 800 °C anneal yielded a rutile fraction exceeding 95%; particles made at R = 5.5 with no HPC showed negligible conversion at this temperature.

Potential Advantages of Poly(Acrylonitrile-Co-Methyl Acrylate)/Sodium Silicate Nanocomposites over P(An-Co-Ma) Copolymer

2009 ◽  
Vol 17 (6) ◽  
pp. 385-394
Author(s):  
Bijayashree Samal ◽  
Pradeep Kumar Rana ◽  
Prafulla Kumar Sahoo
Keyword(s):  
Electron Microscopy ◽  
Sodium Silicate ◽  
Methyl Acrylate ◽  
Thermo Gravimetric Analysis ◽  
Ammonium Persulfate ◽  
Polymerization Process ◽  
Gravimetric Analysis ◽  
Soil Burial ◽  
Poly Acrylonitrile

Poly (acrylonitrile-co-methyl acrylate) copolymer and P(AN-co-MA)/sodium silicate (SS) nanocomposite were synthesized via non-conventional emulsion method using an in situ transition metal complex Co(II)/EDTA and ammonium persulfate (APS) as initiator. The copolymer and nanocomposite so obtained were characterized and the results were compared. UV-visible spectral analysis revealed various interactions between the in situ complex and other reaction components. Infrared and 1H NMR spectra confirmed the formation of the P(AN-co-MA) copolymer and P(AN-co-MA)/SS nanocomposite. Furthermore, as evidenced by transmission electron microscopy (TEM), the composite obtained was found to have nano scale structure. X-ray diffraction (XRD) studies were carried out to analyze the aqueous dispersions of silicate with monomers, initiators, and monomers with initiators. For P(AN-co-MA) copolymer and P(AN-co-MA)/SS nanocomposite, XRD results confirmed that the silicate layers were exfoliated in the copolymer matrix during the polymerization process. An increase in the thermal stability for the nanocomposite was recorded by thermo gravimetric analysis (TGA). In comparison with the P(AN-co-MA) copolymer, the new P(AN-co-MA)/SS nanocomposite was found to show super absorbency and was biodegradable when tested by soil burial, activated sludge and cultured media and further confirmed by scanning electron microscopy (SEM).

scholarly journals DEPENDENCE OF THE VISCOSITY COEFFICIENT OF THE NIOSOMAL DISPERSION ON THE TEMPERATURE AND PARTICLE SIZE OF THE DISPERSED PHASE

2021 ◽  
Vol 61 (2) ◽  
pp. 336-341
Author(s):  
Elena Igorevna Diskaeva ◽  
Olga Vladimirovna Vecher ◽  
Igor Alexandrovich Bazikov ◽  
Karine Sergeevna Elbekyan ◽  
Elena Nikolaevna Diskaeva
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Volume Concentration ◽  
Statistical Data ◽  
Viscosity Coefficient ◽  
Dispersed Phase ◽  
Average Size ◽  
Increasing Temperature ◽  
Scanning Electron

The aim of this study was to experimentally investigate the dependence of viscosity coefficient of niosomal dispersion based on PEG-12 Dimethicone on the temperature and size of niosomes vesicles. The experiments were carried out with niosomes, the average size of which varied from 85 to 125 nm. The temperature varied from 20 to 60 °C, the volume concentration varied from 1 to 10 %. The particle size was determined by scanning electron microscopy (SEM) with subsequent statistical data processing. This study showed that the viscosity of niosomal dispersions significantly depends on both the temperature and the size of niosomes vesicles. With increasing temperature, the viscosity of niosomal dispersions decreases and with increasing particle size, the viscosity increases.

Immunocytochemistry. A Review of Methodology for Electron Microscopic Applicaiton

1974 ◽  
Vol 32 ◽  
pp. 328-329
Author(s):  
Joseph E. Mazurkiewicz
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Ultrastructural Level ◽  
Electron Microscopic ◽  
Biological Interest ◽  
Investigative Approach ◽  
Immunologic Activity ◽  
Dense Label

Immunocytochemistry is a powerful investigative approach in which one of the most exacting examples of specificity, that of the reaction of an antibody with its antigen, isused to localize tissue and cell specific molecules in situ. Following the introduction of fluorescent labeled antibodies in T950, a large number of molecules of biological interest had been studied with light microscopy, especially antigens involved in the pathogenesis of some diseases. However, with advances in electron microscopy, newer methods were needed which could reveal these reactions at the ultrastructural level. An electron dense label that could be coupled to an antibody without the loss of immunologic activity was desired.

Electron Microscopy of Mycoplasma Pneumoniae

1971 ◽  
Vol 29 ◽  
pp. 258-259 ◽  
Author(s):  
E. S. Boatman ◽  
G. E. Kenny
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Growth Phase ◽  
Hela Cells ◽  
Sulfonic Acid ◽  
Gamma Globulin ◽  
Horse Serum ◽  
Morphological Aspects ◽  
The Family

Information concerning the morphology and replication of organism of the family Mycoplasmataceae remains, despite over 70 years of study, highly controversial. Due to their small size observations by light microscopy have not been rewarding. Furthermore, not only are these organisms extremely pleomorphic but their morphology also changes according to growth phase. This study deals with the morphological aspects of M. pneumoniae strain 3546 in relation to growth, interaction with HeLa cells and possible mechanisms of replication.The organisms were grown aerobically at 37°C in a soy peptone yeast dialysate medium supplemented with 12% gamma-globulin free horse serum. The medium was buffered at pH 7.3 with TES [N-tris (hyroxymethyl) methyl-2-aminoethane sulfonic acid] at 10mM concentration. The inoculum, an actively growing culture, was filtered through a 0.5 μm polycarbonate “nuclepore” filter to prevent transfer of all but the smallest aggregates. Growth was assessed at specific periods by colony counts and 800 ml samples of organisms were fixed in situ with 2.5% glutaraldehyde for 3 hrs. at 4°C. Washed cells for sectioning were post-fixed in 0.8% OSO4 in veronal-acetate buffer pH 6.1 for 1 hr. at 21°C. HeLa cells were infected with a filtered inoculum of M. pneumoniae and incubated for 9 days in Leighton tubes with coverslips. The cells were then removed and processed for electron microscopy.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

Application of analytical electron microscopy to the study of partitioning of silicon in a 2 wt% Si eutectoid steel

1978 ◽  
Vol 36 (1) ◽  
pp. 616-617
Author(s):  
N. Ridley ◽  
S.A. Al-Salman ◽  
G.W. Lorimer
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Analytical Electron Microscopy ◽  
Eutectoid Steel ◽  
Minimum Diameter ◽  
Thin Foils ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Transformation Front

The application of the technique of analytical electron microscopy to the study of partitioning of Mn (1) and Cr (2) during the austenite-pearlite transformation in eutectoid steels has been described in previous papers. In both of these investigations, ‘in-situ’ analyses of individual cementite and ferrite plates in thin foils showed that the alloying elements partitioned preferentially to cementite at the transformation front at higher reaction temperatures. At lower temperatures partitioning did not occur and it was possible to identify a ‘no-partition’ temperature for each of the steels examined.In the present work partitioning during the pearlite transformation has been studied in a eutectoid steel containing 1.95 wt% Si. Measurements of pearlite interlamellar spacings showed, however, that except at the highest reaction temperatures the spacing would be too small to make the in-situ analysis of individual cementite plates possible, without interference from adjacent ferrite lamellae. The minimum diameter of the analysis probe on the instrument used, an EMMA-4 analytical electron microscope, was approximately 100 nm.

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