Application of Infrared Absorption Spectra to Studies of the Oxidation of Sodium-Butadiene Rubber

1951 ◽  
Vol 24 (3) ◽  
pp. 591-596
Author(s):  
B. Dogadkin ◽  
B. Kasatochkin ◽  
N. Klauzen ◽  
A. Smirnova
Keyword(s):  
Quantitative Analysis ◽  
Molecular Oxygen ◽  
Structural Changes ◽  
Chemical Properties ◽  
Butadiene Rubber ◽  
Physical And Chemical Properties ◽  
Reaction Products ◽  
Infrared Absorption Spectra ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract The reaction of rubber with molecular oxygen explains well the structural changes which take place in rubber during aging and during a number of important technological processes, such as plasticization and vulcanization. Furthermore, during vulcanization, in addition to its reaction with the vulcanizing agent, rubber also reacts with oxygen contained in the mixture. This may be one of the reasons for an optimum point of vulcanization. However, it is difficult to explain the changes of physical properties of rubber by simple union of oxygen, with formation of oxygen-bearing groups. To account for the changes observed, addition of a large quantity of oxygen would be necessary, whereas actually notable changes are brought about by the absorption of only 2–3 per cent of oxygen. To explain this, it must be assumed that oxygen causes structural changes in rubber and that these changes become evident when the percentage of oxygen in the reaction products is still negligible. In the case of sodium-butadiene rubber, as was shown by one of the authors, this reaction at any particular temperature causes an increase of strength and of elasticity, and a loss of solubility. The object of the present investigation was a qualitative and limited quantitative analysis of those groups which originate during oxidation and also an examination of the structures which determine the changes of the physical and chemical properties in the reaction of rubber with molecular oxygen.

Experimental Investigation on Grinding Temperature of Titanium Alloy

2014 ◽  
Vol 1027 ◽  
pp. 127-130 ◽  
Author(s):  
Bing Jun Hao ◽  
Zhi Gang Dong ◽  
Ren Ke Kang ◽  
Huan Wang ◽  
Ke Cao
Keyword(s):  
Titanium Alloy ◽  
Structural Changes ◽  
Thermal Damage ◽  
Elevated Temperatures ◽  
Chemical Properties ◽  
Grinding Temperature ◽  
Physical And Chemical Properties ◽  
Machine Material ◽  
Physical And Chemical ◽  
And Chemical Properties

Titanium alloy has been widely used in aeronautics and astronautics industry owing to its unique combinations of properties. The unique physical and chemical properties of titanium alloy make it a typical difficult-to-machine material. The elevated temperatures at the machining zones may cause thermal damage, residual stress and micro-structural changes in the surface layer of titanium alloy during grinding. In this study, grinding experiments were performed on the titanium alloy, and the grinding temperature was experimentally tested with the grindable thermocouples. The effects of the grinding parameters on the grinding temperature were analyzed. The grinding temperature rises with the increase of grinding speed and grinding depth.

Effects of interaction between montmorillonite and Sphingomonas sp. GY2B on the physical and chemical properties of montmorillonite in the clay-modulated biodegradation of phenanthrene

2018 ◽  
Vol 15 (5) ◽  
pp. 296 ◽  
Author(s):  
Bo Ruan ◽  
Pingxiao Wu ◽  
Huimin Wang ◽  
Liping Li ◽  
Langfeng Yu ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Structural Changes ◽  
Morphological Changes ◽  
Chemical Properties ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Valuable Insight ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

Environmental contextInteractions between microbes and minerals can influence geochemical reactions, and hence are of fundamental importance in natural environmental processes. We investigate the effects of Sphingomonas sp. on the structure and physicochemical properties of montmorillonite, a common clay mineral, and determine how this interaction influences the biodegradation of phenanthrene. The findings have profound impact on the clay-modulated biodegradation of organic compounds in the environment. AbstractWe investigate the effect of Sphingomonas sp. GY2B on the structure and physicochemical properties of montmorillonite (Mt). The simultaneous biodegradation of a polycyclic aromatic hydrocarbon compound, phenanthrene, was also monitored. After interaction with bacteria for 2 days, the increases of the specific surface area (SSA) and micropore volume, differences of the thermogravimetric analysis and differential scanning calorimetry (TGA-DSC) patterns and the morphological changes revealed modification of the physicochemical properties and mineral surface. Although the interlayer spacing of Mt remained unchanged, the appearance and shift of several vibration peaks in the Fourier transform infrared (FTIR) spectra confirmed the structural changes of Mt arising from bacterial activities. Concentrations of the major elements of montmorillonite changed greatly in the aqueous solution, especially Si, Al, Fe and Ca. Based on the analyses of X-ray diffraction (XRD) and FTIR, these changes were mainly ascribed to the formation of precipitates and minerals in the biotic experiment. Changes in the release rate of different elements also substantiated that the GY2B strain has a considerable impact on the dissolution of montmorillonite. Additionally, a preferential release of Si and the 27Al and 29Si cross-polarisation magic-angle spinning nuclear magnetic resonance (CP/MAS NMR) spectra of bacteria-untreated samples demonstrated that tetrahedral sheets were preferentially destroyed and octahedral sheets in montmorillonite were dissolved. These results showed that microorganisms can greatly affect the physical and chemical properties of clay minerals in the clay-modulated biodegradation of hydrophobic organic contaminants. This study provides valuable insight into the clay-modulated microbial remediation of organic pollutants in the environment.

Analysis of the Major Alternaria Toxins

1984 ◽  
Vol 47 (12) ◽  
pp. 978-995 ◽  
Author(s):  
JOHN E. SCHADE ◽  
A. DOUGLAS KING
Keyword(s):  
Quantitative Analysis ◽  
Secondary Metabolites ◽  
Chemical Properties ◽  
Monomethyl Ether ◽  
Physical And Chemical Properties ◽  
Tenuazonic Acid ◽  
Alternariol Monomethyl Ether ◽  
Analytical Methodology ◽  
Physical And Chemical ◽  
And Chemical Properties

Some physical and chemical properties of 40 secondary metabolites produced by Alternaria are tabulated along with literature references. Analytical methodology for three of the several classes of these potential toxins is reviewed in depth, because compounds in these classes are produced in relatively large amounts by many Alternaria and/or are apparently very toxic or mutagenic. Tenuazonic acid, alternariol and alternariol monomethyl ether represent the major toxins in terms of both quantity produced and toxicity. The altertoxins, although produced in very small amounts, are included because of their apparent toxicity/mutagencity. Published methods used to isolate and purify or analyze these important toxins are grouped for comparison according to similarities in extraction, isolation and analysis. Methods used for quantitative analysis are separated from those used primarily for preparation and purification. Published detection limits and recoveries are compared. Analytical needs and prospects are discussed.

scholarly journals The optical, physical and chemical properties of the products of glyoxal uptake on ammonium sulfate seed aerosols

2011 ◽  
Vol 11 (7) ◽  
pp. 19223-19252 ◽  
Author(s):  
M. Trainic ◽  
A. A. Riziq ◽  
A. Lavi ◽  
J. M. Flores ◽  
Y. Rudich
Keyword(s):  
Gas Phase ◽  
Cross Section ◽  
Imaginary Part ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Reaction Products ◽  
Extinction Cross Section ◽  
Optical Extinction ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract. The heterogeneous reaction between gas phase glyoxal and ammonium sulfate (AS) aerosols, a proxy for inorganic atmospheric aerosol, was studied in terms of the dependence of the optical, physical and chemical properties of the product aerosols on initial particle size and ambient RH. The reactions were studied under different relative humidity (RH) conditions, varying from dry conditions (~20 % RH) and up to 90 % RH, covering conditions prevalent in many atmospheric environments. At λ = 355 nm, the reacted aerosols demonstrate a substantial growth in optical extinction cross section, as well as in mobility diameter under a broad range of RH values (35–90 %). The ratio of the product aerosol to seed aerosol geometric cross section reached up to ~3.5, and the optical extinction cross-section up to ~250. The reactions show a trend of increasing physical and optical growth with decreasing seed aerosol size, from 100nm to 300 nm, as well as with decreasing RH values from 90 % to ~40 %. Optically inactive aerosols, at the limit of the Mie range (100 nm diameter) become optically active as they grow due to the reaction. AMS analyses of the reaction of 300 nm AS at RH values of 50 %, 75 % and 90 % show that the main products of the reaction are glyoxal oligomers, formed by acetal formation in the presence of AS. In addition, imidazole formation, which is a minor channel, is observed for all reactions, yielding a product which absorbs at λ = 290 nm, with possible implications on the radiative properties of the product aerosols. The ratio of absorbing substances (C–N compounds, including imidazoles) increases with increasing RH value. A core/shell model used for the investigation of the optical properties of the reaction products of AS 300nm with gas phase glyoxal, shows that the refractive index (RI) of the reaction products are in the range between 1.57–1.71 for the real part and between 0–0.02 for the imaginary part of the RI at 355 nm. The observed increase in the ratio of the investigated absorbing substances is slightly indicated in the RI values found by the model, as the imaginary part of the product RI increases from 0.01 to 0.02 with increasing RH. The imaginary part is expected to increase further at higher RH and become more substantial in cloud droplets. This study shows that the reaction of abundant substances present in atmospheric aerosols, such as AS, and gas phase glyoxal alters the aerosols' optical, physical and chemical properties and may have implications on the radiative effect of these aerosols.

scholarly journals The optical, physical and chemical properties of the products of glyoxal uptake on ammonium sulfate seed aerosols

2011 ◽  
Vol 11 (18) ◽  
pp. 9697-9707 ◽  
Author(s):  
M. Trainic ◽  
A. Abo Riziq ◽  
A. Lavi ◽  
J. M. Flores ◽  
Y. Rudich
Keyword(s):  
Gas Phase ◽  
Cross Section ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Reaction Products ◽  
Extinction Cross Section ◽  
Optical Extinction ◽  
Physical And Chemical ◽  
Seed Aerosol ◽  
And Chemical Properties

Abstract. The heterogeneous reaction between gas phase glyoxal and ammonium sulfate (AS) aerosols, a proxy for inorganic atmospheric aerosol, was studied in terms of the dependence of the optical, physical and chemical properties of the product aerosols on initial particle size and ambient relative humidity (RH). Our experiments imitate an atmospheric scenario of a dry particle hydration at ambient RH conditions in the presence of glyoxal gas followed by efflorescence due to decrease of the ambient RH. The reactions were studied under different RH conditions, starting from dry conditions (~20% RH) and up to 90% RH, covering conditions prevalent in many atmospheric environments, and followed by consequent drying of the reacted particles before their analysis by the aerosol mass spectrometer (AMS), cavity ring down (CRD) and scanning mobility particle sizer (SMPS) systems. At λ = 355 nm, the reacted aerosols demonstrate a substantial growth in optical extinction cross section, as well as in mobility diameter under a broad range of RH values (35–90%). The ratio of the product aerosol to seed aerosol geometric cross section reached up to ~3.5, and the optical extinction cross-section up to ~250. The reactions show a trend of increasing physical and optical growth with decreasing seed aerosol size, from 100 nm to 300 nm, as well as with decreasing RH values from 90% to ~40%. Optically inactive aerosols, at the limit of the Mie range (100 nm diameter) become optically active as they grow due to the reaction. AMS analyses of the reaction of 300 nm AS at RH values of 50%, 75% and 90% show that the main products of the reaction are glyoxal oligomers, formed by acetal formation in the presence of AS. In addition, imidazole formation, which is a minor channel, is observed for all reactions, yielding a product which absorbs at λ = 290 nm, with possible implications on the radiative properties of the product aerosols. The ratio of absorbing substances (C-N compounds, including imidazoles) increases with increasing RH value. A core/shell model used for the investigation of the optical properties of the reaction products of AS with gas phase glyoxal, shows that the refractive index (RI) of the reaction products are n= 1.68(±0.10)+0.01(±0.02) at 50% RH and n = 1.65(±0.06)+0.02(±0.01) at 75% RH at 355 nm. The observed increase in the ratio of the absorbing substances is not indicated in the imaginary part of the products at RH 50% and 75%. A further increase in the ratio of absorbing substances and a resulting increase in the imaginary part of the RI at higher RH values is expected, and may become even more substantial after longer reaction times, possibly in cloud or fog droplets. This study shows that the reaction of abundant substances present in atmospheric aerosols, such as AS, and gas phase glyoxal alters the aerosols' optical, physical and chemical properties and may have implications on the radiative effect of these aerosols.

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