Physical properties of organic acids

Abstract The reactions of rubber with aldehydes have previously been studied in latex or in solutions and the reaction products formed by cyclization, condensation, or addition, have been reported. In the present study, solid-state reactions of rubber with aldehydes were carried out. It was found that crosslinked rubbers may be obtained by press curing in the presence of aldehydes with acidic catalysts. Poly-chloroprene and Hypalon especially undergo these reactions without a catalyst or with a small amount of catalyst. In the experiments using various aldehydes, some improvements in the properties of the crosslinked rubber were observed when aldehydes such as paraformaldehyde or α-polyoxymethylene were used. Some Lewis acids such as SnCl2·2H2O were found to be more effective catalysts than the above, and it was found that organic acids such as p-toluenesulfonic acid could also be used. The curing seemed to be an ionic reaction. The physical properties of the crosslinked rubber are similar to those of sulfur-cured rubbers.

Download Full-text

City sewer collectors biocorrosion

Open Engineering ◽

10.2478/s13531-013-0177-7 ◽

2014 ◽

Vol 4 (4) ◽

Cited By ~ 4

Author(s):

Mariusz Ksia̧żek

Keyword(s):

Organic Acids ◽

Physical Properties ◽

Industrial Waste ◽

Soil Bacteria ◽

Waste Material ◽

Nitrifying Bacteria ◽

Organic Substrates ◽

The City

AbstractThis paper presents the biocorrosion of city sewer collectors impregnated with special polymer sulphur binders, polymerized sulphur, which is applied as the industrial waste material. The city sewer collectors are settled with a colony of soil bacteria which have corrosive effects on its structure. Chemoautotrophic nitrifying bacteria utilize the residues of halites (carbamide) which migrate in the city sewer collectors, due to the damaged dampproofing of the roadway and produce nitrogen salts. Chemoorganotrophic bacteria utilize the traces of organic substrates and produce a number of organic acids (formic, acetic, propionic, citric, oxalic and other). The activity of microorganisms so enables the origination of primary and secondary salts which affect physical properties of concretes in city sewer collectors unfavourably.

Download Full-text

Factors Affecting Rate of Vulcanization of Chloroprene Plastic Polymers

Rubber Chemistry and Technology ◽

10.5254/1.3547558 ◽

1933 ◽

Vol 6 (2) ◽

pp. 309-316

Author(s):

E. R. Bridgwater ◽

E. H. Krismann

Keyword(s):

Zinc Oxide ◽

Organic Acids ◽

Physical Properties ◽

Great Increase ◽

Substantial Improvement ◽

Factors Affecting ◽

Desirable Effect

Abstract These tests have clearly shown the desirability of compounding this polymer with zinc oxide, magnesia, and rosin, and have demonstrated that these three ingredients when used together have a desirable effect that cannot be obtained with, or even predicted from, the results obtained with any one of them alone or the combination of any two of them. It has been shown further that, although it is possible to obtain good vulcanized products from this polymer without the addition of sulfur, a great increase in the rate of cure and substantial improvement in physical properties of vulcanized products result from the use of as little as 0.5 per cent of sulfur on the weight of the polymer. it is further shown that pine tar and rosin oil may be substituted for rosin but that they are somewhat less efficacious. The authors postulate that the value of rosin, pine tar, and rosin oil is probably due to the organic acids that they contain. Coumarone resin and brown factice are shown to be desirable compounding ingredients for chloroprene polymers.

Download Full-text

Analysis of the influence and optimization of concentration of organic acids on chemical and physical properties of wheat dough using a response surface methodology and desirability function

Hemijska industrija ◽

10.2298/hemind120302039s ◽

2013 ◽

Vol 67 (1) ◽

pp. 103-113 ◽

Cited By ~ 1

Author(s):

Olivera Simurina ◽

Bojana Filipcev ◽

Pavle Jovanov ◽

Bojana Ikonic ◽

Dragana Simovic-Soronja

Keyword(s):

Experimental Data ◽

Ascorbic Acid ◽

Response Surface Methodology ◽

Citric Acid ◽

Organic Acids ◽

Physical Properties ◽

Regression Coefficient ◽

Desirability Function ◽

Dough Extensibility ◽

Main Effects

In order to improve physical and chemical properties of dough produced from wheat flour of suboptimal quality (protein content 10.7% dry basis, dough energy 4.0 cm2), optimal doses of ascorbic and citric acid were evaluated using a response surface methodology and desirability function. The paper brings the analysis of the main effects as well as their interactions. The effect of organic acids was evident in relation to pH lowering and decrease in free thiol groups, which consequently changed the physical properties of dough (increased dough energy, extensibility and resistance). The well known oxidative effect of ascorbic acid which is manifested as increase in dough energy and resistance, was enhanced by the addition of citric acid i.e. their synergistic action. Contribution of citric acid was the donation of hydrogen ions which changed the pH, lowered the content of free -SH groups and increased protein aggregation. Ascorbic acid individually significantly increased energy (linear regression coefficient b1 = 4.010-4) but higher effect was exerted by the addition of ascorbic and citric acid mixture as seen through higher interaction regression coefficient (b12 = 0.076). Dough resistance was significantly affected only by ascorbic acid due to its oxidizing action whereas dough extensibility was affected by both acids (main effects) at all applied doses and their mixtures. The effect on dough extensibility depends on the dose of acids but resistance decreased with quadratic increase of acid doses. Second-order polynomials were used in modeling of responses (dough energy, resistance and extensibility) which showed a good fit with experimental data as shown by high values of the coefficients of determination R2 for energy, resistance and extensibility (0.953, 0.976 and 0.996, respectively). Based on F value, it could be concluded that the model gave good prediction of experimental data while p-values for all responses showed that the models were significant at significance of 90%. The obtained models were used to optimize the doses of ascorbic and citric acid in order to maximize dough energy and extensibility. Significant increase of dough energy by 4.7 times and extensibility by 1.5 times was achieved by the set of optimum conditions of 97 mg/kg citric and 100 mg/kg ascorbic acid. The obtained results are applicable in semi-industrial and industrial facilities for flour processing.

Download Full-text

AVESTAPOLARIT 430

Alloy Digest ◽

10.31399/asm.ad.ss0828 ◽

2001 ◽

Vol 50 (8) ◽

Keyword(s):

Stainless Steel ◽

Corrosion Resistance ◽

Organic Acids ◽

Physical Properties ◽

Tensile Properties ◽

Ferritic Stainless Steel ◽

Alkaline Solutions ◽

Good Corrosion Resistance

Abstract AvestaPolarit 430 is a ferritic stainless steel with good corrosion resistance to the atmosphere, organic acids, detergents, and alkaline solutions. The alloy is easily formed and is used in decorative and trim work. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and joining. Filing Code: SS-828. Producer or source: AvestaPolarit AB.

Download Full-text

The Photometric Properties of the Ap Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100080684 ◽

1976 ◽

Vol 32 ◽

pp. 365-377 ◽

Cited By ~ 2

Author(s):

B. Hauck

Keyword(s):

Physical Properties ◽

Ap Stars

The Ap stars are numerous - the photometric systems tool It would be very tedious to review in detail all that which is in the literature concerning the photometry of the Ap stars. In my opinion it is necessary to examine the problem of the photometric properties of the Ap stars by considering first of all the possibility of deriving some physical properties for the Ap stars, or of detecting new ones. My talk today is prepared in this spirit. The classification by means of photoelectric photometric systems is at the present time very well established for many systems, such as UBV, uvbyβ, Vilnius, Geneva and DDO systems. Details and methods of classification can be found in Golay (1974) or in the proceedings of the Albany Colloquium edited by Philip and Hayes (1975).

Download Full-text

The Infection of Cells by Bullet-Shaped Viruses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063779 ◽

1969 ◽

Vol 27 ◽

pp. 372-373

Author(s):

Frederick A. Murphy ◽

Alyne K. Harrison ◽

Sylvia G. Whitfield

Keyword(s):

Electron Microscopy ◽

Physical Properties ◽

Host Cell ◽

Thin Section ◽

Cultured Cells ◽

Cell Infection ◽

Thin Section Electron Microscopy ◽

Section Electron ◽

Section Electron Microscopy

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.

Download Full-text

Transmission electron microscopy of composite materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107125 ◽

1988 ◽

Vol 46 ◽

pp. 1012-1015

Author(s):

K.P.D. Lagerlof

Keyword(s):

Composite Materials ◽

Physical Properties ◽

Structural Defects ◽

Structural Composites ◽

Multiphase Materials ◽

Structural Reinforcement ◽

Transmission Electron ◽

Reinforced Fiber ◽

Particulate Reinforced Composites ◽

Definition Of

Although most materials contain more than one phase, and thus are multiphase materials, the definition of composite materials is commonly used to describe those materials containing more than one phase deliberately added to obtain certain desired physical properties. Composite materials are often classified according to their application, i.e. structural composites and electronic composites, but may also be classified according to the type of compounds making up the composite, i.e. metal/ceramic, ceramic/ceramie and metal/semiconductor composites. For structural composites it is also common to refer to the type of structural reinforcement; whisker-reinforced, fiber-reinforced, or particulate reinforced composites [1-4].For all types of composite materials, it is of fundamental importance to understand the relationship between the microstructure and the observed physical properties, and it is therefore vital to properly characterize the microstructure. The interfaces separating the different phases comprising the composite are of particular interest to understand. In structural composites the interface is often the weakest part, where fracture will nucleate, and in electronic composites structural defects at or near the interface will affect the critical electronic properties.

Download Full-text