The Physico-Chemical Properties of Latex and Their Significance in Manufacture

1935 ◽  
Vol 8 (4) ◽  
pp. 501-513 ◽  
Author(s):  
E. W. Madge
Keyword(s):  
Adsorption Layer ◽  
Chemical Properties ◽  
Point Of View ◽  
Manufacturing Processes ◽  
Physico Chemical ◽  
Strong Adsorption ◽  
Hydrophilic Character ◽  
Dissolved And Suspended Matter ◽  
Actual Particle ◽  
Physico Chemical Property

Abstract The first physico-chemical property of latex to be discussed is that of viscosity, if latex can be said to have a viscosity. As will be seen later, this property is so important in many manufacturing processes, such as extrusion, dipping, and centrifuging that the fundamentals must be understood. Latex, as is well known, is a suspension of irregularly shaped particles, many pear-shaped, in an aqueous medium which itself contains an appreciable proportion of other dissolved and suspended matter. These particles, according to present ideas, are surrounded by a strong adsorption layer, which influences very considerably the properties of the latex. As a result of its composite structure, latex and more particularly latex compounds have rather interesting properties. From the point of view that latex creams under gravity, that the particle carries an appreciable electric charge, and depends partly on this for its stability, and that the swelling of the actual particle in water is very small, it may be called hydrophobic. On the other hand, in view of its behavior with respect to dehydrating agents, the manner in which it forms aqueous voluminous gels, and more particularly in its reaction to shearing forces, latex may be classed as hydrophilic. Its hydrophilic character is conditioned by the material adsorbed on the surface of the particles and is more pronounced in compounded and treated latices.

scholarly journals Separation of Biological Entities from Human Blood by Using Magnetic Nanocomposites Obtained from Zeolite Precursors

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1803
Author(s):  
Serena Esposito ◽  
Antonello Marocco ◽  
Gianfranco Dell’Agli ◽  
Barbara Bonelli ◽  
Franca Mannu ◽  
...  
Keyword(s):  
Human Blood ◽  
Chemical Properties ◽  
Industrial Process ◽  
High Sensitivity ◽  
Point Of View ◽  
The Novel ◽  
Magnetic Adsorbents ◽  
Physico Chemical ◽  
Magnetic Metal ◽  
Biological Entities

In this work, three novel magnetic metal–ceramic nanocomposites were obtained by thermally treating Fe-exchanged zeolites (either A or X) under reducing atmosphere at relatively mild temperatures (750–800 °C). The so-obtained materials were thoroughly characterized from the point of view of their physico-chemical properties and, then, used as magnetic adsorbents in the separation of the target gene factors V and RNASE and of the Staphylococcus aureus bacteria DNA from human blood. Such results were compared with those obtained by using a top ranking commercial separation system (namely, SiMAG-N-DNA by Chemicell). The results obtained by using the novel magnetic adsorbents were similar to (or even better than) those obtained by using the commercial system, both during manual and automated separations, provided that a proper protocol was adopted. Particularly, the novel magnetic adsorbents showed high sensitivity during tests performed with small volumes of blood. Finally, the feasible production of such magnetic adsorbents by an industrial process was envisaged as well.

SYNTHESIS OF SPATIALLY-HINDERED METHYLCYCLOALKYLPHENOLS AND SOME PECULIARITIES OF THEIR AMINOMETHYLATION REACTIONS BY AMINOETHYLNONYLIMIDAZOLINE

1970 ◽  
Author(s):  
Zaur Z. Aghamaliyev ◽  
Vagif M. Abbasov ◽  
Chingiz K. Rasulov ◽  
Igrar G. Nazarov ◽  
Nigar S. Rzaeva ◽  
...  
Keyword(s):  
Maximum Yield ◽  
Chemical Properties ◽  
Mannich Bases ◽  
Point Of View ◽  
Molar Ratio ◽  
Theoretical Point ◽  
Target Product ◽  
Substituted Phenols ◽  
Catalyst Amount ◽  
Physico Chemical

The paper deals with the results of cycloalkylation of phenol with 1-methylcyclopentene, 1(3)-methylcyclohexene in the presence of aluminum phenolate catalyst and influence of various parameters on the yield of the target product. The reaction temperature was varied from 220 to 280 °C, the reaction time - from 1 to 7 h, molar ratio of phenol to cyclene – from 1:1 to 1:3 mol/mol, the catalyst amount – from 10 to 25%. Maximum yield of 2,6-di(1(3)-methylcycloalkyl)phenols is obtained under the following conditions: temperature - 260-280 °C, duration - 5-6 h, molar ratio of phenol to 1(3)-methylcycloalkene - 1:2 mol/mol and the catalyst amount is 20% based on taken phenol. Simultaneously, the yield of the target products - 2,6-di-(1(3)-methylcycloalkyl)phenols is 44.3-47.1% per taken phenol, the selectivity is 67.4 71.2% on the target product. As a result of the chromatographic studies of the products of phenol cycloalkylation with 1(3)-methylcycloalkenes in the presence of aluminum phenolate catalyst it became clear that the alkylate mainly contains 2,6-dicycloalkyl-substituted phenols (87.4-92.3%). After rectification of the alkylate at low pressure (20 mm Hg), the target products were obtained with a purity of 96.7-98.1% and their physico-chemical properties were determined. The resulting 2,6-di-(1(3)-methylcycloalkyl)phenols were aminomethylated by formaldehyde and aminoethylnonylimidazoline at the ratio of 1:2:2.From theoretical point of view, Mannich bases were obtained with yield of 65.7-71.7% by the interaction of 2,6-di-[1(3)-methylcycloalkyl]phenols with formaldehyde and aminoethylnonyl imidazoline. Physico-chemical properties of synthesized 4-hydroxy-3,5-di-(1(3)-methylcycloalkyl)benzylaminoethylnonylimidazolines were determined.

Reaction of Elemental Sulfur and Mercaptobenzothiazole

1956 ◽  
Vol 29 (4) ◽  
pp. 1369-1372
Author(s):  
G. A. Blokh ◽  
E. A. Golubkova ◽  
G. P. Miklukhin
Keyword(s):  
Elemental Sulfur ◽  
Active Form ◽  
Chemical Properties ◽  
Intermediate Compound ◽  
Point Of View ◽  
Experimental Fact ◽  
Acceleration Process ◽  
Physico Chemical ◽  
Lower Temperature ◽  
Vulcanization Process

Abstract One of the most important problems in the field of the physics and chemistry of rubber is that of vulcanization. Until now no single theory has been established, which elucidates the complex physico-chemical changes which occur during this process. Still more obscure has been the mechanism of the action of vulcanization accelerators, which, as is well known, not only reduce the time and the temperature of vulcanization, but also influence the physico-mechanical and chemical properties of the rubber. Most investigators have assumed that in the acceleration process a reaction with sulfur converts it to an active form which is capable of bringing about vulcanization at a lower temperature and at a greater rate, than with ordinary elemental sulfur in the absence of an accelerator. This point of view is based on the experimental fact that the vulcanization of rubber by sulfur dioxide and hydrogen sulfide, for example, which form sulfur in the nascent condition, proceeds rapidly even at room temperature. Investigators have also assumed that in the vulcanization process activation of sulfur in the presence of accelerators may occur by different mechanisms. It is possible that the accelerator, reacting with elemental sulfur, forms unstable intermediate compounds, which decompose with liberation of sulfur in an active form. The latter reacts with rubber, and the regenerated accelerator reacts again with elemental sulfur, etc. However, a different process is possible for the activation of elemental sulfur. By this second mechanism the unstable combination of accelerator and sulfur reacts directly with rubber without the formation of active sulfur. Both these mechanisms necessarily assume the formation of intermediate unstable combinations of the accelerator with sulfur. However, direct, experimentally-based demonstrations of such an interaction are lacking in the literature. There exist only theoretical hypotheses concerning the nature of the possible intermediate combination of the accelerator with sulfur. According to Ostromislensky's concepts, further developed by Bedford, such an intermediate compound has the character of a polysulfide. According to Bruni and Romani, this intermediate compound is a disulfide. As is well known, the disulfide theory was placed in doubt by Zaide and Petrov on the basis of data from the vulcanization of rubber in the presence of benzothiazolyl disulfide.

USING SULFUR-CONTAINING MINERALS IN MEDICINE: IRANIAN TRADITIONAL DOCUMENTS AND MODERN PHARMACEUTICAL TERMINOLOGY

2018 ◽  
Vol 37 (1) ◽  
pp. 25-33 ◽  
Author(s):  
MAHBOOBEH PARVARESH DARBANDI ◽  
JAFAR TAHERI
Keyword(s):  
Chemical Properties ◽  
Sulfide Minerals ◽  
Point Of View ◽  
Ibn Sina ◽  
Sulfate Minerals ◽  
Advantages And Disadvantages ◽  
Bacterial Agent ◽  
Physico Chemical ◽  
New Findings ◽  
Selection Of

ABSTRACT Sulfur occurs naturally in the earth's crust as a pure element (native sulfur), as well as sulfide and sulfate minerals. From the biochemical point of view, sulfur is a vital element because it is a constituent of enzymes and other key proteins. In addition to modern uses of minerals, in old Iranian documents of traditional medicine, attention was paid to physico-chemical properties of minerals and the various methods of administration. In this review, the traditional usage of sulfur and sulfide minerals (e.g. orpiment, realgar and stibnite) and sulfate minerals (e.g. alum, jarosite, epsomite and melanterite) as documented in the Canon of Medicine of Avicenna (also known as Ibn Sina) and the Zakhireh Kharazmshahi of Jorjani, is compared with new findings about the advantages and disadvantages of these minerals in medical geology. The main conditions for the selection of mineral drugs was described first by Avicenna. There is a high correlation between old and modern pharmaceutical practices. The most important results concern the application of alum as a hemostatic agent (to inhibit hemorrhages), the use of jarosite as a method for treating osteoarthritis, the choice of melanterite for treating eczema, killing insects and as an anti-bacterial agent, the use of epsomite as an active ingredient in laxatives, homeostatics and mineral supplements, and the extensive use of sulfur in dermatology for its keratolytic effects and its supposed anti-microbial effects. In this review, newly developed pharmaceutical information about the use and effects on health of sulfide minerals will be compared to traditional pharmaceutical applications.

scholarly journals New Developments in Medical Applications of Hybrid Hydrogels Containing Natural Polymers

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1539 ◽  
Author(s):  
Cornelia Vasile ◽  
Daniela Pamfil ◽  
Elena Stoleru ◽  
Mihaela Baican
Keyword(s):  
Biomedical Applications ◽  
Chemical Properties ◽  
Synthetic Polymers ◽  
Point Of View ◽  
Natural Polymers ◽  
New Developments ◽  
Organic Hybrid ◽  
Hybrid Hydrogels ◽  
Physico Chemical ◽  
Polymeric Hydrogels

New trends in biomedical applications of the hybrid polymeric hydrogels, obtained by combining natural polymers with synthetic ones, have been reviewed. Homopolysaccharides, heteropolysaccharides, as well as polypeptides, proteins and nucleic acids, are presented from the point of view of their ability to form hydrogels with synthetic polymers, the preparation procedures for polymeric organic hybrid hydrogels, general physico-chemical properties and main biomedical applications (i.e., tissue engineering, wound dressing, drug delivery, etc.).

scholarly journals Viscosity Approximation of PDMS Using Weibull Function

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6060
Author(s):  
Andrzej Chmielowiec ◽  
Weronika Woś ◽  
Justyna Gumieniak
Keyword(s):  
Dynamic Viscosity ◽  
Chemical Properties ◽  
High Viscosity ◽  
Point Of View ◽  
Accurate Estimation ◽  
Weibull Function ◽  
Damping Factor ◽  
Dissipation Process ◽  
Physico Chemical ◽  
The Relationship

The viscosity of a fluid is one of its basic physico-chemical properties. The modelling of this property as a function of temperature has been the subject of intensive studies. The knowledge of how viscosity and temperature variation are related is particularly important for applications that use the intrinsic friction of fluids to dissipate energy, for example viscous torsional vibration dampers using high viscosity poly(dimethylsiloxane) as a damping factor. This article presents a new method for approximating the dynamic viscosity of poly(dimethylsiloxane). It is based on the three-parameter Weibull function that far better reflects the relationship between viscosity and temperature compared with the models used so far. Accurate mapping of dynamic viscosity is vitally important from the point of view of the construction of viscous dampers, as it allows for accurate estimation of their efficiency in the energy dissipation process.

scholarly journals Characterization and physico-chemical analysis of essential oil of Cymbopogon citratus leaves

2018 ◽  
Vol 11 (1) ◽  
pp. 74-81
Author(s):  
R.F. Olayemi ◽  
I.O. Jawonisi ◽  
J.A. Samuel
Keyword(s):  
Chemical Analysis ◽  
Essential Oil ◽  
Essential Oils ◽  
Chemical Properties ◽  
Acid Value ◽  
Industrial Applications ◽  
Point Of View ◽  
Gas Chromatography Mass Spectrometry ◽  
Cymbopogon Citratus ◽  
Physico Chemical

The genus Cymbopogon is important from the point of view of their essential oils. Essential oils from these species are widely used in flavours, fragrances, cosmetics, soaps, detergents and perfumery owing to their typical lemon-like aroma. Essential oil of Cymbopogon citratus was extracted by hydrodistillation and characterized using Gas chromatography/mass spectrometry (GC-MS) and Fourier Transform Infrared (FTIR).The oil was also subjected to physico-chemical analysis, the physical and chemical properties evaluated were Boiling point (74oC), Specific gravity (0.8960), Refractive index (1.4838) and pH (6.00) at 25oC. Saponification value(109.76) and Acid value (0.55) mg KOH/g oil. Iodine value (100g of I2/g oil) 105, Ester value (189.21), Residue on evaporation (10%) at 100oC.The chemical composition of the essential oil analyzed by GC-MS showed citral (31.1%), β-Myrcene (14.2%), citronellal  (9.8%), limonene  oxide (7.7%), eraniol (7.3%) and linalool (6.2%) as the major compounds. The FTIR spectra revealed the presence of n-alkane, conjugated alkene, primary amide, amine, aldehyde, primary and secondary alcohols. The results obtained from the physico-chemical parameters, and functional groups identified by FTIR as well as the compounds identified by GC-MS revealed that the oil has medicinal and nutritive values as well as industrial applications in the pharmaceutical, perfumery and cosmetic industries .Keywords: Characterization, Citral, Cymbopogon citratus, Essential oil, FTIR, GC-MS

scholarly journals Application of Auricularia cornea as a Pork Fat Replacement in Cooked Sausage

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1432
Author(s):  
Yuan Fu ◽  
Long Zhang ◽  
Mengdi Cong ◽  
Kang Wan ◽  
Guochuan Jiang ◽  
...  
Keyword(s):  
Water Activity ◽  
Chemical Properties ◽  
Point Of View ◽  
Sensory Characteristics ◽  
Isoleucine Leucine ◽  
Physico Chemical ◽  
Pork Fat ◽  
Arachidonic Acids ◽  
Water Holding ◽  
Ac Led

The effect of Auricularia cornea (AC) as an alternative for pork fat on the physico-chemical properties and sensory characteristics of cooked sausage were evaluated. The results indicated that replacement of pork fat with AC led to a significant increase in the protein, ash, moisture, cooking loss, water holding capacity, springiness, and chewiness, especially isoleucine, leucine, proline, palmitic, palmitoleic, oleic, and arachidonic acids of the sausages. In contrast, AC reduced the level of fat (12.61%–87.56%) and energy (5.76%–56.40%) of the sausages. In addition, AC led to the mild lightness, yellowness, whiteness, and soft texture, while it did not affect the water activity of the sausages. From the sensory point of view, all sausages were judged acceptable, and the substitution of 75% of pork fat by AC exhibited best sensory characteristics. In a word, AC is a promising food to partially replace the pork fat in sausages.

scholarly journals Elaboration and Physico-Chemical Characterization of the Gibbsite Li(OH)3 Hybrid Material

2021 ◽  
Vol 11 (1) ◽  
pp. 6740-6744
Author(s):  
N. el H. Belkham ◽  
D. Benachour ◽  
A. Mehamha
Keyword(s):  
Hybrid Material ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Functional Materials ◽  
Point Of View ◽  
Physico Chemical ◽  
Physicochemical Methods ◽  
Alumina Trihydrate ◽  
Double Hydroxides

A hybrid material can be defined as a combination of two components of different chemical nature. The combination of a mineral matrix and organic matter has multiple significance. From a chemical point of view, it allows the obtaining of bi-functional materials that combine the chemical properties of their components. The development of new materials with specific properties and nanostructured Lamellar Double Hydroxides (LDHs) has been widely investigated due to their great importance. This study focuses on the development of a hybrid material consisting of a matrix of alumina trihydrate Al(OH)3 (gibbsite). Previous studies on the synthesis of suspension LDHs by lithium salts intercalation in a gibbsite matrix were examined, while the obtained samples were characterized by different physicochemical methods.

Microhardness of the Coatings Created by Anodic Oxidation of Aluminum

2013 ◽  
Vol 308 ◽  
pp. 95-100 ◽  
Author(s):  
Miroslav Gombár ◽  
Alena Vagaská ◽  
Ján Kmec ◽  
Peter Michal
Keyword(s):  
Anodic Oxidation ◽  
Chemical Properties ◽  
Quality Parameter ◽  
Point Of View ◽  
Physical Factors ◽  
Anode Current Density ◽  
Functional Coatings ◽  
Physico Chemical ◽  
Resistance To Deformation ◽  
Material Conditions

Microhardness is a basic controlled quality parameter according to functional coatings, which is linked with a number of physico-chemical properties, such as coating strength, abrasion resistance, resistance to deformation, life. Life of the coating from a diagnostic point of view is influenced by chemical, physical, technological and material conditions of the process of creating film. The paper deals with analysis of the microhardness coating created by anodic oxidation of aluminum with a direct link to the chemical and physical factors controlled by the Design of Experiments methodology at constant anode current density 2 A.dm-2.

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