Chemical Structure of Vulcanized Rubber

1939 ◽  
Vol 12 (1) ◽  
pp. 43-55
Author(s):  
J. R. Brown ◽  
E. A. Hauser
Keyword(s):  
Chemical Structure ◽  
Empirical Knowledge ◽  
Extensive Investigation ◽  
Practical Application ◽  
True Nature ◽  
Rubber Industry ◽  
Vulcanized Rubber ◽  
Metallic Salts ◽  
Other Substances

Abstract A CENTURY ago, Charles Goodyear in America and Th. Hancock in England found that the properties of crude rubber could be greatly improved by heating it with sulfur. The product resulting was more elastic, more resistant to tear and abrasion, less affected by solvents, and decidedly less thermoplastic. The treatment of rubber to give these desired properties is known generally as vulcanization and must be considered as the basis for the enormous growth of the rubber industry and the extensive use of rubber products in our everyday life. Broadly speaking, vulcanization involves the reaction, in some fashion, of sulfur with rubber. Extensive investigation has revealed other substances, such as benzoyl peroxide or polynitrobenzenes, which can transform rubber into a “vulcanized” condition. Experience has also shown that metallic salts of zinc or lead and especially certain organic compounds called “accelerators” greatly affect the rate of vulcanization, and these are favorably employed in practice. A vast amount of empirical knowledge has been gained which has greatly improved the practical application of vulcanization and the quality of rubber products, but which has failed as yet to reveal a complete picture of the true nature of the process.

The Analysis of Antioxidants and Accelerators in Rubber Compounds and Vulcanizates

1964 ◽  
Vol 37 (4) ◽  
pp. 950-972 ◽  
Author(s):  
H. Auler
Keyword(s):  
Melting Point ◽  
Quantitative Determination ◽  
Chemical Structure ◽  
Melting Point Determination ◽  
Rubber Industry ◽  
Rubber Compounds ◽  
Other Substances ◽  
Determination Methods ◽  
Point Determination ◽  
The Individual

Abstract In the rubber industry the number of accelerators and antioxidants has increased greatly in the last few years. Van Alphen even in 1956 described 154 accelerators and 87 antioxidants of different chemical structure. The detection of such a large number of materials, depending on their combination in stocks, is more or less difficult, although the detection of the presence of one or another compound often makes possible a prejudgment as to which other substances can be counted on and which cannot. Besides the chemically homogeneous accelerators and antioxidants, use is also made of mixtures as combination products. The individual components are qualitatively detectable in mixtures. Information on the type of these products is given by quantitative determination methods such as described by Zijp, Kortum, Szalai and Szöke, among others. The original substances are often chemically altered during vulcanization or later in the preparation of samples for testing; e.g., symmetrically constituted disubstitution products may split into monomers, substituents split off from the basic molecule, or reactions of various types take place which render the investigation difficult. The identification of antioxidants and accelerators received a great impetus from the application of chromatography which is of importance today as a method of separating the individual materials for subsequent physical determination methods. After Tswett has recognized decades ago the separating effect of absorption columns in the analysis of compounds of chemically similar structure, this method was used only much later for the Chromatographic investigation of rubber compounds. The earlier analytical methods in this field depend on the use of conventional methods, e.g., selective extractions and precipitation of the substances to be isolated, which are then identified in pure form by melting point determination.

scholarly journals Current Trends in Polymer Based Sensors

Chemosensors ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 108
Author(s):  
Giancarla Alberti ◽  
Camilla Zanoni ◽  
Vittorio Losi ◽  
Lisa Rita Magnaghi ◽  
Raffaela Biesuz
Keyword(s):  
Chemical Structure ◽  
Low Cost ◽  
Sensing Applications ◽  
Current Trends ◽  
Manufacturing Methods ◽  
New Devices

This review illustrates various types of polymer and nanocomposite polymeric based sensors used in a wide variety of devices. Moreover, it provides an overview of the trends and challenges in sensor research. As fundamental components of new devices, polymers play an important role in sensing applications. Indeed, polymers offer many advantages for sensor technologies: their manufacturing methods are pretty simple, they are relatively low-cost materials, and they can be functionalized and placed on different substrates. Polymers can participate in sensing mechanisms or act as supports for the sensing units. Another good quality of polymer-based materials is that their chemical structure can be modified to enhance their reactivity, biocompatibility, resistance to degradation, and flexibility.

The Chemical Structure Responsible for the Deactivating Effect of Compounds Which Protect Rubber from Deterioration by Oxygen

1951 ◽  
Vol 24 (3) ◽  
pp. 638-639
Author(s):  
Jean Le Bras ◽  
Jacques Le Foll
Keyword(s):  
Nitrogen Atom ◽  
Systematic Study ◽  
Chemical Structure ◽  
Thiol Group ◽  
Vulcanized Rubber ◽  
Thiol Form

Abstract One of the present authors has already offered evidence which indicates the existence of a deactivating effect, whereby vulcanized rubber is protected against deterioration by oxygen. This effect is evident with such compounds as mercaptobenzimidazole (I), mercaptobenzoxazole, and ethylene-bis (N,N′-phenylthiourea) (II), and the phenomenon seems to be connected in some way with the presence in the molecule of a thiol group united to a nitrogen atom under such conditions that the possible tautomerism between the thion and thiol forms (III) is probably displaced toward the thiol form. We have completed these earlier experiments by a more systematic study, which has included an examination of the influence of cyclization, the nature of the ring, and hetero atoms.

scholarly journals Ten Basic Rules of Antibody Validation

2018 ◽  
Vol 13 ◽  
pp. 117739011875746 ◽  
Author(s):  
Michael G Weller
Keyword(s):  
Practical Application ◽  
Validation Criteria ◽  
Antibody Validation ◽  
Quality Of Research

The quality of research antibodies is an issue for decades. Although several papers have been published to improve the situation, their impact seems to be limited. This publication makes the effort to simplify the description of validation criteria in a way that the occasional antibody user is able to assess the validation level of an immunochemical reagent. A simple, 1-page checklist is supplied for the practical application of these criteria.

scholarly journals COMPARISON OF BASIC MAINTENANCE CONCEPTS USING WITNESS

2021 ◽  
Vol 2021 (6) ◽  
pp. 5435-5440
Author(s):  
VLADIMIRA SCHINDLEROVA ◽  
◽  
IVANA SAJDLEROVA ◽  
Keyword(s):  
21St Century ◽  
Simulation Software ◽  
Predictive Maintenance ◽  
Maintenance Management ◽  
Practical Application ◽  
Manufactured Products ◽  
The Right ◽  
Positive Effect ◽  
Production Facilities

Maintenance is a complex, extensive and important issue in terms of its impact on the quality of manufactured products or services provided in all areas of industry. The importance of predictive maintenance for the industry in the 21st century is crucial. However, the right approach to maintenance management is often underestimated in many companies today, although it can have a very positive effect on the company’s efficiency. Using the example of a practical application, the paper includes a comparison of three main maintenance concepts – classical (reactive), planned, predictive through the simulation software Witness. Maintenance concepts are compared in terms of their ability to solve and eliminate failures that occur in production facilities during operation.

scholarly journals Upaya Perbaikan Kualitas Bahan Olah Karet Rakyat

2016 ◽  
Vol 17 (2) ◽  
pp. 43
Author(s):  
A. Husni Malian ◽  
Aman Djauhari
Keyword(s):  
Competitive Advantage ◽  
Free Trade ◽  
Raw Materials ◽  
Crumb Rubber ◽  
Rubber Industry ◽  
Farm Level ◽  
Differential Price ◽  
Inhibiting Factors

<p><strong>English<br /></strong>Nowadays, free trade mechanism will be continously implemented. Regarding those conditions, the increasing export of manufacture rubber comodities can be reach, only if they have a comparative and a competitive advantage than other exporting countries. These efforts must begin with the improvement quality of rubber raw materials at farm level by removing five main inhibiting factors such as: (1) farmers group doesn't play a role as a bussiness unit (2) the demand of quality materials of crumb rubber industry is very low; (3) the dominant of trades in the marketing of raw rubber materials; (4) there is no advantageous partnership pattern, and, (5) the mechanism of attractive differential price for better quality not available for unsmoked sheet and slice slap.</p><p> </p><p><strong>Indonesian<br /></strong>Dalam era perdagangan bebas yang akan terus bergulir, peningkatan ekspor produk karet olahan hanya dapat ditempuh bila memiliki keunggulan komparatif dan kompetitif dari negara pesaing. Upaya kearah itu harus dimulai dari perbaikan kualitas bokar di tingkat petani, dengan menghilangkan lima faktor penghambat utama yaitu: (1) belum berperannya kelompok tani sebagai unit bisnis, (2) permintaan bahan baku inustri karet remah yang masih berorientasi kepada bokar berkualitas rendah, (3) dominasi pedagang dalam pemasaran bokar, dan (4) belum adanya pola kemitraan yang saling menguntungkan, (5) belum terlaksananya penentuan harga sesuai kualitas yang menarik bagi produk sheet angin dan slab giling.</p>

scholarly journals Percepcja i projekcja krajobrazu: teorie, zastosowania, oczekiwania = Perception and projection of the landscape: theories, applications, expectations

2019 ◽  
Vol 91 (3) ◽  
pp. 365-384
Author(s):  
Tadeusz Jan Chmielewski ◽  
Szymon Chmielewski ◽  
Agnieszka Kułak
Keyword(s):  
Scientific Work ◽  
Research Field ◽  
Practical Application ◽  
Landscape Perception ◽  
Knowledge Based ◽  
Space Projection ◽  
Surrounding Space ◽  
New Research ◽  
Opening Up

The human species transforms the landscape to meet its needs, but landscape resources and valuable features at the same time affect wellbeing in the context of human activity. In these mutually conditioned interactions, two processes playing a key role are the so-called landscape perception and landscape projection. This article presents: (1) a review of theories playing a key role in the development of knowledge on landscape perception; (2) the basis for landscape projection as a logical and creative continuation of perception processes; (3) an outline of the theory of physiognomic landscape structure and of possibilities for it to gain practical application; (4) the results of the first Polish research into the public’s expectations where quality of the landscape is concerned. Perception of the landscape entails the receipt of stimuli from surrounding space with the help of the senses. It serves primarily in knowledge-based transformation of landscape systems, in a manner that meets ever-more exacting requirements on the part of society when it comes to living in an environment of the highest quality. Only a little scientific work has been devoted to the process of landscape projection. This is therefore a new research field, just opening up, which has the potential to give rise to a group of space-projection theories.

The Use of Factice in Rubber Manufacture

1936 ◽  
Vol 9 (4) ◽  
pp. 621-625 ◽  
Author(s):  
E. H. Hurlston
Keyword(s):  
Early History ◽  
Intrinsic Properties ◽  
Rubber Content ◽  
High Quality ◽  
Rubber Industry ◽  
History Of

Abstract The two main classes of vulcanized oil substitute or factice are heat-cured brown factice and cold-cured white factice. They were both introduced into the rubber industry at about the same time (1846–1847), the former variety by Anderson and the latter by Parkes. It has been stated (Twiss, Trans. Inst. Rubber Ind., 7, 234 (1931)) that Parkes first opened a proofing factory at Birmingham but that the business was shortly afterwards absorbed by Chas. Macintosh & Co. and transferred to Manchester. This probably dates the commencement of the use of white factice in proofings. The early history of the development of the use of brown factice on a works scale is more obscure. As the name implies, these vulcanized oils were used in the first place as ingredients which could economically substitute part of the crude rubber content of mixings, but as time went on it became apparent to compounders that these materials possessed intrinsic properties which made them almost indispensable in certain mixings, both for ease of manufacture and for high quality of the resultant article. The utility of factices in the general rubber trade is therefore in many respects analogous to that of reclaimed rubbers.

Method of numerical estimating aerial images indicators quality for mapping purposes

2021 ◽  
Vol 968 (2) ◽  
pp. 29-37
Author(s):  
I.A. Anikeeva
Keyword(s):  
Random Noise ◽  
Experimental Studies ◽  
Aerial Images ◽  
Practical Application ◽  
Correct Color ◽  
Numerical Assessment ◽  
Airborne Imaging ◽  
Imaging Sensors ◽  
Color Rendering

The task of assessing the quality of aerial imagery, obtained for mapping, in terms of vision properties, is very ambiguous due to the lack of objective criteria and evaluation methods. A system of indicators for aerial images quality and methods of their numerical assessment is presented. The fine aerial image’s quality is characterized by a set of its structural and gradation properties. The structural properties of the image are determined by the actual spatial resolution and photographic sharpness. Gradation properties of an image are characterized by the correct color rendering, the level of random noise and information completeness indicators – haze, radiometric resolution and the percentage of information loss in illumination and shadows.Methods of evaluating these indicators are formulated, and their recommended and acceptable numerical values are determined analytically. To clarify and correct the obtained analytical recommended and acceptable numerical values of the image quality indicators of their practical application possibility and further experimental studies are necessary with materials, obtained through various airborne imaging sensors for mapping.

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