Science and Technology of Reclaimed Rubber

1967 ◽  
Vol 40 (1) ◽  
pp. 217-237 ◽  
Author(s):  
D. S. le Beau
Keyword(s):  
Natural Rubber ◽  
Polymer Processing ◽  
Raw Material ◽  
Plastic State ◽  
Substantial Part ◽  
Process Conditions ◽  
Fibrous Materials ◽  
The Past ◽  
Synthetic Rubber ◽  
Mechanical Handling

Abstract Developments in the rubber reclaiming industry are closely related to those in the rubber industry in general. The vulcanized rubber produced by the latter becomes in time the raw material used by the former. Although not superficially obvious, there has been considerable change in the reclaiming industry in the past two decades, required by the introduction of large proportions of synthetic rubber. Since this occurs both alone and in blends with natural rubber, reclaiming of SBR had to be studied in detail so that processes could be adjusted to give approximately the same viscosity from synthetic rubber and from natural, retaining existing procedures for fiber removal and mechanical handling as much as possible. It would have been economically impossible for reclaimers to use any process which required segregation and separate disposal of a substantial part of their raw material. The machinery used in the production of reclaim, and the reclaiming processes used today, are for the major part still the same as used before. The object of reclaiming vulcanized scrap is still the same, i.e., the breakdown (depolymerization) of the scrap to a plastic state which will permit reuse of it in the current rubber processing machinery for the manufacture of new goods. This breakdown is achieved by the application of energy. The type of energy is fundamentally irrelevant, but economics today dictate that it be heat, with partial exclusion of the oxidizing atmosphere, and therefore most of today's reclaim production is carried out in steam. One new continuous reclaiming process was developed during the last fifteen years which relies on electric energy to provide the necessary heat and working of the vulcanized scrap. A fundamental change in requirements of reclaim was also brought about once the synthetic rubber production had proceeded to the point where it was commercially possible to assign more detailed specifications which described the polymer processing behavior limits—a feat not previously achieved for commercial natural rubber. This type of specification was carred over to a considerable extent into the production and sale of today's reclaim. All in all, the extensive research and polymer knowledge which were acquired for the successful production of synthetic rubber have resulted in a much greater control in the production of reclaim and a much greater understanding of the reactions occurring in polymers during reclaiming. Because vulcanized scrap usually contains extraneous material (fiber) which must be removed during reclaiming the process conditions have in the past been selected primarily to accomplish this removal and were not those best suited for the actual reclaiming reaction. Progress has been made during these last years in removing the fibrous materials before reclamation, thereby permitting conditions in the devulcanization cycle to be determined by the actual needs of the vulcanized scrap.

Qualitative Spot Tests for Rubber Polymers

1946 ◽  
Vol 19 (3) ◽  
pp. 832-843 ◽  
Author(s):  
H. P. Burchfield
Keyword(s):  
Natural Rubber ◽  
Filter Paper ◽  
Raw Material ◽  
Color Changes ◽  
Synthetic Rubber ◽  
Large Numbers ◽  
Confirmatory Tests ◽  
Commercially Important ◽  
Spot Tests ◽  
Representative Samples

Abstract To eliminate processing difficulties and ensure the production of standard natural and synthetic rubber reclaims, the scrap used as the raw material must be carefully segregated. When mold markings are lost, or large consignments of miscellaneous scrap are received, methods for distinguishing between the basic polymers are necessary. This paper describes a new color reaction which will serve to characterize natural rubber, GR-S, and Perbunan. Confirmatory tests included in the same operation distinguish between the remaining commercially important types. The procedure is sufficiently rapid to be practical in the testing of representative samples from carload shipments, or for establishing the identity of materials on which indecisive results are obtained by less specific methods. For the routine assortment of scrap, spot tests are proposed, which are carried out by holding impregnated filter paper strips in the smoke emitted when the sample is branded with a metal rod heated to redness. Color changes take place which indicate the nature of the polymer. One test distinguishes between natural rubber and GR-S ; a second is specific for Butyl ; a third differentiates Neoprene-GN, Neoprene-ILS, and Perbunan from one another and from the hydrocarbon rubbers. The spot reactions can be carried out very rapidly, and are particularly useful when large numbers of samples must be examined.

Flex Life and Crystallization of Synthetic Rubber

1944 ◽  
Vol 17 (2) ◽  
pp. 398-403 ◽  
Author(s):  
J. H. Fielding
Keyword(s):  
Natural Rubber ◽  
Experimental Work ◽  
Thermal Effects ◽  
X Ray ◽  
The Past ◽  
Synthetic Rubber ◽  
New Material ◽  
The Subject ◽  
And Performance ◽  
Ray Patterns

Abstract The crystalline structure of stretched natural rubber has been the subject of much experimental work in the past. A great deal of this has been devoted to the more theoretical aspects, such as x-ray patterns, thermal effects, and volume change. It is now known that neither Buna-N nor GR-S has a fiber diagram when stretched and that Butyl-B and Neoprene do have such patterns. Since the industry is now in the process of changing from natural rubber to GR-S, it is of interest to see just what this lack of crystallinity means from a compounding and performance standpoint. It is possible that many of our ideas based on rubber must change, that GR-S must be considered to be a new material, and that radical changes in formulation and construction must be made.

Fun and Frustrations with Synthetic Rubber

1977 ◽  
Vol 50 (3) ◽  
pp. 67-77
Author(s):  
James D. D'Ianni
Keyword(s):  
World War Ii ◽  
Natural Rubber ◽  
Korean War ◽  
American Chemical Society ◽  
Chemical Society ◽  
World War ◽  
Great Pleasure ◽  
The Past ◽  
Synthetic Rubber ◽  
The Korean War

Abstract It is a great pleasure and honor to have this opportunity to share with you some of my experiences in synthetic rubber over the past forty years. I am deeply appreciative of my selection as the thirty-fourth recipient of the Charles Goodyear Medal by the Rubber Division of the American Chemical Society and accept it only as a representative of my many associates at Goodyear who have participated with me in significant developments in synthetic rubber during this period. As the title of this talk indicates, we had both successes and disappointments in our endeavors to develop improved synthetic rubbers. These efforts were greatly stimulated by shortages of natural rubber which occurred in times of national emergencies such as World War II and the Korean War. When we successfully met these challenges it was fun, but to the extent that we were not able to achieve all of our objectives, we suffered a number of frustrations.

Ski Rubber, a New Polyisoprene

1958 ◽  
Vol 31 (1) ◽  
pp. 44-48
Author(s):  
S. A. Subbotin ◽  
V. V. Samoletova ◽  
A. K. Znamenskaya
Keyword(s):  
Natural Rubber ◽  
Chemical Nature ◽  
General Purpose ◽  
Raw Material ◽  
Practical Application ◽  
Synthetic Rubber ◽  
Industrial Synthesis ◽  
Truck Tires ◽  
Isoprene Rubber

Abstract It is known that the industrial synthesis of general purpose rubbers has been accomplished and has been developing on the basis of the use of divinyl as the starting monomer, taken either in the pure state (sodium-divinyl rubber) or in mixture with another monomer—styrene (divinylstyrene rubber). However, synthetic polymers of isoprene have, to this day, found no practical application despite the fact that natural rubber (NR) is a polyisoprene and the first samples of synthetic rubber were obtained from isoprene. This is explained by the circumstance that, up to the present time, it was not possible to synthesize an isoprene or a copolymer-isoprene rubber which would have substantially improved properties over a similar rubber obtained on the base of divinyl; in addition isoprene is a less plentiful raw material than divinyl. Divinyl rubbers differ from natural rubber not only in their microstructure but also in the chemical nature of the link of the polymer chain; and still, with time, they successfully replaced natural rubber in the production of a large number of rubber goods. At the same time, due to various new properties possessed by the divinyl rubbers, their application led to the improvement in the quality of certain goods and, in many cases, to a simplification and reduction in cost of production of the latter. Nevertheless even the most modern general purpose commercial rubbers, which are obtained from divinyl, possess various substantial shortcomings in comparison with natural rubber. The most significant shortcoming of the divinyl rubbers is their reduced elasticity. This shortcoming is especially significant all the more, since rubber mixes with these rubbers as a base must, because of their low strength, be prepared with a large content of carbon black. For this reason such rubbers cannot serve as an equivalent substitute for natural rubber in carcass and breaker rubbers for tires, especially truck tires, and in the manufacture of various technical and also household, highly elastic goods.

INNOVATIONS EQUIPMENT FOR DETERMINING CAPILLARITY OF FIBROUS MATERIALS FOR CLOTHES

2019 ◽  
pp. 388-394
Author(s):  
Sergei Pryvalа ◽  
Valeriy Pryvala ◽  
Anna Malovanа
Keyword(s):  
Chemical Compounds ◽  
World Market ◽  
Comprehensive Analysis ◽  
Raw Material ◽  
Fibrous Materials ◽  
Textile Materials ◽  
The Past ◽  
Literary Sources ◽  
The World ◽  
Physical And Chemical

Modern textile materials entering the world market do not always correspond to those physical, mechanical and hygienic characteristics, which are indicated in the corresponding accompanying documentation. This creates considerable difficulties in the manufacture of sewing products of various purposes and, most importantly, affects their final quality and service life. In this regard, there is a need for a comprehensive check of modern textile materials to meet the necessary level of their operational properties. For example, one of the most important indicators of hygiene of textile materials is their ability to interact with liquids, such as water or its chemical compounds. Analysis of literary sources showed that the least technically secured is the technique of studying the capillarity of materials, that is, their ability to raise the liquid with fibers at a certain height. This is due to the fact that the specified physical and chemical process is difficult to study, because it is associated with many indicators of materials: the type of their interweaving, thickness, raw material content, the size of fibers, the type of decoration, etc. This article provides a comprehensive analysis of existing techniques and techniques for the study of capillarity over the past 30 years. In particular, existing and projected special devices are considered, the basis of which is the principle of interaction of the experimental material and the column of liquid. In addition, contemporary developments of the Ukrainian scientists in this area are proposed for consideration, the achievements of which have been confirmed by their patentability and official acts of tests.

scholarly journals Butadiene Rubber in the Petrochemical Industry

2021 ◽  
Vol 11 (1) ◽  
pp. 22-26
Author(s):  
Abdulaziz K Bubshait
Keyword(s):  
Natural Rubber ◽  
Petrochemical Industry ◽  
Oil Prices ◽  
Global Market ◽  
Raw Material ◽  
Agricultural Product ◽  
Butadiene Rubber ◽  
Global Business ◽  
Synthetic Rubber ◽  
Rubber Market

The Butadiene is a raw material used in the petrochemical industry. The use of Butadiene has risen with petrochemical market growth. The Global market is forecasting a demand growth for butadiene applications, especially for rubber materials. The estimated synthetic rubber market is $19.1 billion in 2021 and forecasted to reach $23.2 billion in five years. The dynamic growth in butadiene applications will introduce new products used in many things from the food industry to sports and goods. Also, the rubber materials have different applications in the automotive industry, oil and gas, medical products, and plastics. Companies’ strategic planning to increase the production of synthetic rubber for the global market. The demand increased as new applications were introduced to the market. The stability of oil prices will have the rubber market steady which always leads to optimal pricing. The diver for Butadiene rubber applications is to maximize production by having different kind of materials that applied for several products. The global business development indicated the ability to increases the synthetic rubber market rubber and capacities, which will enhance the chemical process techniques, new technology design, and efficiency that will maximize production and minimize product cost. Looking into the price difference between synthetic and natural rubber, many fluctuation variables were introduced in the price of each type. For example, synthetic rubber price is high, depending on crude oil, natural gasoline and naphtha prices, since those feedstocks are fed to the cracking units, as C4 is one of the cracking products. Therefore, any change in the oil prices will influence the butadiene price, which is the feed for most rubber plants. In addition, the utilities required for those plants to operate have a major impact on overall price. On the other hand, Natural rubber is an agricultural product and dependent on soil type and weather.

RHEOLOGICAL PROPERTIES OF CERAMIC MASSES: IMPROVEMENT BY COMPLEX MATERIAL ACTIVATION

2019 ◽  
Vol 16 (3) ◽  
pp. 334-351
Author(s):  
A. S. Mavlyanov ◽  
E. K. Sardarbekova
Keyword(s):  
Rheological Properties ◽  
Raw Materials ◽  
Sensitivity Coefficient ◽  
Raw Material ◽  
Clay Material ◽  
Fibrous Materials ◽  
Chemical Production ◽  
Production Wastes ◽  
Pass Through ◽  
The Masses

Introduction. The objective of the research is to study the effect of the complex activation of the alumina raw material on the rheological properties of the ceramic mass. In addition, the authors investigate solutions for the application of optimal coagulation structures based on loams and ash together with plastic certificates.Materials and methods. The authors used the local forest like reserves of clay loams at the BashKarasu, ash fields of the Bishkek Central Heating Centre (BTEC) and plasticizer (sodium naphthenate obtained from alkaline chemical production wastes) as fibrous materials. Moreover, the authors defined technological properties of raw materials within standard laboratory methodology in accordance with current GOSTs.Results. The researchers tested plastic durability on variously prepared masses for the choice of optimal structures. The paper demonstrated the plastic durability of complexly activated compounds comparing with non-activated and mechanically activated compounds. The sensitivity coefficient increased the amount of clay loams by mechanically and complexly activated, which predetermined the possibility of intensifying the process of drying samples based on complexly activated masses.Discussion and conclusions. However, mechanical activation of clay material reduces the period of relaxation and increases the elasticity coefficient of ceramic masses by 1.8–3.4 times, meanwhile decreases elasticity, viscosity and the conventional power during molding, which generally worsens the molding properties of the masses. Сomplex activation of ash-clay material decreases the period of relaxation and provides an increase in elasticity, plasticity of ceramic masses by 46–47%, reduction in viscosity by 1.5–2 times, conventional power on molding by 37–122% in comparison with MA clay loams. Ceramic masses based on spacecraft alumina raw materials belong to the SMT with improved rheological properties; products based on them pass through the mouthpiece for 5–7 seconds.

scholarly journals Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2237 ◽  
Author(s):  
P. R. Sarika ◽  
Paul Nancarrow ◽  
Abdulrahman Khansaheb ◽  
Taleb Ibrahim
Keyword(s):  
Raw Materials ◽  
Phenol Formaldehyde ◽  
Raw Material ◽  
Wood Industry ◽  
Suitable Material ◽  
The Past ◽  
Wide Range ◽  
Recent Developments ◽  
Sustainable Materials ◽  
Materials Used

Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.

scholarly journals Utilization of Cumbeba (Tacinga inamoena) Residue: Drying Kinetics and Effect of Process Conditions on Antioxidant Bioactive Compounds

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 788
Author(s):  
João Paulo de Lima Ferreira ◽  
Alexandre José de Melo Queiroz ◽  
Rossana Maria Feitosa de Figueirêdo ◽  
Wilton Pereira da Silva ◽  
Josivanda Palmeira Gomes ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Bioactive Compounds ◽  
Fixed Bed ◽  
Drying Kinetics ◽  
Raw Material ◽  
Process Conditions ◽  
Temperature Range ◽  
Water Diffusivity ◽  
Pharmaceutical Industries ◽  
Effective Water

The residue generated from the processing of Tacinga inamoena (cumbeba) fruit pulp represents a large amount of material that is discarded without proper application. Despite that, it is a raw material that is source of ascorbic acid, carotenoids and phenolic compounds, which are valued in nutraceutical diets for allegedly combating free radicals generated in metabolism. This research paper presents a study focused on the mathematical modeling of drying kinetics and the effect of the process on the level of bioactive of cumbeba residue. The experiments of cumbeba residue drying (untreated or whole residue (WR), crushed residue (CR) and residue in the form of foam (FR)) were carried out in a fixed-bed dryer at four air temperatures (50, 60, 70 and 80 °C). Effective water diffusivity (Deff) was determined by the inverse method and its dependence on temperature was described by an Arrhenius-type equation. It was observed that, regardless of the type of pretreatment, the increase in air temperature resulted in higher rate of water removal. The Midilli model showed better simulation of cumbeba residue drying kinetics than the other models tested within the experimental temperature range studied. Effective water diffusivity (Deff) ranged from 6.4890 to 11.1900 × 10−6 m2/s, 2.9285 to 12.754 × 10−9 m2/s and 1.5393 × 10−8 to 12.4270 × 10−6 m2/s with activation energy of 22.3078, 46.7115 and 58.0736 kJ/mol within the temperature range of 50–80 °C obtained for the whole cumbeba, crushed cumbeba and cumbeba residue in the form of foam, respectively. In relation to bioactive compounds, it was observed that for a fixed temperature the whole residue had higher retention of bioactive compounds, especially phenolic compounds, whereas the crushed residue and the residue in the form of foam had intermediate and lower levels, respectively. This study provides evidence that cumbeba residue in its whole form can be used for the recovery of natural antioxidant bioactive compounds, mainly phenolic compounds, with the possibility of application in the food and pharmaceutical industries.

scholarly journals Bodies Out of Time: Sculpting Queer Poetics and Queering Classical Sculpture in the Poetry of C. P. Cavafy

2021 ◽  
Author(s):  
J. L. Watson
Keyword(s):  
Raw Material ◽  
Ancient Greek ◽  
Greek Poetry ◽  
Modern Greek ◽  
The Past ◽  
Greek World

AbstractTwo major themes dominate the poetry of the Alexandrian poet, C. P. Cavafy: homosexual desire and Greekness, broadly defined. This paper explores the interconnectivity of these motifs, showing how Cavafy’s poetic queerness is expressed through his relationship with the ancient Greek world, especially Hellenistic Alexandria. I focus on Cavafy’s incorporation of ancient sculpture into his poetry and the ways that sculpture, for Cavafy, is a vehicle for expressing forbidden desires in an acceptable way. In this, I draw on the works of Liana Giannakopoulou on statuary in modern Greek poetry and Dimitris Papanikolaou on Cavafy’s homosexuality and its presentation in the poetry. Sculpture features in around a third of Cavafy’s poems and pervades it in various ways: the inclusion of physical statues as focuses of ecphrastic description, the use of sculptural language and metaphor, and the likening of Cavafy’s beloveds to Greek marbles of the past, to name but three. This article argues that Cavafy utilizes the statuary of the ancient Greek world as raw material, from which he sculpts his modern Greek queerness, variously desiring the statuesque bodies of contemporary Alexandrian youths and constructing eroticized depictions of ancient Greek marbles. The very ontology of queerness is, for Cavafy, ‘created’ using explicitly sculptural metaphors (e.g. the repeated uses of the verb κάνω [‘to make’] in descriptions of ‘those made like me’) and he employs Hellenistic statues as a productive link between his desires and so-called ‘Greek desire’, placing himself within a continuum of queer, Greek men.

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