A Study on Heat History of Organic Accelerators in Rubber Stock (BR Base)

1970 ◽  
Vol 43 (4) ◽  
pp. 799-828
Author(s):  
I. Imase
Keyword(s):  
The Other ◽  
Frictional Heat ◽  
Rubber Matrix ◽  
Rubber Compound ◽  
Incremental Effect ◽  
Rubber Compounds ◽  
History Of ◽  
Curing Agents ◽  
Heat History ◽  
Rubber Stock

Abstract Rubber with some exceptions must generally undergo such processes as mastication, mixing, warming-up, extrusion, spreading, calendering, etc. prior to vulcanization under heat to obtain cured articles. Consequently the rubber matrix receives a heat history caused by mechanical frictional heat or the heat which cannot be avoided during these processes. On the other hand, when an uncured rubber compound, ready for vulcanization, containing such curing agents as sulfur, such activators as zinc oxide, and organic accelerators is heated during the processes or during storage between individual processes, each incremental effect of heat is accumulated with time. It is a well-known fact that this accumulation of heat can lead to the trouble of scorching, etc. As a cause for the trouble, organic accelerators seem to play the most important role. A few reports have been published on the action of accelerators under heat, but, to my knowledge, no report is available on the behavior of accelerators in rubber stocks, namely, on the change of the properties of uncured rubber compounds and on its influence on the properties of vulcanizates. This paper shall report these problems, though it describes only the results of the tests carried out under specific conditions.

INFLUENCE OF MASTICATION ON THE MICROSTRUCTURE AND PHYSICAL PROPERTIES OF RUBBER

2021 ◽  
Author(s):  
Koji Okamoto ◽  
Michiharu Toh ◽  
Xiaobin Liang ◽  
Ken Nakajima
Keyword(s):  
Physical Properties ◽  
Elastic Moduli ◽  
Large Diameter ◽  
The Other ◽  
Rubber Matrix ◽  
Interfacial Region ◽  
Rubber Compound ◽  
Atomic Force ◽  
Rubber Compounds ◽  
Isoprene Rubber

ABSTRACT The effects of the masticated state of isoprene rubber (IR) at the carbon black (CB) addition stage on subsequent mixing, microstructure, and physical properties in the case of a kneader with a characteristic large-diameter shaft are investigated by examining the mastication-time dependence. A sufficiently masticated IR shows a shorter black incorporation time, which results in an improved dispersion of CB and better physical properties. Observing the microstructure of a rubber compound using the atomic force microscope–based nanomechanical technique, poor CB dispersion is revealed for insufficient mastication. Specifically, large CB agglomerations surrounded by the interfacial rubber region with higher elastic modulus than that of a rubber matrix are formed. Such a large CB agglomeration, on the other hand, does not appear in rubber compounds with longer mastication times. The thickness of the interfacial region becomes shorter in these cases. These observations are further discussed by the concept of “rheological unit” introduced by Mooney et al. This study demonstrates that the microstructure of a rubber compound is highly heterogenous with rubber regions of different microscopic elastic moduli and that the microstructure has an influence on CB dispersion and the physical properties of rubber.

Fiber Adhesion to Rubber Compounds

2008 ◽  
Vol 81 (3) ◽  
pp. 523-540 ◽  
Author(s):  
W. B. Wennekes ◽  
R. N. Datta ◽  
J. W. M. Noordermeer ◽  
F. Elkink
Keyword(s):  
Plasma Treatment ◽  
Fiber Surface ◽  
Surface Roughening ◽  
Rubber Compound ◽  
Rubber Composites ◽  
Adhesion Promoter ◽  
Rubber Compounds ◽  
Polyester Fibers ◽  
History Of ◽  
Fiber Materials

Abstract The present paper provides an overview of literature published on fiber-rubber composites. A brief history of Fibers used in rubber applications is given. The emphasis is on the adhesion between fiber materials and rubber compounds. Special attention is given to the standard RFL-treatment and the double-dip treatment used for aramid and polyester Fibers to enhance the adhesion with rubber compounds. Some alternatives to the RFL-treatment are described: fiber surface roughening, adhesion promoter additives to the rubber compound, impregnated Fibers and plasma treatment.

Method of Making Micro-Sections of Rubber Stocks

1930 ◽  
Vol 3 (4) ◽  
pp. 755-763
Author(s):  
Raymond P. Allen
Keyword(s):  
Field Work ◽  
Dark Field ◽  
The Other ◽  
Bright Field ◽  
Thin Sections ◽  
Rubber Compounds ◽  
Dark Field Illumination ◽  
Natural Belief ◽  
Rubber Stock ◽  
Highly Loaded

Abstract THE possibility of seeing pigment particles in a rubber stock has always been a desire of rubber chemists. There has been a natural belief that if the particles in rubber could actually be observed with a microscope more could be learned about their action and properties. The main difficulty in attaining this end lies in the preparation of sufficiently thin sections. For clear observation of highly loaded gas-black stocks the sections must be less than 1 micron thick. For bright-field work with light-colored or colorless pigments, such as litharge and zinc oxide, the sections may be somewhat thicker. However, if the examination is to be made with dark-field illumination the sections for even the colorless pigments must again be very thin. Several methods have been proposed and utilized for making thin sections, and the names of Dannenberg (2), Depew (3), Green (4), Grenquist (5), Hauser (7), Moore (11), Pohle (9), Ruby (3), Spear (11), and Walton (12) are identified with the skilful manipulation which is necessary for achieving the desired result. There have been many other workers in this field, including Weber (13), Breuil (1), Loewen (8), Regnaud (10), and Hardman (6). The method to be described was developed in this laboratory in 1926. It has been used continually since that time and has proved valuable in the study of rubber compounds and pigments. While it bears a slight similarity to some of the other methods, it has certain unique and distinct advantages of its own.

scholarly journals Effect Of Liquid Rubbers On The Thermal And Adhesion Properties Of The Tire Skim Compound

2021 ◽  
Vol 4 (1) ◽  
pp. 101-110
Author(s):  
Furkan Celtik ◽  
Enes Kilic ◽  
Mustafa Ozgur Bora ◽  
Ekrem Altuncu
Keyword(s):  
Mechanical Properties ◽  
Dynamic Mechanical Properties ◽  
Rubber Matrix ◽  
Hydroxyl Groups ◽  
Rubber Compound ◽  
Carboxyl Content ◽  
Adhesion Properties ◽  
Rubber Compounds ◽  
Reaction Extent ◽  
And Migration

Polymeric textile cords, steel cords and steel cables are mainly reinforcing materials that are used in tire production. Polymeric textile cords such as Polyester (PEs), Nylon, Aramid and Rayon are commonly treated with bi-functional resorcinol formaldehyde latex (RFL) to obtain desired adhesion to rubber matrix. PEs cords are known as their poor adhesion to both RFL and rubber compounds due to limited reactivity on the surface and poor reaction extent between methylol and hydroxyl groups of RFL. Increasing carboxyl content on PEs surface or in the rubber compound is one of the best strategies to overcome this adhesion problem. Liquid rubbers, which can co-vulcanize with solid rubbers, are also strong alternatives of process oils with their excellent plasticizing effect without deterioration in mechanical properties of the resulting material. Co-vulcanization also improves the stability of this additive and prevents possible bleeding and migration during service life of the tire. In this study, carboxylated grafted liquid isoprene rubber has been incorporated to rubber compound to improve adhesion in PEs-RFL-Rubber ternary system. Rheological and dynamic-mechanical properties of reactive liquid rubber containing tire rubber compounds have been evaluated extensively, as well as H-adhesion behaviour of PEs cord-rubber composite matrix.

Adhesion and Autohesion of Rubber Compounds: Effect of Surface Roughness

1995 ◽  
Vol 68 (1) ◽  
pp. 13-25 ◽  
Author(s):  
A. N. Gent ◽  
S-M. Lai
Keyword(s):  
Surface Roughness ◽  
Smooth Surface ◽  
Peel Strength ◽  
The Other ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Roughened Surface ◽  
Styrene Butadiene ◽  
Effect Of Surface ◽  
Strength Of Adhesion

Abstract Sheets of various rubber compounds were pre-molded using different mold surfaces: Mylar film, smooth steel, and roughened steel. Two sheets of the same compound were then bonded together by crosslinking them in contact. Measurements of peel strength were carried out over a range of temperatures from −40°C to + 130°C. When an uncured sheet was crosslinked in contact with a smooth fully-cured sheet, the peel strength was generally lower than the tear strength of either sheet and the degree of interlinking was inferred to be only about one-half of the degree of crosslinking. On the other hand, when a sheet was cured in contact with a rough surface the strength of adhesion was 2× to 3× higher than with a smooth surface, probably because of increased area for bonding. Thus, when a rubber compound was cured in contact with a fully-cured sheet having a roughened surface, the two effects largely cancelled out and the resultant bond was about as strong as the material itself. Examples are given for carbon-black-filled and unfilled compounds based on polybutadiene, a styrene-butadiene copolymer, and natural rubber.

Influence of Curing Agents on Rubber-to-Textile and Rubber-to-Steel Cord Adhesion

1973 ◽  
Vol 46 (4) ◽  
pp. 981-998 ◽  
Author(s):  
K.-D. Albrecht
Keyword(s):  
The Other ◽  
Complete Wetting ◽  
Bonding Agents ◽  
Pull Out ◽  
Steel Cord ◽  
Sulfur Level ◽  
Curing Agents ◽  
Reinforcing Material ◽  
Heat History ◽  
Pull Out Strength

Abstract The results presented in this paper show that the dosage of sulfur greatly influences rubber-to-textile and rubber-to-steel cord adhesion. As far as rubber-to-textile adhesion is concerned, the pull-out strength is reduced when the sulfur level falls below 2 phr, the extent of the reduction depending on the type of fiber and the bonding process. With steel cord the lower limit for sulfur is as high as 3 phr. This is discouraging because it shows that the use of efficient and semi-efficient vulcanization in the manufacture of goods reinforced with fabrics or steel cord is, to say the least, highly problematical. On the other hand, it is often desirable to reduce the proportion of sulfur in order, for instance, to increase resistance to aging and reversion and to reduce compression set and heat build-up. The choice of accelerators also has an important influence on adhesion. A sufficiently long scorch time is required to allow complete wetting of the reinforcing material by the rubber compound. If curing starts before complete wetting of the textile or steel cord has occurred, adhesion cannot be built up. For example, unsatisfactory or no rubber-to-textile and rubber-to-steel cord adhesion is obtained, when ultra-accelerators are used. As the scorch time increases, adhesion improves. Best results are obtained with sulfenamides, but sulfenamides showing increasing scorch time give no improvement in rubber-to-textile bonding. However, DCBS gave much better results for rubber-to-steel cord adhesion than the other sulfenamides and thus appears particularly suitable. Although the results given by the other sulfenamides can be somewhat improved by the addition of a retarder, pull-out strength values do not reach those given by DCBS. Any decrease of scorch time of a compound deteriorates adhesion whether scorch time is reduced by compounding ingredients or by heat history imposed by processing. MBI, used as an antioxidant, which reduces scorch time drastically, causes complete loss of rubber-to-steel cord adhesion and also impairs rubber-to-textile adhesion. Most of the antioxidants, however, have a beneficial effect on mbber-to-steel cord adhesion. For zinc-plated steel cord antioxidants of the amine type give results inferior to those of the phenolic type. To obtain optimal rubber-to-textile and rubber-to-steel cord adhesion the compounder primarily has to consider the efficacy of the bonding agents but in addition he has to take into account the effects which may be exerted by compounding ingredients and processing conditions.

Sulphur and peroxide vulcanisation of rubber compounds – overview

2016 ◽  
Vol 70 (12) ◽  
Author(s):  
Ján Kruželák ◽  
Richard Sýkora ◽  
Ivan Hudec
Keyword(s):  
Network Structure ◽  
Reaction Mechanisms ◽  
Three Dimensional ◽  
Rubber Matrix ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Carbon Carbon Bonds ◽  
Peroxide Curing ◽  
Cross Links ◽  
The Cross

AbstractVulcanisation is a process of transforming a plastic rubber compound into a highly elastic product by forming a three-dimensional cross-linked network structure in the rubber matrix. Many systems have been developed to vulcanise rubber compounds, among which sulphur and peroxide curing systems remain the most desirable. The application of sulphur systems leads to the forming of sulphidic cross-links between elastomer chains, while carbon–carbon bonds are formed in peroxide-curing. Both vulcanisation systems provide certain benefits to the cross-linked rubber articles, but also some disadvantages. The present work seeks to provide an overview on both vulcanisation systems; their composition, possibilities of their application, reaction mechanisms, structure of the cross-links formed and the main feature of the final cross-linked materials – vulcanisates.

VULCANIZATION OF RUBBER COMPOUNDS WITH PEROXIDE CURING SYSTEMS

2017 ◽  
Vol 90 (1) ◽  
pp. 60-88 ◽  
Author(s):  
Ján Kruželák ◽  
Richard Sýkora ◽  
Ivan Hudec
Keyword(s):  
Three Dimensional ◽  
Rubber Matrix ◽  
Cross Linking ◽  
Rubber Compounds ◽  
Dimensional Network ◽  
Fundamental Goal ◽  
Cross Links ◽  
Curing Agents ◽  
Curing Systems

ABSTRACT Vulcanization or curing is one of the most important processes in rubber technologies. During this process, plastic rubber compounds by parallel and subsequent physical and mainly chemical reactions change into highly elastic products—vulcanizates. The fundamental goal of curing is forming chemical cross-links between rubber macromolecules, which leads to the formation of a three-dimensional network or rubber matrix. A number of curing systems have been introduced in cross-linking of elastomers; each system has its own characteristics and composition; therefore, vulcanizates with different properties also can be prepared. We characterize organic peroxides as curing agents and their decomposition mechanisms and characteristics and bring a detailed view to understanding mechanisms between peroxides and different types of rubber matrices. Then, we focus on the classification and characterization of co-agents used in peroxide cross-linking and explain the mutual interactions and reaction mechanisms between peroxide, co-agents, and rubber matrices in relation to the properties of prepared materials. Finally, the drawbacks and the main features of final cross-linked materials are outlined.

Theodor W. Adorno

2018 ◽  
Author(s):  
Colby Dickinson
Keyword(s):  
The Other ◽  
History Of Thought ◽  
History Of ◽  
The One

In his somewhat controversial book Remnants of Auschwitz, Agamben makes brief reference to Theodor Adorno’s apparently contradictory remarks on perceptions of death post-Auschwitz, positions that Adorno had taken concerning Nazi genocidal actions that had seemed also to reflect something horribly errant in the history of thought itself. There was within such murderous acts, he had claimed, a particular degradation of death itself, a perpetration of our humanity bound in some way to affect our perception of reason itself. The contradictions regarding Auschwitz that Agamben senses to be latent within Adorno’s remarks involve the intuition ‘on the one hand, of having realized the unconditional triumph of death against life; on the other, of having degraded and debased death. Neither of these charges – perhaps like every charge, which is always a genuinely legal gesture – succeed in exhausting Auschwitz’s offense, in defining its case in point’ (RA 81). And this is the stance that Agamben wishes to hammer home quite emphatically vis-à-vis Adorno’s limitations, ones that, I would only add, seem to linger within Agamben’s own formulations in ways that he has still not come to reckon with entirely: ‘This oscillation’, he affirms, ‘betrays reason’s incapacity to identify the specific crime of Auschwitz with certainty’ (RA 81).

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