scholarly journals Fine Grinding of Vulcanized Rubber Using Kneading Equipment at High Temperature

2005 ◽  
Vol 78 (1) ◽  
pp. 3-7 ◽  
Author(s):  
Kazumasa YOSHIKAI ◽  
Michiharu TOH ◽  
Seiko HIMENO
Keyword(s):  
High Temperature ◽  
Fine Grinding ◽  
Vulcanized Rubber

scholarly journals The Fine Grinding of the Vulcanized Rubber Using the Vulcanization Method in Internal Mixers

2004 ◽  
Vol 77 (6) ◽  
pp. 200-206
Author(s):  
Michiharu TOH ◽  
Kazumasa YOSHIKAI ◽  
Seiko HIMENO
Keyword(s):  
Fine Grinding ◽  
Vulcanized Rubber

A Novel Method to Recycle Scrap Tires: High-Pressure High-Temperature Sintering

2002 ◽  
Vol 75 (5) ◽  
pp. 955-968 ◽  
Author(s):  
Jeremy E. Morin ◽  
Drew E. Williams ◽  
Richard J. Farris
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
High Temperature ◽  
Rubber Particle ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Scrap Tires ◽  
Vulcanized Rubber ◽  
High Pressure High Temperature ◽  
Styrene Butadiene

Abstract High-pressure high-temperature sintering (HPHTS) is a novel recycling technique that makes it possible to recycle vulcanized rubber powders made from waste rubber (namely scrap tires) through only the application of heat and pressure. A brief look into the mechanism of sintering will be presented along with information about the influence of molding variables, such as time, temperature, pressure and rubber particle size on the mechanical properties of the produced parts. One of the most interesting observations is that powders of every crosslinked elastomer attempted sintered together via this technique, including silicone rubber (SI), sulfur cured [natural rubber (NR), ethylene-propylene-diene rubber (EPDM), styrene-butadiene rubber (SBR)], peroxide cured butadiene rubber (BR), and fluoroelastomers (FKM). Early work on sintered rubber made from commercially available rubber powder had a modulus of 1 to 2 MPa, strength of 4 to 7 MPa and an elongation at break of 150–250%. Recently, in-house ground samples of SBR have had sintered values over 9.5 MPa strength and 275% elongation, or greater than 60% retention of the original properties. Many of these mechanical properties are comparable with industrially manufactured rubbers, and it is believed that recycled rubbers produced via HPHTS offer the potential to replace virgin rubber in numerous applications.

Effect of Temperature on Tensile Properties of Vulcanized Rubber

1934 ◽  
Vol 7 (2) ◽  
pp. 371-386
Author(s):  
A. A. Somerville ◽  
W. F. Russell
Keyword(s):  
High Temperature ◽  
Tensile Properties ◽  
Room Temperature ◽  
Point Of View ◽  
Effect Of Temperature ◽  
Curing Conditions ◽  
Vulcanized Rubber ◽  
Before And After ◽  
Temperature Test ◽  
Better Than

Abstract The tensile properties and tear resistance of a large number of commercial inner tubes, before and after aging by different methods, are studied at 0°, 25°, and 100° C. A number of uncured bus-truck tube stocks are also studied from the point of view of their capacity to withstand high temperatures. The effect of testing rubber at 100° C. as compared with room temperature is discussed; how some compounds collapse at 100° C., while others have tensile properties equal to, or better than those at 25°, is shown. The effect of testing artificially aged specimens at 100° C., as well as at 25° C., is discussed; the high-temperature test may reveal conditions of deterioration and overcure that are not noticeable in the 25° tests. The compounding and curing conditions that lead to high tensile properties at 100° C., as well as those which cause inferior quality, are discussed.

Effects of Thermal Cycling on Elastomers in High Temperature Coolant

2010 ◽  
Author(s):  
Daniel L. Hertz
Keyword(s):  
High Temperature ◽  
Thermal Cycling ◽  
Cooling System ◽  
Engine Performance ◽  
Test Methods ◽  
Standard Test ◽  
Radial Deformation ◽  
Seal Design ◽  
Vulcanized Rubber ◽  
Before And After

In the past ten years diesel engine performance has significantly increased in terms of kilowatts/litre (kW/L). These higher power density outputs create higher thermal loads on the cooling system and associated seals. While compatibility of elastomers in high temperature coolants has been studied and reported, the inevitable impact of thermal cycling on these elastomers is not well documented. This study examines the effects of thermal cycling in three general coolant categories on three different elastomers commonly considered for sealing hot engine coolants. The elastomers, by ASTM D1418 designation, are HNBR, FKM Type 2, and FEPM. The coolants are an organic acid technology (OAT) coolant, a propylene glycol premix coolant, and a corrosion inhibited de-ionized water. Normal service applications are characterized by an indefinite number of shutdowns and startups. Testing was designed to simulate such service. Aging periods incorporated ongoing 24 hour cycles: a 16 hour period to heat up and operate at 150°C, and an 8 hour period to cool off to ambient. O-rings, a common seal design, were subject to axial and radial deformation during testing. The o-rings’ sealing attributes were examined after four, ten, twenty, and forty cycles. Elastomeric properties were evaluated, before and after cyclical aging, in accordance with ASTM D1414-94 (“Standard Test Methods for Rubber O-rings”) and D412-06a (“Standard Test Methods for Vulcanized Rubber … - Tension”). Compressive stress relaxation (CSR) was evaluated using an in-house procedure, comporting with ASTM D6147-94.

Mastication of Rubber a Study of Some of the Oxidation Rocesses Involved

1939 ◽  
Vol 12 (2) ◽  
pp. 163-175 ◽  
Author(s):  
W. F. Busse ◽  
E. N. Cunningham
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Thermal Oxidation ◽  
Oxygen Concentration ◽  
High Temperatures ◽  
Nitroso Compounds ◽  
Temperature Reaction ◽  
Vulcanized Rubber ◽  
High Temperature Reaction ◽  
Internal Mixer

Abstract The rate of breakdown of smoked sheet, pale crepe, and sprayed-latex rubber in a laboratory internal mixer is a minimum at temperatures around 240° F., and the rate may be increased as much as four- or five-fold by either raising or lowering the temperature 80° F. The high-temperature reaction (above 240° F.) probably is similar to the thermal oxidation which occurs when rubber is heated in air, since the rates of both reactions are increased by increasing the oxygen concentration, and they are reduced by adding antioxidants. The low-temperature reaction (below 240° F.) may involve a mechanical acti-vation of the rubber, as in milling. The rate of this reaction first increases and then remains constant or decreases slightly as the oxygen concentration in the temperature during mastication is increased from about 0.5% to 20% to 100%. Some nitroso compounds are powerful stiffeners of rubber, and they change the softness-retentivity relation, making it more like that of reclaim or semi-vulcanized rubber. The effect of most commonly used “softeners” on the plasticity of rubber is small compared with the effect of changing the mastication temperature ±40° F. Exceptions to this are certain vulcanization accelerators (at high temperatures), hydrazine compounds and thiophenols, which appear to be true mastication acelerators or oxidation catalysts.

Oxidative and Nonoxidative Thermal Degradation of Rubber

1956 ◽  
Vol 29 (3) ◽  
pp. 857-879 ◽  
Author(s):  
G. J. van Amerongen
Keyword(s):  
Mechanical Properties ◽  
Thermal Decomposition ◽  
High Temperature ◽  
Thermal Degradation ◽  
High Resistance ◽  
Marked Change ◽  
Vulcanized Rubber ◽  
Resistance To Oxidation ◽  
Thermal Deterioration ◽  
Short Time

Abstract The mechanical properties of rubber often undergo a marked change on heating, with deterioration of its elasticity and strength as a result. This behavior is a problem not merely where rubber is used in surroundings of prevailing high temperature; arguments can be advanced to show that thermal deterioration may influence to some extent as seemingly remote a property as wear. The behavior of rubber exposed to heat is strongly influenced by the presence or absence of oxygen. When an ordinary rubber vulcanizate is heated to, say, 100° C in the presence of oxygen or air, it undergoes substantial changes in a comparatively short time. Yet the effects may be similar in the absence of oxygen at temperatures 60° to 100° C higher. The inference is that, although a given rubber heated in air to 100° C, for instance, may be stable owing to its high resistance to oxidation, it may become completely unstable when heated to 180° C on account of thermal decomposition. This paper is published to provide fuller details of the behavior of rubber when heated in the presence and absence of oxygen. The evidence was obtained from experiments with both unvulcanized and vulcanized rubber, differing in composition.

Influence of Thermo-Mechanical Processing on the Microstructure of Beryllia Dispersed Nickel Alloys

1973 ◽  
Vol 31 ◽  
pp. 184-185
Author(s):  
M.S. Grewal ◽  
S.A. Sastri ◽  
N.J. Grant
Keyword(s):  
High Temperature ◽  
Nickel Alloys ◽  
Thermomechanical Processing ◽  
Cold Work ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Mechanical Processing ◽  
Uniform Dispersion ◽  
Oxide Particles ◽  
Nickel Base

Currently there is a great interest in developing nickel base alloys with fine and uniform dispersion of stable oxide particles, for high temperature applications. It is well known that the high temperature strength and stability of an oxide dispersed alloy can be greatly improved by appropriate thermomechanical processing, but the mechanism of this strengthening effect is not well understood. This investigation was undertaken to study the dislocation substructures formed in beryllia dispersed nickel alloys as a function of cold work both with and without intermediate anneals. Two alloys, one Ni-lv/oBeo and other Ni-4.5Mo-30Co-2v/oBeo were investigated. The influence of the substructures produced by Thermo-Mechanical Processing (TMP) on the high temperature creep properties of these alloys was also evaluated.

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

Effect of Improved ThO2 Particle Dispersion in Nickel on High-Temperature Strength

1970 ◽  
Vol 28 ◽  
pp. 444-445
Author(s):  
E. R. Kimmel ◽  
H. L. Anthony ◽  
W. Scheithauer
Keyword(s):  
High Temperature ◽  
Metal Matrix ◽  
Oxide Particle ◽  
Oxide Phase ◽  
Dislocation Motion ◽  
Particle Dispersion ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Oxide Particles ◽  
The Stability

The strengthening effect at high temperature produced by a dispersed oxide phase in a metal matrix is seemingly dependent on at least two major contributors: oxide particle size and spatial distribution, and stability of the worked microstructure. These two are strongly interrelated. The stability of the microstructure is produced by polygonization of the worked structure forming low angle cell boundaries which become anchored by the dispersed oxide particles. The effect of the particles on strength is therefore twofold, in that they stabilize the worked microstructure and also hinder dislocation motion during loading.

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