Effect of Antioxidants in Typical Rubber Stocks

1929 ◽  
Vol 2 (3) ◽  
pp. 456-461
Author(s):  
Marion C. Reed
Keyword(s):  
Inert Gas ◽  
Truck Tire ◽  
Rubber Compounds ◽  
Heavy Truck ◽  
Resistance To Heat

Abstract The results of these tests show that antioxidants are of value in stocks which become hot in service, such as bus tubes, belt frictions, and heavy truck tire treads. It is believed that aging at 90° C., both in air and in an inert gas free from oxygen, will be of assistance in separating the factors of oxidation and overcure in designing rubber compounds for resistance to heat.

Natural Rubber Compounds for Truck Tires

1985 ◽  
Vol 58 (4) ◽  
pp. 740-750 ◽  
Author(s):  
D. Barnard ◽  
C. S. L. Baker ◽  
I. R. Wallace
Keyword(s):  
Stearic Acid ◽  
Heat Generation ◽  
Rolling Resistance ◽  
Synthetic Compound ◽  
Wear Performance ◽  
Test Pieces ◽  
Truck Tire ◽  
Truck Tires ◽  
Rubber Compounds ◽  
Lower Severity

Abstract An 80 NR/20 BR truck tread compound containing a semi-EV cure system and modified with a 6.0 phr level of stearic acid has been shown to exhibit excellent resistance to reversion when compared to a similar compound containing a normal 2.0 phr level of stearic acid. Improvements in the retention of laboratory abrasion resistance, heat generation, and most physical properties have been identified on test pieces subjected to typical truck retread overcure conditions. In highway fleet testing trials of 1100 × 22.5 truck retreads fitted to both third and fourth drive axles of tipper trucks, the modified compound displayed a 42% improvement in treadwear performance over the normal compound in the lower severity third axle positions while performance in the higher severity fourth axle positions was inferior by 20%. In comparison to a 55 SBR/45 BR truck tread, both NR compounds displayed superior wear performance on the fourth axles while some further adjustments of the modified compound are required to match the synthetic compound on the third axles. The reversal of wear performances for all compounds between third and fourth axles is due to the different abrasion mechanisms encountered. Laboratory abrasion rankings do not correlate with wear performances of compounds on the fourth drive axle of trucks, but they do correlate with wear performances on third drive axles. Despite the reversion characteristics of the normal semi-EV compound, no significant adverse effect on treadwear performance was evident at the start of tire life. The low heat generation of the modified compound in laboratory tests is confirmed in actual tire testing. Advantages in rolling resistance characteristics are also evident for the modified compound. Current studies at MRPRA suggest that further modifications of cure system design, in combination with the optimization of NR/BR ratios and mixing methods, will potentially provide NR dominant truck tread compounds which will exhibit superior wear performance in both the higher and lower abrasion severities encountered in heavy-duty truck tire service conditions.

Carboxylic Rubbers. I. Synthesis and Structures

1959 ◽  
Vol 32 (1) ◽  
pp. 321-327 ◽  
Author(s):  
B. A. Dolgoplosk ◽  
E. I. Tinyakova ◽  
V. N. Reĭkh ◽  
T. G. Zhuravleva ◽  
G. P. Belonovskaya
Keyword(s):  
Polymer Chain ◽  
High Strength ◽  
Chemical Compounds ◽  
Good Resistance ◽  
Synthetic Rubber ◽  
Rubber Compounds ◽  
Work Done ◽  
Styrene Butadiene ◽  
Resistance To Heat ◽  
Butadiene Styrene

Abstract It is well known that the high strength of unfilled (pure gum) natural rubber and some synthetic rubber compounds can be explained by the homogeneity of the polymer chain which determines its ability to crystallize or to orient on stretching. The character of the vulcanization network as well as the structure of the main chain is of importance. This has been verified by the use of polyethylene polyamines and other chemical compounds as vulcanization accelerators for butadiene-styrene rubber (SKS-30A) to produce high strength (up to 200 kg/cm2) gum rubber compounds. In certain cases, only the structure of the vulcanization network obtained with carboxyl-containing rubber compounds can account for obtaining the same effects as are obtained with natural or other synthetic rubber compounds as a result of homogeneity of polymer chain. The first work done by us on carboxyl-containing (carboxylic) rubbers was done in 1954\2-1955. In this work it was shown that polymers of isoprene and of butadiene, copolymers of butadiene with styrene, butadiene with acrylonitrile, and others, which contain small quantities of methacrylic acid (1\2-2 mole %) in the chain, can be vulcanized with oxides of divalent metals to give pure gum and lightly filled compounds characterized by high strength and elasticity, good resistance to heat aging and good cut growth resistance.

Processing Characteristics of Rubber Compounds- - -. Effect of Pigment Particle Size and Surface

1938 ◽  
Vol 11 (3) ◽  
pp. 585-590
Author(s):  
A. H. Nellen ◽  
C. E. Barnett
Keyword(s):  
Particle Size ◽  
Tensile Strength ◽  
Zinc Oxide ◽  
Abrasion Resistance ◽  
Pigment Particle ◽  
Rubber Compound ◽  
Zinc Oxides ◽  
Truck Tire ◽  
Rubber Compounds ◽  
Processing Properties

Abstract A STUDY of the processing properties imparted by any pigment to a rubber compound is important in determining the most effective and economical type of pigment for a particular purpose. For example, in a truck tire carcass compound where zinc oxide may be the main pigment, in order to obtain the maximum quality this zinc oxide should be of the type which will give a soft uncured stock and free-flowing qualities so that the cords in the carcass may be thoroughly impregnated during the calendering and curing processes. Also, in a tread compound where channel black is the main pigment, that type of black which will allow faster incorporation into the rubber, faster extrusion, and better flowing qualities will result in manufacturing economies. In the case of both the zinc oxides and the carbon blacks it is essential that these desirable processing characteristics be obtained without losses in other properties, such as rate of cure, tensile strength, and abrasion resistance.

Viscoelastic Properties of Truck Tire Compounds and the Related Heat Build-Up

1972 ◽  
Vol 45 (1) ◽  
pp. 1-9
Author(s):  
P. Kainradl ◽  
G. Kaufmann
Keyword(s):  
Multiple Regression ◽  
Viscoelastic Properties ◽  
Loss Factor ◽  
Truck Tire ◽  
Rubber Compounds ◽  
Minimum Residual ◽  
Shoulder Region ◽  
Rubber Coating ◽  
Heat Build Up ◽  
Operating Temperatures

Abstract Rubber compounds used in the manufacture of tread-cap, tread-base, and for the rubber-coating of the rayon cord for 12.00–20 tires have been varied in composition and, in consequence, their viscoelastic properties have been altered. Operating temperatures, in test-wheel runs, have been measured in the shoulder region of the tire close to the casing, using a needle-thermocouple. Multiple-regression has been used to investigate which combinations of viscoelastic properties of the rubber vulcanizates would give a linear, significant correlation to the heat build-up in the tire with a minimum residual. From the nature of the variables in the regression functions, conclusions have been drawn on the type of load occurring in the different components of the tire. It was found that the tread cap contributed to the heat build-up according to its loss compliance E″/|E*|2 and the carcass according to its loss-factor, E″/E′. Thus, the statistics show that the greater contribution to the heat build-up comes from the tread-base, according to its loss-factor also. The values of temperatures, calculated by the multiple-regression, show deviations of only a few degrees centigrade compared to the average temperatures of tires of the same construction. Therefore the operating temperatures of tires to be expected as a result of the compound variations can be estimated in advance. On individual tires greater deviations, up to 10°C, have been measured. These are due to inevitable inaccuracies in tire building and errors in temperature measurements.

Carboxylic Rubbers. II. Properties of Cured Stocks

1959 ◽  
Vol 32 (1) ◽  
pp. 328-336 ◽  
Author(s):  
B. A. Dolgoplosk ◽  
V. N. Reĭkh ◽  
E. I. Tinyakova ◽  
A. E. Kalaus ◽  
Z. A. Koryushenko ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Elastic Properties ◽  
Good Resistance ◽  
Synthetic Rubber ◽  
Rubber Compounds ◽  
Resistance To Heat

Abstract The experimental evidence shows that the mechanical and elastic properties of the carboxylic rubber compounds far exceed those of the synthetic rubber type compounds. Important qualities of gum and lightly filled carboxylic rubber compounds are: good mechanical and elastic properties, high cut growth resistance and good resistance to heat aging. The disadvantage is the tendency of the carboxylic rubber mixtures to scorch. Carboxylic rubbers are of considerable interest for the preparation of general and special purpose rubber compounds.

A Test to Evaluate Fatigue Crack Growth in Rubber Compounds under Mixed Mode Loading

2001 ◽  
Vol 29 (1) ◽  
pp. 44-55 ◽  
Author(s):  
G. P. Giuliani ◽  
G. Medri ◽  
A. Pirondi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Mixed Mode ◽  
Field Tests ◽  
Crack Growth Resistance ◽  
Mixed Mode Loading ◽  
Fatigue Crack Growth Resistance ◽  
Truck Tire ◽  
Rubber Compounds

Abstract An experimental method to evaluate the crack growth rate in rubber compounds under mixed mode loading is presented. This method for measuring fatigue crack growth resistance of compounds for truck tire applications yields results that are comparable in ranking to field tests.

scholarly journals Characterizing the Intrinsic Strength (Fatigue Threshold) of Natural Rubber/Butadiene Rubber Blends

2019 ◽  
Vol 47 (4) ◽  
pp. 292-307 ◽  
Author(s):  
Christopher G. Robertson ◽  
Radek Stoček ◽  
Christian Kipscholl ◽  
William V. Mars
Keyword(s):  
Energy Dissipation ◽  
Natural Rubber ◽  
Endurance Limit ◽  
Fatigue Threshold ◽  
Butadiene Rubber ◽  
Rubber Blends ◽  
Truck Tire ◽  
Rubber Compounds ◽  
Proper Account ◽  
Intrinsic Strength

ABSTRACT Tires require rubber compounds capable of enduring more than 108 deformation cycles without developing cracks. One strategy for evaluating candidate compounds is to measure the intrinsic strength, which is also known as the fatigue threshold or endurance limit. The intrinsic strength is the residual strength remaining in the material after the strength-enhancing effects of energy dissipation in crack tip fields are removed. If loads stay always below the intrinsic strength (taking proper account of the possibility that the intrinsic strength may degrade with aging), then cracks cannot grow. Using the cutting protocol proposed originally by Lake and Yeoh, as implemented on a commercial intrinsic strength analyzer, the intrinsic strength is determined for a series of carbon black (CB) reinforced blends of natural rubber (NR) and butadiene rubber (BR) typical of tire applications. The intrinsic strength benefits of the blends over the neat NR and BR compounds are only observed after aging at temperatures in the range from 50 to 70 °C, thus providing fresh insights into the widespread durability success of CB-filled NR/BR blends in tire sidewall compounds and commercial truck tire treads.

Acoustic levels of heavy truck tire ruptures

2013 ◽  
Vol 20 (4) ◽  
pp. 264-269 ◽  
Author(s):  
Matthew Wood ◽  
William Woodruff
Keyword(s):  
Truck Tire ◽  
Heavy Truck

Basic Studies of Extrusion of Rubber Compounds in a Pin Barrel Extruder

1993 ◽  
Vol 66 (1) ◽  
pp. 121-138 ◽  
Author(s):  
Kyung-Chul Shin ◽  
James L. White
Keyword(s):  
Experimental Study ◽  
Carbon Black ◽  
Compound A ◽  
Truck Tire ◽  
Rubber Compounds ◽  
Mixing Characteristics ◽  
Basic Studies

Abstract An experimental study of the flow, pumping, and mixing characteristics of three different rubber-carbon black compounds in a model pin barrel extruder is presented. These are a model SBR/BR passenger tire compound, a NR truck tire compound, and a NBR mechanical goods compound. Comparisons are made of the initial extruder without pins or slices/grooves in the screw flights, an extruder containing slices or grooves in its flights, and a pin barrel extruder. It is found for each compound that introducing slices in screw flights improves mixing/homogenization and decreases pumping ability. Introduction of pins improves mixing/homogenization and has little effect on pumping. The homogenization is best for the passenger tire tread compound and worst for the NBR mechanical good compound.

Fission Gas Bubbles in Fractured UO2

1968 ◽  
Vol 26 ◽  
pp. 286-287
Author(s):  
O. M. Katz
Keyword(s):  
Electron Microscopy ◽  
Thermal Gradient ◽  
Gas Bubbles ◽  
Inert Gas ◽  
Thermal Gradients ◽  
Fission Gas ◽  
Beam Heating ◽  
Limited Application ◽  
Bubble Characteristics ◽  
Electron Beam Heating

The swelling of irradiated UO2 has been attributed to the migration and agglomeration of fission gas bubbles in a thermal gradient. High temperatures and thermal gradients obtained by electron beam heating simulate reactor behavior and lead to the postulation of swelling mechanisms. Although electron microscopy studies have been reported on UO2, two experimental procedures have limited application of the results: irradiation was achieved either with a stream of inert gas ions without fission or at depletions less than 2 x 1020 fissions/cm3 (∼3/4 at % burnup). This study was not limited either of these conditions and reports on the bubble characteristics observed by transmission and fractographic electron microscopy in high density (96% theoretical) UO2 irradiated between 3.5 and 31.3 x 1020 fissions/cm3 at temperatures below l600°F. Preliminary results from replicas of the as-polished and etched surfaces of these samples were published.

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