Tensile Properties of Natural and Synthetic Rubbers at Elevated and Subnormal Temperatures

1950 ◽  
Vol 23 (2) ◽  
pp. 338-346 ◽  
Author(s):  
B. S. T. T. Boonstra
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Carbon Black ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
High Temperature Strength ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Abstract It is necessary to determine the physical properties of rubbers at relatively high temperatures when products made from them are to be used at such temperatures in actual service. The term heat aging is used when the vulcanizate is tested at room temperature, exposed to elevated temperatures for given periods of time, and then tested again at room temperature. The term high-temperature strength is proposed for values obtained when the vulcanizates are tested at the actual higher service temperatures. Effective comparison of natural and synthetic rubbers is best obtained by determining tensile product values, which are the result of the combining of tensile strength and elongation values. In the evaluating of vulcanizates of tire compounds of various rubbers, another factor must be taken into account. Synthetic-rubber tires develop more heat in service than do natural-rubber tires, and the former therefore generally operate at higher temperatures than do the latter. Synthetic-rubber tires therefore require a greater high temperature strength than do natural rubber tires, but, as has been shown, synthetic rubbers actually have a lower high-temperature strength. The part played by carbon black with respect to the tensile properties of some synthetic rubbers is considered that of a substitute for crystallization in natural and other synthetic rubbers, which substitute does not, however, possess the same favorable features. Carbon black even in noncrystallizing rubbers does not increase strength; it merely shifts the optimum strength value to a higher temperature so that this temperature is in the room temperature range. The temperature coefficient of strength for Butyl and Neoprene rubbers is so large at room temperature that a few degrees' difference in temperature causes large changes in strength. The tensile strength and elongation at break of these two rubbers decrease sharply between 20 and 40° C.

Role of Ti/Al Ratio of Ti-Al-X (X=Cr, Nb, Ta and W) Intermetallics on High Temperature Tensile Properties

2014 ◽  
Vol 783-786 ◽  
pp. 1136-1141
Author(s):  
Keizo Hashimoto
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Tensile Properties ◽  
First Generation ◽  
Elevated Temperatures ◽  
Atomic Ratio ◽  
High Temperature Strength ◽  
The Third ◽  
High Temperature Tensile ◽  
High Temperature Tensile Properties

The mechanical properties of g-TiAl at elevated temperatures have been investigated extensively over the last 30 years. Designed alloys have been proposed from the first generation alloy (Ti-48Al-2Cr-2Nb) to the second, the third and the fourth generations. However, a decisive chemical composition of g-TiAl has not been agreed among researchers yet. The main reasons for this situation are difficulties in compositional control of Ti-Al-X-Y. In this paper, the high temperature tensile properties of g-TiAl alloy with lots of different composition have been examined from the room temperature to 1200C and the tensile strength data of those specimens have been summarized. It is clear that Ti/Al atomic ratio plays an important role on the behaviors of the high temperature strength since the Ti/Al atomic ratio is strongly related to the phase stabilities between g and a2phases in the binary Ti-Al phase diagram. A very narrow confine of a/a2atomic ratio exists in the specimens having the comparatively high tensile strength at the elevated temperatures. Moreover, additions of the third elements such as Cr, Nb, Ta and W to g-TiAl contribute on the increase of the tensile strength and the shift of the phase stability among a2, b and g phases. In order to utilize g-TiAl alloys in the various machine components at high temperatures, the severe process controls of melting, casting, thermo-mechanical treatments and heat treatments are indispensable.

Effect of High Temperature Caliber Rolling on Microstructure and Room Temperature Tensile Properties of Mg-3Al-1Zn (AZ31) Alloy

2013 ◽  
Vol 209 ◽  
pp. 6-9 ◽  
Author(s):  
Rajendra Doiphode ◽  
S.V.S. Narayana Murty ◽  
Nityanand Prabhu ◽  
Bhagwati Prasad Kashyap
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Yield Strength ◽  
Strain Rate ◽  
Tensile Properties ◽  
Room Temperature ◽  
Tensile Tests ◽  
Az31 Alloy ◽  
Rolling Temperature ◽  
Grain Sizes

Mg-3Al-1Zn (AZ31) alloy was caliber rolled at 250, 300, 350, 400 and 450 °C. The effects of caliber rolling temperature on the microstructure and tensile properties were investigated. The room temperature tensile tests were carried out to failure at a strain rate of 1 x 10-4s-1. The nature of stress-strain curves obtained was found to vary with the temperature employed in caliber rolling. The yield strength and tensile strength followed a sinusoidal behaviour with increasing caliber rolling temperature but no such trend was noted in ductility. These variations in tensile properties were explained by the varying grain sizes obtained as a function of caliber rolling temperature.

Increased High Temperature Oxidation Resistance of Ni20Cr20Fe5Nb1Y2O3 Alloy with Nano-Sized Grains

2005 ◽  
Vol 486-487 ◽  
pp. 109-112 ◽  
Author(s):  
Il Ho Kim ◽  
S.I. Kwun
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Mechanical Alloying ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Tensile Property ◽  
High Temperature Oxidation ◽  
Room Temperature ◽  
Dispersion Strengthening ◽  
Temperature Oxidation

The oxidation and tensile properties of a Ni20Cr20Fe5Nb alloy and a Ni20Cr20Fe 5Nb1Y2O3 alloy with nano-sized grains were compared with those of the comercial IN718 alloy. The oxidation resistance of the Ni20Cr20Fe5Nb1Y2O3 alloy was superior to that of the Ni20Cr20Fe5Nb and IN 718 alloys. This superior oxidation resistance was the result of both the formation of dense oxides on the surface of the alloy and the interruption of Cr migration in the alloy by the addition of Y2O3. Moreover, the tensile property of the Ni20Cr20Fe5Nb1Y2O3 alloy at room temperature and 400oC was higher than that of the Ni20Cr20Fe5Nb and IN718 alloys by more than 300MPa (30%). This result can be attributed to the dispersion strengthening of Y2O3. The relatively low tensile strength at 600°C and 800°C of the alloys fabricated by mechanical alloying was attributed to grain refinement showing intergranular fracture at high temperatures.

High-Temperature Compression Testing of Graphite

1953 ◽  
Vol 20 (2) ◽  
pp. 289-294
Author(s):  
Leon Green
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
High Temperature ◽  
Stress Relaxation ◽  
Temperature Control ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Limited Degree ◽  
Relaxation Curves ◽  
Short Time

Abstract Experiments on the compression of graphite cylinders at elevated temperatures are described. It is found that the short-time compressive strength increases with temperature in the range from room temperature to 2000 C, a variation which is consistent with the previously reported behavior of the tensile strength. Photographs of typical modes of deformation and their corresponding stress-strain curves are presented, but a limited degree of temperature control renders the curves semiquantitative in nature. The large, mutually opposing influences of temperature and strain rate are illustrated by photographs of typical failures, and stress-relaxation curves manifest the plasticity of graphite at high temperatures.

CIS-1,4 Polyisoprene Prepared with Alkyl Aluminum and Titanium Tetrachloride

1958 ◽  
Vol 31 (4) ◽  
pp. 838-846 ◽  
Author(s):  
H. E. Adams ◽  
R. S. Stearns ◽  
W. A. Smith ◽  
J. L. Binder
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Room Temperature ◽  
Titanium Tetrachloride ◽  
Polymerization Temperature ◽  
Solution Polymerization ◽  
Lower Temperature ◽  
Hysteretic Properties

Abstract By adjustment of the relative amounts of the two components of the catalyst and the temperature of polymerization, cis-1,4 polyisoprene can be produced free from trans-1,4 configuration. Catalysts containing a mole ratio of alkyl aluminum to titanium tetrachloride of 1.0 produce polymers with this configuration at room temperature. At lower temperature of polymerization, somewhat higher ratios are needed to achieve the same result. Solution polymerization was used to control the reaction and obtain a uniform product. It was necessary to use 3 to 5 phm of total catalyst to obtain 100 per cent yield in 4 hours at room temperature. The inherent viscosity of the polymers made under these conditions is low, usually 2.0 to 2.5. However, higher molecular weight polymers are produced at lower polymerization temperature. Compounding studies indicate that vulcanizates of these polymers possess both normal and hot tensile properties comparable to natural rubber. Hysteretic properties of the carbon black vulcanizates of the polymers studied are inferior to those of natural rubber.

STUDIES OF POLYMERS AND OF POLYMERIZATION.: VI. THE VULCANIZATION OF METHYL RUBBER

1932 ◽  
Vol 6 (4) ◽  
pp. 398-408 ◽  
Author(s):  
George Stafford Whitby ◽  
Morris Katz
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Temperature Increase ◽  
Room Temperature ◽  
Breaking Strength ◽  
Synthetic Rubber ◽  
Room Temperature Increase

Samples of synthetic rubber prepared by the polymerization of dimethylbutadiene at room temperature and at 45 °C. respectively were subjected to vulcanization tests in comparison with natural rubber. In an accelerated gum stock containing 3% sulphur the cold polymer gave at best vulcanized products less than one-third as strong and only about one-third as extensible as natural rubber; the heat polymer gave products as extensible but only one-tenth as strong as natural rubber. The incorporation of carbon black greatly increased the strength of the synthetic rubbers, rendering both about half as strong as natural rubber in a similar stock. The vulcanized synthetic rubbers were less "snappy" than natural rubber at room temperature. Increase of temperature improved their speed of retraction, but seriously reduced their breaking strength. Products from the cold polymer showed a greatly increased stiffness and strength at 5 °C. as compared with room temperature, and at about 1 °C. were non-retractible. In general the synthetic rubbers were much more sensitive than natural rubber to change of temperature. A 50:50 mixture of the heat and cold polymers was also subjected to tests.

S.A.P.-865

Alloy Digest ◽  
1965 ◽  
Vol 14 (8) ◽  
Keyword(s):  
Tensile Strength ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Engineering Properties ◽  
Powder Metal ◽  
High Tensile Strength ◽  
Temperature Performance ◽  
Sintered Aluminum

Abstract SAP is a special Sintered Aluminum Powder characterized by high tensile strength at room temperature and at elevated temperatures. It features a range of useful engineering properties. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, machining, joining, and powder metal forms. Filing Code: Al-146. Producer or source: Aluminium Industrie Atkiengesellschaft.

Studies of Polymers and of Polymerization. VI. The Vulcanization of Methyl Rubber

1932 ◽  
Vol 5 (4) ◽  
pp. 566-575
Author(s):  
George Stafford Whitby ◽  
Morris Katz
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Temperature Increase ◽  
Room Temperature ◽  
Breaking Strength ◽  
Synthetic Rubber ◽  
Room Temperature Increase

Abstract Samples of synthetic rubber prepared by the polymerization of dimethylbutadiene at room temperature and at 45° C., respectively, were subjected to vulcanization tests in comparison with natural rubber. In an accelerated gum stock containing 3% sulfur the cold polymer gave at best vulcanized products less than one-third as strong and only about one-third as extensible as natural rubber; the heat polymer gave products as extensible but only one-tenth as strong as natural rubber. The incorporation of carbon black greatly increased the strength of the synthetic rubbers, rendering both about one-half as strong as natural rubber in a similar stock. The vulcanized synthetic rubbers were less “snappy” than natural rubber at room temperature. Increase of temperature improved their speed of retraction, but seriously reduced their breaking strength. Products from the cold polymer showed a greatly increased stiffness and strength at 5° C. as compared with room temperature, and at about 1° C. were non-retractible. In general the synthetic rubbers were much more sensitive than natural rubber to change of temperature. A 50:50 mixture of the heat and cold polymers was also subjected to tests.

Mixing Process of Natural and Synthetic Polyisoprene Rubbers

1981 ◽  
Vol 54 (2) ◽  
pp. 211-226 ◽  
Author(s):  
M. A. Ponce ◽  
R. R. Ramirez
Keyword(s):  
Tensile Strength ◽  
Energy Consumption ◽  
Carbon Black ◽  
Tensile Properties ◽  
Mixing Times ◽  
Mixing Process ◽  
Low Resolution ◽  
Degree Of Dispersion ◽  
Different Temperatures ◽  
Natural And Synthetic

Abstract The mixing process, in a Brabender Plasticorder with a cam-type mixing head, was studied with NR (natural Hevea rubber), GR (natural guayule rubber) and IR (synthetic polyisoprene) at two different temperatures (60 and 80°C), with three types of carbon black (EPC, FEF and HAF), each one at three different concentrations (30, 50 and 70 phr). Samples for analysis were obtained at six different mixing times. Development of mixing and dispersion was evaluated through the black incorporation times (BIT), energy consumption, and tensile properties, which have been correlated to the degree of dispersion determined by low resolution microscopy. BIT, Optimum Mixing Times and the energy consumed to reach those points are lower for GR and IR than for NR. Compounds obtained at Optimum Mixing Times show that GR has a lower modulus, similar tensile strength and higher elongations.

Carbon Blacks in GR-S

1946 ◽  
Vol 19 (1) ◽  
pp. 100-122 ◽  
Author(s):  
D. Parkinson
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Natural Rubber ◽  
Carbon Blacks ◽  
Styrene Copolymer ◽  
Synthetic Rubber ◽  
First Approximation ◽  
Different Types ◽  
Almost All ◽  
Butadiene Styrene

Abstract The importance of different types of colloidal carbon as reinforcing agents for the butadiene-styrene copolymer, GR-S, has been stressed in recent papers. It has been shown that, to a first approximation, the effect of carbon blacks in this type of synthetic rubber is similar to that in natural rubber, but it has been shown also that the extremely low tensile strength and poor tearing properties of uncompounded vulcanized GR-S necessitates the addition of some form of carbon black to almost all types of compounds. The present paper considers the influence of carbon blacks in vulcanized GR-S compounds. Earlier papers have discussed the effect of carbon blacks in natural rubber.

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