Scorching, and Other Plasticity Changes in Rubber Compounds on Heating

1931 ◽  
Vol 4 (4) ◽  
pp. 552-559
Author(s):  
E. O. Dieterich ◽  
J. M. Davies
Keyword(s):  
Temperature Effects ◽  
Room Temperature ◽  
Degree Of Cure ◽  
Test Pieces ◽  
Rubber Compounds ◽  
Operating Temperatures ◽  
Safe Operating

Abstract A method is described which employs the Goodrich plastometer for detecting the initial stages of vulcanization of uncured rubber compounds. Reduction in plasticity, at standard room temperature, of test pieces previously heated for various intervals at selected temperatures is used to determine the degree of cure and thus to estimate safe operating temperatures and periods. Examples of the application of the method to a variety of compounds are presented. Other temperature effects, such as heat stiffening and softening, which have not previously been reported, are illustrated.

Thiuram Disulfides in Compounding

1947 ◽  
Vol 20 (3) ◽  
pp. 803-807
Author(s):  
G. D. Morrison ◽  
T. Shepherd
Keyword(s):  
Zinc Oxide ◽  
Stearic Acid ◽  
Room Temperature ◽  
Milling Time ◽  
Steam Pressure ◽  
Base Stock ◽  
Large Batch ◽  
Percentage Recovery ◽  
Test Pieces ◽  
Rubber Compounds

Abstract Perhaps the chief drawback to the greater employment of thiuram disulfides has been the fear, often groundless, of scorching during processing, and for this reason the work detailed in this paper is devoted entirely to this aspect of their use. The scorching tendency, taken as the commencement of cure, and the rate of vulcanization were studied by means of a modified Goodrich type of plastometer, and the results are expressed as the percentage recovery against time in minutes at 120° C. This temperature (equivalent to 15 lbs. per sq. in. steam pressure) was chosen as being the highest likely to be reached in normal mixing, calendering and extrusion. The rubber compounds tested were prepared from one large batch of base stock comprising: smoked sheet rubber, 100 parts; zinc oxide, 5 parts; and stearic acid, 2 parts. After mixing, the stock was divided into the required number of portions and to these were added the various ingredients detailed later; in all cases the same milling time and temperatures were adhered to so that results would be comparable, especially plasticity. An interval of 24 hours at room temperature was allowed in each case before cutting plastometer test-pieces to dissipate strains imposed in the stock during mixing and sheeting. The test-pieces were then placed in an oven at 120° C, and percentage recovery determinations were made at 5-minute intervals over a range of 5 to 60 minutes.

Effect on Vulcanized Rubber Compounds of Immersion in Boiling Water

1931 ◽  
Vol 4 (3) ◽  
pp. 426-436
Author(s):  
K. J. Soule
Keyword(s):  
Water Absorption ◽  
Room Temperature ◽  
Anomalous Behavior ◽  
Boiling Water ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Actual Change

Abstract Further work is very desirable on the effect of different accelerators, antioxidants, and fluxes. It is possible that their study will throw more light on the mechanism of the swelling phenomena, and also help to explain the anomalous behavior of some of the fillers tested. It would also seem to be worth while to study the action of a few selected stocks in water, at several temperatures between room temperature and 100° C., to determine if the water absorption and swelling merely increase with rising temperatures, or whether there might be an actual change in behavior at different temperatures.

scholarly journals Temperature Effects on Optical Trapping Stability

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 954
Author(s):  
Dasheng Lu ◽  
Francisco Gámez ◽  
Patricia Haro-González
Keyword(s):  
Brownian Motion ◽  
Environmental Conditions ◽  
Temperature Effects ◽  
Room Temperature ◽  
Optical Trapping ◽  
State Of The Art ◽  
Thermal Sensing ◽  
The Stability ◽  
Object Of Study ◽  
Optically Trapped

In recent years, optically trapped luminescent particles have emerged as a reliable probe for contactless thermal sensing because of the dependence of their luminescence on environmental conditions. Although the temperature effect in the optical trapping stability has not always been the object of study, the optical trapping of micro/nanoparticles above room temperature is hindered by disturbances caused by temperature increments of even a few degrees in the Brownian motion that may lead to the release of the particle from the trap. In this report, we summarize recent experimental results on thermal sensing experiments in which micro/nanoparticles are used as probes with the aim of providing the contemporary state of the art about temperature effects in the stability of potential trapping processes.

scholarly journals Room Temperature vs Ice Cold - Temperature Effects on Cardiac Cell Action Potential

2016 ◽  
Vol 110 (3) ◽  
pp. 587a ◽  
Author(s):  
Ken Wang ◽  
Andreu Climent ◽  
David Gavaghan ◽  
Peter Kohl ◽  
Christian Bollensdorff
Keyword(s):  
Action Potential ◽  
Temperature Effects ◽  
Room Temperature ◽  
Cold Temperature ◽  
Cardiac Cell

Measurement of the Aging of Rubber Vulcanizates

1960 ◽  
Vol 33 (2) ◽  
pp. 502-509 ◽  
Author(s):  
J. Mandel ◽  
F. L. Roth ◽  
M. N. Steel ◽  
R. D. Stiehler
Keyword(s):  
Aging Process ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Arrhenius Equation ◽  
Effective Means ◽  
Ultimate Elongation ◽  
Rubber Compounds ◽  
The Relationship

Abstract Ultimate elongation (strain at failure) can be used to assess the aging of all rubber vulcanizates. For this purpose, it appears that Equation (2) can be used to express the early part of the aging process, corresponding to a period of aging at room temperature of 10 or more years. Prediction of shelf aging from tests at two or more elevated temperatures is only possible if the relationship between aging and temperature is known. For some rubber compounds the Arrhenius equation appears to hold. In these instances, it provides an effective means for estimating shelf aging.

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.

The Compression Set Behavior of Nitrile Rubber

1973 ◽  
Vol 46 (1) ◽  
pp. 305-330 ◽  
Author(s):  
H-J. Jahn ◽  
H-H. Bertram
Keyword(s):  
Test Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Nitrile Rubber ◽  
Compression Set ◽  
Test Pieces ◽  
Steep Part ◽  
Cure Time ◽  
Different Temperatures ◽  
Lower Test

Abstract The compression set (C.S.) of a vulcanizate depends on the formulation, processing, and conditions of cure. The following factors are the most important: (a) the type of elastomer, (b) the curing system, (c) the type and amount of filler, (d) the type and amount of plasticizer, (e) the type and amount of antioxidant, (f) the type of cure (press, steam, or hot air), and (g) the cure time and temperature. The present paper is intended, as far as possible, to describe these relationships quantitatively. Most tests will refer to nitrile rubber. We have modified the C.S. method described in ASTM D-395. The deviations are as follows : (1) When C.S. is plotted as a function of the duration of compression, the resulting curves rise steeply for roughly the first seven days, afterwards becoming flatter. The higher the test temperature, the steeper the curve. The ordinary compression times of 22 and 70 h still correspond to the steep part of the C.S. curve; here relatively small inaccuracies in the compression time and test temperature bring large errors in the C.S. readings. Therefore, to improve the correlation between C.S. readings and field behavior the test was extended to seven days in most cases. Longer test times would have been experimentally impractical. (2) As a rule, only C.S. figures relating to 20°, 70°, and 100° C are found in the literature, so test temperatures were extended to include practical conditions. Generally, therefore, C.S. readings were taken at twelve different temperatures ranging from −60° C to +160° C. (3) According to the standards the test pieces should be cooled to room temperature after removal of the load and before the recovery measurement is carried out. Only ASTM D-1229-62 requires the remeasurement to be taken at the load temperature. This ensures accurate measurements of the C.S. at low temperatures. In our tests this was done in every case because at high temperature the C.S. readings are lower since (1) many elastomers recover better at elevated temperatures than at room temperature and (2) the thermal expansion of the test piece can be measured in addition to the recovery. Nevertheless, the differences between remeasurements taken at room temperature and the test temperature are small if the test temperature is fairly high. Where lower test temperatures are used, the remeasurement should always be taken at test temperature if useful results are to be obtained. In all the tests the time allowed for recovery between removal of the load and the remeasurement was thirty min.

Cryogenic to room temperature effects of NBTI in high-k PMOS devices

2011 ◽  
Author(s):  
Richard G. Southwick ◽  
Shem T. Purnell ◽  
Blake A. Rapp ◽  
Ryan J. Thompson ◽  
Shane K. Pugmire ◽  
...  
Keyword(s):  
Temperature Effects ◽  
Room Temperature ◽  
High K

Safe Operating Temperatures for Pressurized Alkaline Hydrolysis of HMX-Based Explosives

2000 ◽  
Vol 39 (5) ◽  
pp. 1215-1220 ◽  
Author(s):  
Robert L. Bishop ◽  
David M. Harradine ◽  
Raymond L. Flesner ◽  
Sheldon A. Larson ◽  
David A. Bell
Keyword(s):  
Alkaline Hydrolysis ◽  
Operating Temperatures ◽  
Hydrolysis Of ◽  
Safe Operating
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