The Behavior of Rubber at Low Temperatures

1939 ◽  
Vol 12 (2) ◽  
pp. 344-364 ◽  
Author(s):  
M. Sagajłło ◽  
J. BobiŃska ◽  
H. Saganowski
Keyword(s):  
Elastic Properties ◽  
Low Temperatures ◽  
Small Degree ◽  
Freezing Resistance ◽  
Shock Absorbers ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
The Difference ◽  
Winter Time ◽  
High Degree

Abstract (1) Raw rubber, smoked sheet as well as crepe, freezes to a high degree at low temperatures. The difference between the freezing at −10° and −60° C. is comparatively small at initial elongations of 300 and 400%. With smaller initial elongations there is a greater difference in degree of freezing at temperatures of − 10° and −60° C. A complete loss of the elastic properties of the rubber takes place at −70° C. (2) Previous heating of raw rubber, even at a temperature of 140° C, has no effect on its freezing-resistance. (3) The susceptibility of rubber to freezing increases with increase of the elongation, this effect being strongly marked above an elongation of 200%. (4) An increase in the vulcanization temperature, and therefore a shortening of the vulcanizing time, has only an insignificant effect on the freezing-resistance of rubber compounds. (5) The freezing effect increases as the temperature is lowered. (6) An entire loss of the elastic properties of vulcanized rubber takes place for the lower initial elongations at a temperature of —70° C; for higher elongations; however, they are still retanied at this temperature in a very small degree. (7) “Pure” rubber compounds have a much greater resistance to freezing than loaded ones. (8) The minimum susceptibility to freezing for loaded compounds is obtained with those that are slightly overvulcanized. At the higher elongations this minimum is distinctly shifted into the region of overvulcanization. (9) Softeners have in general no effect in reducing susceptibility to freezing. (10) The use of phenyl-β-naphthylamine has no effect on the susceptibility to freezing. (11) The aging of rubber, even when producing 40% of loss of tensile product, has no effect in lowering its resistance to freezing either at −10° or −60° C. and at initial elongations of from 100 to 400%. On the other hand, the resistance to freezing of aged samples is less at temperatures of −40° and −50° C. with initial elongations of 100 to 200% ; at an initial elongation of 300% they show almost no change in relation to unaged samples, while at an elongation of 400% they show a distinct increase in resistance to freezing. (12) Airplane and balloon shock-absorbers of “pure” rubber compounds possess, within the limits of their elongation during use, even at a temperature of — 40° C, quite insignificant susceptibility to freezing. An entire loss of their elastic properties occurs at −70° C. (13) Keeping airplanes in improvised sheds in winter time even at −20° C. has practically no effect on the usefulness of rubber shock-absorbers.

The Impact Resiliometer

1934 ◽  
Vol 7 (3) ◽  
pp. 591-598 ◽  
Author(s):  
Paul Lüpke
Keyword(s):  
Elastic Properties ◽  
Physical Science ◽  
Sustained Load ◽  
Plastic Properties ◽  
Dual Nature ◽  
Hardness Tester ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
The Impact ◽  
Average User

Abstract Original Purpose The writer's first conception of an instrument for quickly measuring the resilience of rubber samples arose in connection with the basic idea for and development of the present A.S.T.M. hardness tester, in an endeavor to provide a reproducible means of measuring and expressing those properties of rubber compounds superficially apparent to the average user. It seemed that if the resistance to pressure (indenting or flexing) and the pressure, or force, of recovery, of a sample were duplicated, the article produced would “feel” the same as the sample, and under normal conditions of use would act mechanically the same. Nature of Problem This problem of measurement, as is generally known, is complicated by the time-hysteresis characteristic of vulcanized rubber compounds, arising through a dual nature, and causing them to manifest both elastic and plastic properties. Any instrument which applies load momentarily measures the almost purely elastic properties, while one which applies a more or less sustained load measures elastic properties modified by the material's partially plastic nature. These ideas are expressed from commercial and industrial viewpoints without regard to their possible deviations from the strict definitions accepted in physical science.

The Testing of Rubber at Low Temperatures

1939 ◽  
Vol 12 (2) ◽  
pp. 365-369 ◽  
Author(s):  
J. H. Carrington
Keyword(s):  
Low Temperatures ◽  
Point Of View ◽  
Published Data ◽  
Great Success ◽  
Suspension Systems ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Resistance To Oxidation ◽  
Extreme Cold ◽  
Available Information

Abstract Developments in modern compounding have in the last few years undoubtedly improved the general properties of vulcanized rubber. Ever-widening fields of application of rubber goods have extended the range of temperature over which rubber is expected to retain its properties. The search for rubber compounds that shall have greater resistance to oxidation, heat, oil and so forth has certainly been pushed forward with great success, but progress in the other direction, namely, towards rubber compounds resistant to extreme cold, does not appear to have been so rapid. In this country we do not experience the extreme cold which occurs in the upper atmosphere and in regions nearer the poles, but rubber suspension systems, etc., as used in ships in polar latitudes or vessels transporting foodstuffs, railway components of many kinds and the numerous rubber parts used in the construction of aircraft all suffer to some extent from loss of resilience when exposed to cold conditions. It therefore seems just as necessary to compound with a view to resisting changes induced by freezing as we normally do to resist heat. With this end in view it was decided to make a critical review of published data on the effect of low temperatures on rubber to serve as a guide to further practical work. As is to be expected, those countries experiencing great cold have already carried out considerable investigation, but the available information is fairly widely distributed, and no doubt there is much work of a private nature which has never been published. It will be convenient, in the summary which follows, to indicate the most important information under headings relating to the chief properties of rubber. As is so frequently the case, physical results have been obtained on mixings of unstated composition or state of vulcanization, or on mixings that are simple, no doubt, from the theoretical standpoint but almost unusual from the practical point of view.

Low temperature acclimation and legacy effects of summer water deficits in olive freezing resistance

2021 ◽  
Author(s):  
Nadia S Arias ◽  
Fabián G Scholz ◽  
Guillermo Goldstein ◽  
Sandra J Bucci
Keyword(s):  
Plant Growth ◽  
Water Deficit ◽  
Low Temperatures ◽  
Cell Damage ◽  
Leaf Water ◽  
Leaf Nitrogen Content ◽  
Legacy Effects ◽  
Freezing Resistance ◽  
Lower Growth ◽  
Water Deficits

Abstract Low temperatures and drought are the main environmental factors affecting plant growth and productivity across most of the terrestrial biomes. The objective of this study was to analyze the effects of water deficits before the onset of low temperatures in winter to enhance freezing resistance in olive trees. The study was carried out near the coast of Chubut, Argentina. Plants of five olive cultivars were grown out-door in pots and exposed to different water deficit treatments. We assessed leaf water relations, ice nucleation temperature (INT), cell damage (LT50), plant growth and leaf nitrogen content during summer and winter in all cultivars and across water deficit treatments. Leaf INT and LT50 decreased significantly from summer to winter within each cultivar and between treatments. We observed a trade-off between resources allocation to freezing resistance and vegetative growth, such that an improvement in resistance to sub-zero temperatures was associated to lower growth in tree height. Water deficit applied during summer increased the amount of osmotically active solutes and decreased the leaf water potentials. This type of legacy effects persists during the winter after the water deficit even when treatment was removed, because of natural rainfalls.

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.

Gebruiksaspecten van het uitroeppartikel wat in het Nederlands en Fries

2020 ◽  
Vol 136 (4) ◽  
pp. 189-209
Author(s):  
Henk Wolf
Keyword(s):  
The Core ◽  
The Difference ◽  
Lexical Phrase ◽  
High Degree ◽  
Lexical Phrases

Abstract Both Dutch and (West) Frisian make use of the exclamative particle wat (‘how’), that adds an element of surprise about a high degree of something to the semantics of the sentence. In this paper I will first show the similarities between the use of the particle in the two languages. I will demonstrate that, in Dutch, its use is largely confined to constructions that are semantically scalable, whereas in Frisian this restriction is far less strict. I will explain the difference by showing that Dutch wat is a syntactic amplifier of lexical phrases, whereas Frisian wat has developed into a pragmatic amplifier of the core predicate. I will try to account for that difference by showing how homophonous words absent in Dutch are likely to have influenced the use of Frisian wat, and how Dutch prosody strengthens the connection between wat and the amplified lexical phrase, whereas Frisian prosody weakens it. Finally, I will show that the system described as ‘Frisian’ is occasionally found in varieties of Dutch too

The Oil Resistance of Rubber. I Study of the Swelling of Vulcanized Rubber

1936 ◽  
Vol 9 (1) ◽  
pp. 70-73
Author(s):  
Yoshio Tanaka ◽  
Shû Kambara ◽  
Jirô Noto
Keyword(s):  
Molecular Structure ◽  
Elastic Properties ◽  
Mixed Solvents ◽  
Experimental Results ◽  
Stress Strain ◽  
Oil Resistance ◽  
Effect Of Solvents ◽  
Vulcanized Rubber

Abstract To study the effect of solvents on the elastic properties of vulcanized rubber, the following three points were investigated. 1. The swelling maximum obtained by various mixed solvents. 2. The stress-strain curves of rubber swollen to different degrees. 3. Time-swelling and time-deswelling curves. The spiral theory of molecular structure of rubber proposed by Fikentscher and Mark is utilized to explain the experimental results.

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