Author: Richard A. Thoman (Jr.)
Publisher:
ISBN:
Category : Brittleness
Languages : en
Pages : 8

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Book Description

Author: Bukhina
Publisher: CRC Press
ISBN: 9047422422
Category : Technology & Engineering
Languages : en
Pages : 193

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Book Description
This book focuses on the effect the composition of rubbers and the conditions of their processing have on low-temperature resistance. It considers the nature and development of two physical processes, glass transition and crystallization, determining low-temperature behavior of elastomers. The book addresses the effects of deformation, pressure, an

Author: John W. Liska
Publisher:
ISBN:
Category : Low temperature engineering
Languages : en
Pages : 20

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Book Description
Up to the time of the beginning of the recent World War, comparatively little was known about the low-temperature characteristics of rubber, in spite of the fact that a number of investigators (1-16) had studied the subject. This can be at least partly explained by the fact that natural rubber, the only important elastomer known at that time, retained its flexibility over a rather wide range of temperatures extending down to -70 F. or even lower. Applications requiring flexibility or elasticity at temperatures lower than -70 or -75 F. were relatively rare, and, as a result, much of the work on this subject was largely academic in nature. Two important factors quickly changed the emphasis from academic to highly practical considerations. First of all, aircraft ceilings were being continually raised, making it necessary for tires, airplane de-icers, engine mountings, and tubing to withstand lower and lower temperatures. Secondly, it was soon discovered that the synthetic rubbers which had to be substituted for natural rubber, without exception, became inflexible or even brittle at temperatures considerably higher than natural rubber. Other factors also contributed to the demand for knowledge of the behavior of elastomers at low temperatures. Tanks and trucks had to operate efficiently in the arctic as well as in the tropic regions. Airplanes, tanks, and ships carried more and more sensitive equipment for communication and direction of gunfire, all of which had to be mounted on vibration-absorbing supports in order to retain their accuracy during actual operations. Then too, in order to decrease transmission of vibration and shock as much as possible, rubber-like materials were used more and more as prime mounts for vehicles, that is, in the form of tank treads, tires, and bogie rollers on tanks. The majority of tests developed in recent years (17-26) to measure low-temperature serviceability, fall roughly into two classes: one, a method for determining the so-called brittle-point temperature; and, two means for measuring the rate of stiffening or hardening with decrease in temperature. Some atempts have also been made to measure physical properties under dynamic conditions at low temperatures (24), but so far these methods have not been developed very completely nor have they received any general acceptance. For these reasons, they will not be discussed in any detail in this paper, though their importance, when more fully developed, should not be minimized.

Author: Paul E. Gatza
Publisher:
ISBN:
Category :
Languages : en
Pages : 26

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Book Description
The report covers an evaluation of the potential for end-item applications of several elastomers purported to be both inherently ozone resistant and serviceable at temperatures as low as -65F. Using specification requirements detailed in Specifications MIL-I-3930C and MIL-R-14328A as guidelines, results of physical testing and compound development studies on ethylene-propylene, modified butyl, and propylene oxide elastomers are compared with results obtained on a compound of SB-R 1023. Although the latter is not an inherently ozone-resistant rubber, it is acceptable for use at -65F. Other physical characteristics such as heat, oxygen, water and weather resistance, deemed essential for satisfactory performance in general-purpose applications, were determined for these elastomers and are analyzed and discussed. (Author).

Author: AMS CE Elastomers Committee
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
To ensure success in design of elastomeric parts for use at low temperature, the design engineer must understand the peculiar properties of rubber materials at these temperatures.There are no static applications of rubber. The Gaussian theory of rubber elasticity demonstrates that the elastic characteristic of rubber is due to approximately 15% internal energy and the balance, 85%, is entropy change. In other words, when an elastomer is deformed, the elastomer chain network is forced to rearrange its configuration thereby storing energy through entropy change. Thermodynamically, this means that rubber elasticity is time and temperature dependent (Reference 25).The purpose of this report is to provide guidance on low temperature properties of rubber with the terminology, test methods, and mathematical models applicable to rubber, and to present some practical experience. In this way, it is hoped that mistakes can be avoided, particularly in selection of rubber materials, enabling the design engineer to weigh low-temperature material properties together with the many other factors involved in the design process. AIR1387C is now due for review. The template has been revised to meet the document standards of SAE. The addition of glass transition (Tg) and temperature retraction tables, new low temperature hydrocarbon and fluorocarbon elastomers, and new test methods to characterize low temperature properties of elastomers has been made to the last revision.

Author:
Publisher: iSmithers Rapra Publishing
ISBN: 9781859575109
Category : Science
Languages : en
Pages : 246

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Book Description
There is an exciting mix in these proceedings from both material suppliers and end users, who have discussed test and formulation data. There is an overview paper on the markets for rubbers from the International Rubber Study Group. There is also a new presentation on studies of food contact applications of high performance elastomers, with migration data available.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 262

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Book Description
The determination of the physical characteristics of elastomers at low temperatures has not been standardized within the rubber industry because the many and varied uses of rubber preclude the use of one specific test method. The standardization of test equipment and procedures for specification testing and Research and Development Evaluation, has not progressed sufficiently by the rubber industry or standardizing agencies such as the Society of Automotive Engineers or the American Society for Testing materials, to insure adequate low temperature performance. Since a large proportion of rubber goods is currently being manufactured for the military services, and since low temperature performance is manditory it becomes apparent that the military laboratories should take the lead in establishing adequate procurement specifications. It was for this purpose that the Conference on low temperature testing of elastomers was held. (MM).

Author: K. E. Kear
Publisher: iSmithers Rapra Publishing
ISBN: 9781859574331
Category : Science
Languages : en
Pages : 158

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Book Description
Thermoplastic elastomers (TPEs) have the elastic behaviour of rubber and the processability of thermoplastics. The Freedonia Group has forecast that demand will expand by 6.4% per year to around 2.15 million tons in 2006. There is potential for these new, exciting materials to expand into the much larger thermoset rubber markets. This review includes comparisons between the two material types. There are three major types of TPE: block copolymers, rubber/plastic blends and dynamically vulcanised rubber/plastic alloys known as thermoplastic vulcanisates. The chemistry of these materials and how.

Author:
Publisher: iSmithers Rapra Publishing
ISBN: 9781859572337
Category : Elastomer
Languages : en
Pages : 142

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Book Description

Author: P. W. Dufton
Publisher: iSmithers Rapra Publishing
ISBN: 9781859573020
Category : Elastomers
Languages : en
Pages : 176

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Book Description
This report contains discussion of the different families of thermoplastic elastomer materials, and of the trends in material developments. The key end-use sectors are analysed in terms of material usage and future trends.