Stress-Temperature Relations in a Pure-Gum Vulcanizate of Natural Rubber

1945 ◽  
Vol 18 (2) ◽  
pp. 367-379 ◽  
Author(s):  
Lawrence A. Wood ◽  
Frank L. Roth
Keyword(s):  
Natural Rubber ◽  
Constant Temperature ◽  
Considerable Importance ◽  
Tabular Form ◽  
Stress Strain ◽  
Time Relaxation ◽  
Relaxation Temperature ◽  
Straight Lines ◽  
Short Time

Abstract Stress-temperature relations at constant elongation have been investigated for a pure-gum vulcanizate of natural rubber. The rubber was first allowed to relax for about two hours at constant elongation and constant temperature to minimize the effects of short time relaxation of stress. The stress, except under special conditions, was changing very little at the end of this time. The stress-temperature relations for temperatures below the relaxation temperature could be represented by straight lines. The values of the slopes and intercepts of these lines are presented in tabular form. The stresses at the end of the relaxations were used as the basis of stress-strain curves. Crystallization was found to be an easily-recognized factor of considerable importance in the interpretation of the results.

scholarly journals Preparation and stress-strain behavior of in-situ epoxidized natural rubber/SiO2 hybrid through a sol-gel method

2018 ◽  
Vol 12 (2) ◽  
pp. 180-185 ◽  
Author(s):  
S. M. Li ◽  
T. W. Xu ◽  
Z. X. Jia ◽  
B. C. Zhong ◽  
Y. F. Luo ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Sol Gel ◽  
Epoxidized Natural Rubber ◽  
Stress Strain ◽  
Gel Method ◽  
Sol Gel Method ◽  
Strain Behavior

Influence of Crosslink Characteristics Induced by Aromatic-Based Antioxidants on the Swelling and Stress-Strain Behavior of Natural Rubber Vulcanizates

2003 ◽  
Vol 76 (2) ◽  
pp. 334-347 ◽  
Author(s):  
Tarek M. Madkour ◽  
Rasha A. Azzam
Keyword(s):  
Natural Rubber ◽  
Crosslinking Agent ◽  
Oxidative Degradation ◽  
Thermal Oxidative Degradation ◽  
Stress Strain ◽  
Strain Behavior ◽  
Strain Induced Crystallization ◽  
Elastomeric Chains ◽  
Natural Rubber Vulcanizates ◽  
Induced Crystallization

Abstract Stress-strain measurements were performed on dry and swollen natural rubber vulcanizates prepared using both sulfur as the crosslinking agent and aromatic-based bound antioxidants acting as a second crosslinking agent. The aromatic-based antioxidants were synthesized and analyzed spectroscopically in order to relate the final behavior of the vulcanizates to the nature of the crosslink characteristics. The anomalous upturn in the modulus values of these networks in response to the imposed stress was shown to persist in the dry as well as the swollen state. Since the swollen elastomeric chains cannot undergo a strain-induced crystallization, the abnormal upturns in the modulus values in an absence of a filler were explained on the basis of the limited extensibility of the short chains of networks prepared using two different crosslinking agents in line with earlier modeling predictions. Remarkably, the swelling experiments revealed the increase in the crosslink density of the networks in the early stages of the thermal oxidative degradation procedure indicating a post-cure of the chemically bound antioxidants to the elastomeric chains, which incidentally corresponds to a maximum in the modulus values of the networks. The rheological and other mechanical properties such as the hardness were shown not to have been affected as a result of the incorporation of the chemically bound antioxidants.

Vibration Properties of Rubberlike Materials Dependence on Temperature

1943 ◽  
Vol 16 (2) ◽  
pp. 400-416 ◽  
Author(s):  
R. B. Stambaugh
Keyword(s):  
Internal Friction ◽  
Natural Rubber ◽  
Critical Temperatures ◽  
Cohesive Forces ◽  
Exponential Law ◽  
Vibration Properties ◽  
Inverse Effect ◽  
Similar Materials ◽  
Straight Lines ◽  
Rubberlike Materials

Abstract 1. The vibration modulus and resilience are independent of the frequency of vibration if the temperature is constant. 2. The internal friction is approximately inversely proportional to the frequency. 3. The modulus decreases as temperature increases. Curves for synthetic stocks at high temperatures are not very different from those of rubber at low temperatures. 4. Resilience rises linearly with temperature. Rubber shows a transition from one slope to another at about 25° C. 5. The dependence of the internal friction of rubber and similar materials on temperature follows the same exponential law as the viscosity of liquids. At certain critical temperatures sudden changes occur in the cohesive forces, which cause a transition from one curve to another. For the natural rubber sample this occurs at about 17° C. 6. The amplitude of vibration has a large inverse effect on the modulus and friction, which cannot be explained by the temperature rise of the sample due to heat generated in it. The effect may be due to nonlinearity of the stress-strain curves. 7. Modulus and friction are affected by temperature in the same way, indicating the dependence of both on some fundamental characteristic of the molecular structure. Natural rubber requires two straight lines for representation on the modulus-friction plot, the junction occurring at about 25° C.

DEPENDENCE OF THE ONSET OF STRAIN-INDUCED CRYSTALLIZATION OF NATURAL RUBBER AND ITS SYNTHETIC ANALOGUE ON CROSSLINK AND ENTANGLEMENT BY USING SYNCHROTRON X-RAY

2017 ◽  
Vol 90 (4) ◽  
pp. 728-742 ◽  
Author(s):  
Watcharin Sainumsai ◽  
Shigeyuki Toki ◽  
Sureerut Amnuaypornsri ◽  
Adun Nimpaiboon ◽  
Jitladda Sakdapipanich ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Crosslink Density ◽  
Inhomogeneous Material ◽  
Synthetic Analogue ◽  
Stress Strain ◽  
X Ray ◽  
Stress Strain Relation ◽  
Strain Induced Crystallization ◽  
Induced Crystallization ◽  
Flow Induced Crystallization

ABSTRACT Strain-induced crystallization (SIC) and stress–strain relations of varied crosslink structures and varied crosslink densities of vulcanized natural rubber (NR), vulcanized synthetic polyisoprene rubber (IR), and un-vulcanized natural rubber are compared using a synchrotron X-ray. The onset strain of SIC does not depend on crosslink density and crosslink structures. Un-vulcanized NR shows a smaller onset strain of SIC than that of vulcanized NR. Therefore, entanglements in NR are pivot points to induce SIC, just as entanglements in semi-crystalline plastics induce flow-induced crystallization (FIC). During deformation, complicated phenomena occur simultaneously such as cavitation, crosslink breakdown, SIC with temperature upturn, and limited extensibility of chains between crosslinks, because rubber is a significantly inhomogeneous material. It is still difficult to evaluate the contribution of SIC to stress-upturn of the stress–strain relation of rubber.

Tensile Stress—Strain and Stress Relaxation Behavior of Raw Elastomers Using a High Speed Tester

1974 ◽  
Vol 47 (2) ◽  
pp. 307-317 ◽  
Author(s):  
H. H. Bowerman ◽  
E. A. Collins ◽  
N. Nakajima
Keyword(s):  
Stress Relaxation ◽  
High Speed ◽  
Strain Rates ◽  
Time Behavior ◽  
Stress Strain ◽  
Strain Behavior ◽  
Relaxation Measurements ◽  
Ultimate Properties ◽  
Short Time ◽  
Acrylonitrile Copolymers

Abstract A high-speed, tensile-testing device was used to determine the stress—strain behavior of uncompounded butadiene—acrylonitrile copolymers over a range of temperatures and deformation rates. The strain rates were varied from 267 to 26,700 per cent/sec and the temperature was varied from 25 to 97° C. The high-speed tester was also used for stress—relaxation measurements by applying the strain nearly instantly in conformity with theoretical requirements in order to obtain the short time behavior. The WLF equation was obtained from the stress—relaxation data and then used to reduce the ultimate properties to one temperature over four decades of the strain rates. The ultimate properties could be represented by a failure envelope similar to those obtained for vulcanizates.

Effects of plasticizers on the strain-induced crystallization and mechanical properties of natural rubber and synthetic polyisoprene

RSC Advances ◽  
2015 ◽  
Vol 5 (15) ◽  
pp. 11317-11324 ◽  
Author(s):  
Yueqing Ren ◽  
Suhe Zhao ◽  
Qian Yao ◽  
Qianqian Li ◽  
Xingying Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Stress Strain ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Effects of different type of plasticizers on the strain-induced crystallization and stress–strain curves of crystallizable rubber.

Analysis of stress-strain characteristics of composite films based on polyethylene polymers with natural rubber

2017 ◽  
Author(s):  
I. A. Varyan ◽  
E. E. Mastalygina ◽  
N. N. Kolesnikova ◽  
A. A. Popov ◽  
E. O. Perepelitsina
Keyword(s):  
Natural Rubber ◽  
Composite Films ◽  
Stress Strain

Entanglements and Networks to Strain-Induced Crystallization and Stress–Strain Relations in Natural Rubber and Synthetic Polyisoprene at Various Temperatures

2013 ◽  
Vol 46 (13) ◽  
pp. 5238-5248 ◽  
Author(s):  
Shigeyuki Toki ◽  
Justin Che ◽  
Lixia Rong ◽  
Benjamin S. Hsiao ◽  
Sureerut Amnuaypornsri ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Stress Strain ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

A Modified Fictive Stress Model for Zr55Al10Ni5Cu30 Bulk Metallic Glass in Supercooled Liquid Region by Introducing a Time Relaxation Factor

2014 ◽  
Vol 893 ◽  
pp. 449-456
Author(s):  
Zhi Hui Ma ◽  
Hong Juan Su ◽  
Xiang Huai Dong
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Stress Model ◽  
Stress Strain ◽  
Time Relaxation ◽  
Relaxation Factor ◽  
Nonlinear Viscoelastic

Linear and nonlinear viscoelastic behaviors of a Zr55Al10Ni5Cu30bulk metallic glass are investigated through experiments and described by the fictive stress model. Systematic deviations between the predicted stress-strain curves by fictive stress model and by the experimental results were found. In order to describe the flow stress curves of the Zr55Al10Ni5Cu30BMG at different temperatures and strain rates in the supercooled liquid region more precisely, the fictive stress model was modified. The parameters of the model were optimized by the genetic algorithm, and a time relaxation factor Z' was introduced. The comparisons of the predicted compressive stress-strain curves and extrusion load-punch stroke curve by the modified fictive stress model with the experimental data show good agreements.

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