Extensibility of Black Filled Elastomers

1986 ◽  
Vol 59 (2) ◽  
pp. 187-203 ◽  
Author(s):  
Asahiro Ahagon
Keyword(s):  
Wide Temperature Range ◽  
Crosslink Density ◽  
Constant Modulus ◽  
Temperature Range ◽  
Filled Elastomers ◽  
Extension Ratio ◽  
Material Evaluation ◽  
Empirical Relations ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Abstract Unique empirical relations are found to exist between the extension ratio at break λb and the crosslink density ν λb ∝ ν−0.75 in the absence of gross strain induced crystallization, and λb ∝ ν−0.2 in the presence of gross strain-induced crystallization. With black-filled elastomers, the modulus at 100% strain, M100, is proportional to the crosslink density over a wide temperature range. Thus, unique empirical relations exist between λb and M100 of black-filled elastomers; λb ∝ M100−0.75 in the absence of gross strain-induced crystallization, and λb ∝ M100−0.2 in the presence of gross strain-induced crystallization. The proportionality constants can be used as convenient measures of the extensibility in material evaluation on a constant modulus basis.

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.

STRAIN-INDUCED CRYSTALLIZATION AND MECHANICAL PROPERTIES OF NBR COMPOSITES WITH CARBON NANOTUBE AND CARBON BLACK

2012 ◽  
Vol 85 (2) ◽  
pp. 207-218 ◽  
Author(s):  
Sang-Ryeoul Ryu ◽  
Jong-Whan Sung ◽  
Dong-Joo Lee
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Nanotube ◽  
Carbon Black ◽  
Scanning Calorimetry ◽  
Multiwalled Carbon ◽  
Extension Ratio ◽  
The Matrix ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Abstract The mechanical properties and strain-induced crystallization (SIC) of elastomeric composites were investigated as functions of the extension ratio (λ), multiwalled carbon nanotube (CNT) content, and carbon black (CB) content. The tensile strength and modulus gradually increase with increasing CNT content when compared with the matrix and the filled rubbers with same amount of CB. Both properties of rubber with CB and CNT show the magnitude of each CNT and CB component following the Pythagorean Theorem. The ratio of tensile modulus is much higher than that of tensile strength because of the CNT shape/orientation and an imperfect adhesion between CNT and rubber. The tensile strength and modulus of the composite with a CNT content of 9 phr increases up to 31% and 91%, respectively, compared with the matrix. Differential scanning calorimetry (DSC) analysis reveals that the degree of SIC increases with an increase in CNT content. Mechanical properties have a linear relation with the latent heat of crystallization (LHc), depending on the CNT content. As the extension ratio increases, the glass-transition temperature (Tg) of the composite increases for CB- and CNT-reinforced cases. However, the LHc has a maximum of λ = 1.5 for the CNT-reinforced case, which relates to a CNT shape and an imperfect adhesion with rubber. Based on these results, the reinforcing mechanisms of CNT and CB are discussed.

The Role of Filler Properties in the Creep Deformation of Filled Elastomers

1983 ◽  
Vol 56 (2) ◽  
pp. 465-480
Author(s):  
J. L. Thiele ◽  
R. E. Cohen
Keyword(s):  
Carbon Black ◽  
Creep Deformation ◽  
High Strain ◽  
Filled Elastomers ◽  
Filled Elastomer ◽  
Strain Mechanism ◽  
Sensitive Tool ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Abstract The use of the creep T-jump experiment as a sensitive tool for elucidating the mechanistic behavior during the deformation of a complex material such as the carbon black filled elastomer has been illustrated. The activation energy for creep was determined as a function of stress for various vulcanizates. The effects of the choice of elastomer, and of variations in surface chemistry, structure, and loading of the filler, were studied. The T-jump results combined with electrical conductivity measurements confirmed the presence of a carbon black network which is considerably involved in the creep deformation process at low strain but not at high strain. In NR vulcanizates, there is a high-strain mechanism not observed in SBR vulcanizates; presumably strain-induced crystallization is responsible for the NR behavior. Oxidation of filler surfaces had essentially no effect on the creep deformation mechanisms, suggesting that, during creep, slippage of elastomers along the surface does not occur to any great extent for conventional or oxidized surfaces.

The Behavior of Carbon Black-Filled Natural Rubber under High Strain Rates3

2006 ◽  
Vol 34 (2) ◽  
pp. 119-134 ◽  
Author(s):  
Syeda A. Hussain ◽  
Michelle S. Hoo Fatt
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Natural Rubber ◽  
Strain Rate ◽  
Characteristic Relaxation Time ◽  
Dynamic Tensile Strength ◽  
Extension Ratio ◽  
Strain Induced Crystallization ◽  
Quasistatic Loading ◽  
Induced Crystallization

Abstract Tensile tests were conducted to obtain the deformation and failure characteristics of unfilled natural rubber (NR) and natural rubber with 25, 50, and 75 phr of N550 carbon black filler under quasistatic and dynamic loading conditions. The quasistatic tests were performed on an electromechanical INSTRON machine, while the dynamic test data were obtained from tensile impact experiments using a Charpy impact apparatus. In general, the modulus of the stress-extension ratio curves increases with increasing strain rate up to about 407, 367, 346, and 360 s−1 for unfilled, and 25, 50, and 75 phr for filled NR, respectively. Above these strain rates, the unfilled and filled natural rubber stress-extension ratio curves remained unchanged. The modulus increased with increasing strain rate because there was little time for stress relaxation. Above a critical strain rate, no change in modulus was observed because the time of the experiment was short compared to the lowest characteristic relaxation time of the material. Dynamic stress-extension ratio curves did not have the very sharp upturn at break, which is observed from strain-induced crystallization in natural rubber under quasistatic loading. Strain-induced crystallization appeared to be suppressed at high rates of loading. In fact, the highest dynamic tensile strength for the 25- and 50-phr carbon black-filled natural rubbers was smaller than those under quasistatic loading, while the highest dynamic tensile strength of the 75-phr carbon black-filled NR was greater than that in the static test. This indicated that high amounts of carbon black fillers will impede strain-induced crystallization in natural rubber.

Intrinsic Defects and the Failure Properties of cis-1,4-Polyisoprenes

1996 ◽  
Vol 69 (4) ◽  
pp. 591-599 ◽  
Author(s):  
I. S. Choi ◽  
C. M. Roland
Keyword(s):  
Natural Rubber ◽  
Strain Energy ◽  
Crosslink Density ◽  
Crystallization Behavior ◽  
Inverse Correlation ◽  
Flaw Size ◽  
Dominant Effect ◽  
Strain Induced Crystallization ◽  
Failure Properties ◽  
Induced Crystallization

Abstract Inherent flaw sizes were determined from fatigue lifetimes, and from the crack length dependence of the strain energy to break, for four cis-1,4-polyisoprenes compounded to have the same crosslink density and low strain hysteresis. Both techniques indicated that the flaws intrinsic to guayule rubber (GR), and to a lesser extent conventional natural rubber, are larger than those found in deproteinized NR. This result may not be surprising; however, the failure properties of the elastomers, expected to depend on flaw size, were surprising. The guayule rubber and a natural rubber of relatively low purity (SMR-10) had the highest tensile strengths, tear strengths, breaking energies, and fatigue lifetimes, while DPNR exhibited the worst failure properties. Such an inverse correlation between flaw size and failure performance is due to the dominant effect of strain-induced crystallization. GR and SMR-10 have the highest propensity for strain-induced crystallization, while DPNR is the least strain-crystallizable. Interestingly, all rubbers exhibited the same isotropic crystallization behavior.

Fibre-optic temperature sensor with wide temperature range characteristics

1987 ◽  
Vol 134 (5) ◽  
pp. 291 ◽  
Author(s):  
K.T.V. Grattan ◽  
J.D. Manwell ◽  
S.M.L. Sim ◽  
C.A. Willson
Keyword(s):  
Wide Temperature Range ◽  
Temperature Sensor ◽  
Fibre Optic ◽  
Temperature Range

Enabling highly reversible sodium metal cycling across a wide temperature range with dual-salt electrolytes

2021 ◽  
Author(s):  
Akila C. Thenuwara ◽  
Pralav P. Shetty ◽  
Neha Kondekar ◽  
Chuanlong Wang ◽  
Weiyang Li ◽  
...  
Keyword(s):  
Wide Temperature Range ◽  
High Energy ◽  
Liquid Electrolyte ◽  
Metal Cycling ◽  
Temperature Range ◽  
Sodium Metal ◽  
Wide Range

A new dual-salt liquid electrolyte is developed that enables the reversible operation of high-energy sodium-metal-based batteries over a wide range of temperatures down to −50 °C.

Magnetic anomalies, chemical and magnetic properties at wide temperature range (15–1000 K) in LiSrxFe5-xO8 (x = 0, 0.025, 0.05)

2021 ◽  
Vol 859 ◽  
pp. 158290
Author(s):  
S. Udhayakumar ◽  
G. Jagadish Kumar ◽  
E. Senthil Kumar ◽  
M. Navaneethan ◽  
K. Kamala Bharathi
Keyword(s):  
Magnetic Properties ◽  
Wide Temperature Range ◽  
Magnetic Anomalies ◽  
Temperature Range
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