Microstructural Changes in the Crack Tip Region of Carbon-Black-Filled Natural Rubber

1987 ◽  
Vol 60 (5) ◽  
pp. 910-923 ◽  
Author(s):  
D. J. Lee ◽  
J. A. Donovan
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Fracture Resistance ◽  
Crack Tip ◽  
Microstructural Changes ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Abstract CB facilitates strain-induced crystallization and increases the size of the crystallized zone at the stressed crack tip. Both effects are major reinforcement mechanisms that increase the fracture resistance of CB-reinforced NR.

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.

Strain-induced crystallization around a crack tip in natural rubber under dynamic load

Polymer ◽  
2013 ◽  
Vol 54 (22) ◽  
pp. 6200-6205 ◽  
Author(s):  
Karsten Brüning ◽  
Konrad Schneider ◽  
Stephan V. Roth ◽  
Gert Heinrich
Keyword(s):  
Natural Rubber ◽  
Dynamic Load ◽  
Crack Tip ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Multiphase Systems

1997 ◽  
Author(s):  
Burak Erman ◽  
James E. Mark
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Permanent Deformation ◽  
Second Phase ◽  
Metallic Particles ◽  
Precipitated Silica ◽  
Strain Induced Crystallization ◽  
The Subject ◽  
Filler Reinforcement ◽  
Induced Crystallization

One class of multiphase elastomers are those capable of undergoing strain-induced crystallization, as was discussed separately in chapter 12. In this case, the second phase is made up of the crystallites thus generated, which provide considerable reinforcement. Such reinforcement is only temporary, however, in that it may disappear upon removal of the strain, addition of a plasticizer, or increase in temperature. For this reason, many elastomers (particularly those which cannot undergo strain-induced crystallization) are generally compounded with a permanent reinforcing filler. The two most important examples are the addition of carbon black to natural rubber and to some synthetic elastomers, and the addition of silica to siloxane rubbers. In fact, the reinforcement of natural rubber and related materials is one of the most important processes in elastomer technology. It leads to increases in modulus at a given strain, and improvements of various technologically important properties, such as tear and abrasion resistance, resilience, extensibility, and tensile strength. There are also disadvantages, however, including increases in hysteresis (and thus of heat buildup) and compression set (permanent deformation). Another problem in this area is the absence of a reliable molecular theory for filler reinforcement, in general, and even simple molecular pictures of the origin of the reinforcement are lacking. The subject is not even discussed in what has long been the standard reference book on rubberlike elasticity! On the other hand, there is an incredible amount of relevant experimental data available, with most of these data relating to reinforcement of natural rubber by carbon black. Recently, however, other polymers such as poly(dimethylsiloxane), and other fillers, such as precipitated silica, metallic particles, and even glassy polymers, have become of interest. These studies have shown that materials which act as fillers can vary substantially with respect to the chemical nature of their surfaces, and probably most solid, finely divided materials may advantageously be incorporated into an elastomer. In fact, this is one of the ways the crystallites discussed in chapter 12 improve the mechanical properties of an elastomer. Experimental evidence indicates that the extent of the reinforcement depends strongly on particle size.

Strain-induced crystallization behaviour of natural rubbers from guayule and rubber dandelion revealed by simultaneous time-resolved WAXD/tensile measurements: indispensable function for sustainable resources

RSC Advances ◽  
2016 ◽  
Vol 6 (98) ◽  
pp. 95601-95610 ◽  
Author(s):  
Yuko Ikeda ◽  
Preeyanuch Junkong ◽  
Takumi Ohashi ◽  
Treethip Phakkeeree ◽  
Yuta Sakaki ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Crystallization Behaviour ◽  
Time Resolved ◽  
Sustainable Resources ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Guayule and rubber dandelion natural rubbers are useful alternatives forHeveanatural rubber in terms of their strain-induced crystallization behaviours.

Thermomechanics of strain-induced crystallization in natural rubber under cyclic loading

PAMM ◽  
2017 ◽  
Vol 17 (1) ◽  
pp. 493-494
Author(s):  
Lutz Zybell ◽  
Jan Domurath ◽  
Konrad Schneider
Keyword(s):  
Cyclic Loading ◽  
Natural Rubber ◽  
Strain Induced Crystallization ◽  
Induced Crystallization
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