Effect of Degree of Elongation on Ozone Cracking of Rubbers

1959 ◽  
Vol 32 (1) ◽  
pp. 278-283
Author(s):  
Yu S. Zuev ◽  
S. I. Pravednikova
Keyword(s):  
Tensile Strength ◽  
Zinc Oxide ◽  
Natural Rubber ◽  
Butyl Rubber ◽  
Objective Method ◽  
Rubber Sample ◽  
Rate Of Growth ◽  
Gutta Percha ◽  
Effective Depth

Abstract It is known from the literature that there exists a socalled critical elongation at which disruption of the structure of rubbers under the influence of ozone is most severe. However, the available data concerning this problem are fairly contradictory. According to a number of statements the critical elongation is observed in the case of vulcanizates of natural rubber, but its estimation by different authors varies from 5 to 50%. Some authors consider that a critical elongation exists in the case of synthetic rubbers susceptible to attack by ozone, while others consider that no such characteristic exists. It is said that polychloroprene and butyl rubber do not possess this characteristic. However, none of these data can be regarded as reliable since in most cases ozone cracking of the rubbers was characterized by arbitrary methods, as a rule by the “degree of cracking” expressed by the number of marks. We have carried out a detailed investigation of the effect of the degree of elongation on ozone cracking of rubbers, the rate of growth of cracks being determined by an objective method based on the effective depth of the cracks calculated from the decrease of stress in the relaxed rubber sample when exposed to the action of ozone. The following rubbers—NK, SKS, neurite, SKN, and SKB were investigated in standard formulas, at optimum true tensile strength. Gutta-percha (elastic vulcanizate) and butyl rubber compositions in phr were: gutta-percha 100, MBT 0.8, sulfur 5; butyl rubber 100, stearine 3, MBT 0.65, thiuram disulfide 1.3, zinc oxide 5, sulfur 2.

scholarly journals Study the impact of A nanomixture of carbon black and clay on the mechanical properties of A series of irradiated natural rubber/ butyl rubber blend

2021 ◽  
Author(s):  
Dalal Alshangiti
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Black ◽  
Natural Rubber ◽  
Theoretical Models ◽  
Butyl Rubber ◽  
Nano Particles ◽  
Vinyl Silane ◽  
Link Density ◽  
The Impact

Abstract A series of natural rubber/ butyl rubber NR/IIR blend loaded with N660 carbon black CB and triethoxy vinyl silane treated clay nano particles (TCNP) were prepared using gamma irradiation in the presence of polyfunctional monomer, trimethylolpropane triacrylate (TMPTA). The effect of incorporating different content of N660 carbon black and 5 part per hundred of rubber (phr) of treated clay on the mechanical properties of the prepared nano composites have been investigated. The additions of TCNP into CB/ rubber composites markedly increase their tensile strength due to the increase of the cross-link density. These results indicated that the TCNP may be enclosed or trapped in the occluded structure of CB. The effect of CB and TCNP content on the tensile strength (σ), elongation at break (εb %) and modulus of elasticity (E, MPa) of natural rubber/ butyl rubber NR/IIR blend have been investigated. The incorporation of 5 phr of TCNP into 30 phr carbon black loaded NR/ IIR composites results in the increased tensile strength value by about 60%. Finally, theoretical models were used to interpret the experimental results.

Reinforcement of Natural Rubber with Silanized Precipitated Silica Nanofiller

2005 ◽  
Vol 78 (5) ◽  
pp. 793-805 ◽  
Author(s):  
A. Ansarifar ◽  
N. Ibrahim ◽  
M. Bennett
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Zinc Oxide ◽  
Reaction Mechanism ◽  
Energy Density ◽  
Natural Rubber ◽  
Elemental Sulfur ◽  
Stored Energy ◽  
Tear Strength ◽  
Precipitated Silica

Abstract The effect of a large amount of precipitated amorphous white silica nanofiller, pre-treated with bis[3-triethoxysilylpropyl-)tetrasulfide (TESPT), on the mechanical properties of a sulfur-cured natural rubber (NR) was studied. TESPT chemically adheres silica to rubber and also prevents silica from interfering with the reaction mechanism of sulfur-cure. The silica particles were fully dispersed in the rubber, which was cured primarily by using sulfur in TESPT, or, by adding a small amount of elemental sulfur to the cure system. The cure was also optimized by incorporating sulphenamide accelerator and zinc oxide into the rubber. The hardness, tear strength, tensile strength, and stored energy density at break of the vulcanizate were substantially improved when the filler was added. Interestingly, these properties were also enhanced when the rubber was cured primarily by using sulfur in TESPT.

scholarly journals Impact of a nanomixture of carbon black and clay on the mechanical properties of a series of irradiated natural rubber/butyl rubber blend

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 662-670
Author(s):  
Dalal M. Alshangiti
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Black ◽  
Natural Rubber ◽  
Theoretical Models ◽  
Butyl Rubber ◽  
Clay Nanoparticles ◽  
Vinyl Silane ◽  
Link Density ◽  
Cross Link Density

Abstract A series of natural rubber/butyl rubber NR/IIR blend loaded with N660 carbon black (CB) and triethoxy vinyl silane treated clay nanoparticles (TCNPs) were prepared using gamma irradiation in the presence of a polyfunctional monomer, trimethylolpropane triacrylate (TMPTA). The effect of incorporating different contents of N660 CB and five parts per hundred of rubber (phr) of treated clay on the mechanical properties of the prepared nanocomposites has been investigated. The addition of TCNP to CB/rubber composites markedly increase their tensile strength due to the increase of the cross-link density. These results indicated that the TCNP may be enclosed or trapped in the occluded structure of CB. The effect of CB and the TCNP content on the tensile strength (σ), elongation at break (ε b, %), and modulus of elasticity (E, MPa) of natural rubber/butyl rubber NR/IIR blend have been investigated. The incorporation of 5 phr of TCNP into 30 phr CB-loaded NR/IIR composites results in the increased tensile strength value by about 60%. Finally, theoretical models were used to interpret the experimental results.

The Effect of Pile Bombardment on Uncured Elastomers

1949 ◽  
Vol 22 (1) ◽  
pp. 138-147 ◽  
Author(s):  
W. L. Davidson ◽  
I. G. Geib
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Mineral Content ◽  
Control Sample ◽  
Butyl Rubber ◽  
Alpha Particles ◽  
High Concentrations ◽  
Ionizing Radiations ◽  
Rubber Stock

Abstract Previous work on the effects of ionizing radiations on hydrocarbons has established that four competitive processes are usually operative: (1) dehydrogenation, (2) condensation or polymerization, (3) hydrogenation (action of nascent hydrogen on any unsaturated matter present), (4) decomposition (C—C cleavage). The chain reacting nuclear pile offers an ideal means for subjecting relatively thick samples of matter (such as rubber) to uniformly high concentrations of radiation. Such studies on natural rubber, Butyl rubber, and polyisobutylene allow one to draw the following conclusions. 1. Uncured natural rubber undergoes a slight curing action when exposed to pile radiations. 2. Polyisobutylene samples are appreciably degraded by pile radiations. 3. The same effects as noted in (1) and (2) are greatly enhanced by secondary alpha particles, produced by an (n, α) reaction on boron (milled into the elastomer). However, even a 2-hour bombardment of natural rubber yields a product greatly inferior to sulfur vulcanizates. 4. Pile bombardment does not introduce measurable unsaturation in polyisobutylene and decreases the unsaturation in natural rubber but slightly. 5. A typical Butyl rubber stock is permanently degraded by pile irradiation, showing on cure reduced tensile strength compared to that of a control sample. 6. Natural rubber shows a weak but measurable radioactivity days after bombardment, probably because of its mineral content. Polyisobutylene is not appreciably active.

The Damping Properties of the Natural Rubber Filled with ZnO

2014 ◽  
Vol 912-914 ◽  
pp. 390-394 ◽  
Author(s):  
Yan Fang Zhao ◽  
Dan Liu ◽  
Shuang Quan Liao ◽  
Xiao Xue Liao ◽  
Sheng Bo Lin
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Zinc Oxide ◽  
Natural Rubber ◽  
Damping Properties ◽  
Tear Strength ◽  
Thermal Stability Of

The research on the mechanical properties and thermal stability of the natural rubber filled with different dosage of Zinc oxide (ZnO). The results showed that with the increase of the content of the ZnO, the tensile strength first increased, then decreased the, but the tear strength showed a trend of increase,the thermal stability had improved; When the amount of ZnO added was 9, damping performance was better.

Structural Features of Buna-S. Relation to Physical Properties

1945 ◽  
Vol 18 (1) ◽  
pp. 41-61
Author(s):  
A. R. Kemp ◽  
W. G. Straitiff
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Physical Properties ◽  
Structural Features ◽  
Polymer Chains ◽  
Polymerization Reaction ◽  
Gel Structure ◽  
Gutta Percha ◽  
Cross Linkage

Abstract The low tensile strength of Buna-S gum stocks is generally believed to be due to failure to obtain effective cross-linkage as the result of vulcanization with sulfur and accelerators. Combined with this is the complete absence of crystallization of Buna-S on stretching which, in the case of natural rubber, reinforces and strengthens the vulcanized gel structure. The absence of crystallization in Buna-S can be explained on the basis of nonsymmetry along the polymer chains. Strictly speaking, Buna-S is not a true polymer, for ozonolysis shows that the styrene units are not spaced evenly in the chain but are grouped together in some locations. Ozonolysis also has proved the presence of vinyl groups attached to the chain, resulting from the polymerization of butadiene in the 1,2 instead of the 1,4 position. These vinyl groups must be unevenly spaced along the chain, and mixed trans and cis isomers must be present. Figure 1 illustrates the chemical units present in Buna-S, rubber, and gutta-percha hydrocarbons. In a Buna-S copolymer containing 24.5 per cent of styrene, there are six butadiene to one styrene units. It appears that about one butadiene in five polymerizes in the 1,2 position in the chain. It should be emphasized that, in Buna-S, ozonolysis has shown that no regular order exists in the location of A, B, and C units in the polymer. An entire lack of symmetry in the positioning of these units in the chain would be expected in view of the nature of the polymerization reaction.

Strength of Amorphous and of Crystallizing Rubberlike Polymers

1946 ◽  
Vol 19 (1) ◽  
pp. 42-45 ◽  
Author(s):  
A. P. Aleksandrov ◽  
J. S. Lazurkin
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Butyl Rubber ◽  
Chemical Compositions ◽  
Butadiene Rubber ◽  
Linear Polymers ◽  
Elastic State ◽  
Natural Rubber Vulcanizates ◽  
Isoprene Rubber

Abstract The strengths of unloaded vulcanizates and the action of active fillers differ greatly according to the types of elastomers from which they are derived. These differences are not connected directly with the chemical compositions of the elastomers. Thus, for example, vulcanizates of natural rubber and synthetic isoprene rubber differ in strength in the ratio 10–15 to 1, whereas vulcanizates of Butyl rubber and of polychloroprene are very similar to natural rubber vulcanizates with respect to tensile strength. These differences in tensile strength cannot be ascribed directly to differences in structure of the chains, linear or branched; linear polymers of styrene and of methyl methacrylate “vulcanized” by small admixtures of butadiene-benzene or dimethacrylate-ethyleneglycol have, in the elastic state, tensile strengths which are just as low as those of unloaded vulcanizates of sodium-butadiene rubber or of isoprene rubber. The differences in tensile strength must, accordingly, be looked for in the different macroscopic properties of these polymers.

EFFECT OF IN SITU SURFACE-MODIFIED NANO–ZINC OXIDE ON THE STRUCTURE AND PROPERTIES OF CONVENTIONAL VULCANIZATION IN NATURAL RUBBER

2014 ◽  
Vol 87 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Zhongbiao Man ◽  
Li Deng ◽  
Miao Yang ◽  
Yuehui Chen ◽  
Zhengjie Jin
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Zinc Oxide ◽  
Natural Rubber ◽  
Nano Zno ◽  
X Ray ◽  
Nano Zinc Oxide ◽  
Nano Zinc ◽  
Surface Modified

ABSTRACT In situ surface-modified nano–zinc oxide (ZnO) had been prepared by the sol-gel method. The microscopic structure of the ZnO particles was characterized by X-ray diffraction and transmission electron microscopy. Scanning electron microscopy with energy-dispersed X-ray spectroscopy was used to observe the dispersal of ZnO in conventional vulcanization of natural rubber (NR). Properties such as cure and tensile characteristics as well as heat-resistance oxygen aging properties were researched and compared. The vulcanized structure of vulcanizate was studied by the balance-swelling method and chemical-detecting process. Results demonstrated that the dispersal of in situ surface-modified nano-ZnO in NR vulcanizate was better than that of ordinary ZnO. Compared with the addition of 5 phr of ordinary ZnO in NR, the tensile strength and elongation of NR vulcanizate filled with 2 phr of in situ surface-modified nano-ZnO increased by 0.55% and 10.34%, respectively. Meanwhile, the retention of tensile strength and elongation of vulcanizate increased by 35.85% and 19.36%, respectively.

An Alternative Crosslinking of Epoxidized Natural Rubber with Maleic Anhydride

2017 ◽  
Vol 748 ◽  
pp. 84-90
Author(s):  
Nuttida Srirachya ◽  
Takaomi Kobayashi ◽  
Kanoktip Boonkerd
Keyword(s):  
Tensile Strength ◽  
Maleic Anhydride ◽  
Natural Rubber ◽  
Ir Spectra ◽  
Crosslinking Agent ◽  
Decomposition Temperature ◽  
Epoxidized Natural Rubber ◽  
Rubber Sample ◽  
Ft Ir

This study investigated a novel crosslinking agent for epoxidized natural rubber (ENR). The result showed that it was possible to thermally crosslink ENR with maleic anhydride (MA). No additional catalyst was needed. FT-IR spectra revealed that after heating the ENR mixed with MA, there was the formation of the ester linkages. The crosslinking of ENR via these newly formed linkages was confirmed by the formation of gel once the heated rubber sample was immersed in toluene. The rheographs indicated that the crosslinking can take place at 80 °C and the curing rate and degree of crosslinking were dependent of the MA content. The cured ENR with MA showed higher decomposition temperature and better tensile strength than the uncured one.

Extraction and identification of fillers and pigments from pyrolyzed rubber and tire samples

1996 ◽  
Vol 54 ◽  
pp. 174-175
Author(s):  
P. Sadhukhan ◽  
J. B. Zimmerman
Keyword(s):  
Zinc Oxide ◽  
Electron Microscope ◽  
Carbon Black ◽  
Natural Rubber ◽  
Transmission Electron Microscope ◽  
Rolling Resistance ◽  
Synthetic Polymers ◽  
Nitrogen Atmosphere ◽  
Transmission Electron ◽  
Curing Agents

Rubber stocks, specially tires, are composed of natural rubber and synthetic polymers and also of several compounding ingredients, such as carbon black, silica, zinc oxide etc. These are generally mixed and vulcanized with additional curing agents, mainly organic in nature, to achieve certain “designing properties” including wear, traction, rolling resistance and handling of tires. Considerable importance is, therefore, attached both by the manufacturers and their competitors to be able to extract, identify and characterize various types of fillers and pigments. Several analytical procedures have been in use to extract, preferentially, these fillers and pigments and subsequently identify and characterize them under a transmission electron microscope.Rubber stocks and tire sections are subjected to heat under nitrogen atmosphere to 550°C for one hour and then cooled under nitrogen to remove polymers, leaving behind carbon black, silica and zinc oxide and 650°C to eliminate carbon blacks, leaving only silica and zinc oxide.

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