Air Permeability of Elastomers by Diffusion Tests

1954 ◽  
Vol 27 (4) ◽  
pp. 996-1004 ◽  
Author(s):  
M. Czuha
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Large Range ◽  
Air Permeability ◽  
Solution Viscosity ◽  
Dilute Solution ◽  
Slight Effect ◽  
Structural Modifications ◽  
Styrene Copolymers ◽  
Mooney Viscosity

Abstract The permeability of various tread compounds to air was measured in a modified Warburg diffusion apparatus. Measurements were made at 30° C, with air applied at 48 psi. pressure, on molded disks approximately 0.025 inch thick and an area of 12.57 sq. in. The tests were reproducible within 4 per cent on control specimens. The compounds investigated showed permeabilities intermediate between the low values for Butyl and the high values for natural rubber. The permeability decreased with increasing combined styrene contents and with a decrease of temperature of polymerization for polybutadiene and low-styrene copolymers. It was unaffected by variation over a large range in polymer Mooney viscosity, gel content, and dilute-solution viscosity. A slight and almost linear decrease of permeability was found with increases in time of cure and carbon black loading for the stocks. In terms of the 300 per cent modulus, an increase of 100 psi. was accompanied by a 2 per cent decrease in permeability. Processing oil in the polymer had only a slight effect on permeability, when compared to the effects of compositional and structural modifications. Alfin and sodium, 75/25 BD/S, copolymers showed the lowest air permeability of the tread type of compounds that were studied.

Flow Patterns in Elastomers and Their Carbon Black Compounds during Extrusion through Dies

1985 ◽  
Vol 58 (4) ◽  
pp. 815-829 ◽  
Author(s):  
Chin-Yuan Ma ◽  
James L. White ◽  
Frederick C. Weissert ◽  
Avraam I. Isayev ◽  
Nobuyuki Nakajima ◽  
...  
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Flow Patterns ◽  
Entrance Region ◽  
Evidence Based ◽  
Streamline Flow ◽  
Basic Study ◽  
Entrance Angle ◽  
Styrene Copolymers ◽  
Butadiene Styrene

Abstract A basic study of flow patterns in elastomers in the entrance region of a die has been carried out for various gum elastomers including emulsion and solution butadiene—styrene copolymers, polybutadiene, and natural rubber. All exhibit streamline flow into the entrance with the exception of a cold mastication degraded natural rubber which gave evidence of vortices in corners. A study of a die with a sharp diverging region showed dead spaces for all the elastomers. Carbon black compounds all exhibited converging streamline flow in a 180° entrance angle die and stagnant regions in the sharply diverging die. Evidence based on marker motions has been presented for slip in elastomer compounds in the entrance region.

Transient Electromechanical Behavior of Carbon-Black-Filled Rubber

1987 ◽  
Vol 60 (4) ◽  
pp. 705-715 ◽  
Author(s):  
Donald R. Parris ◽  
Larry C. Burton ◽  
Muliawati G. Siswanto
Keyword(s):  
Dielectric Constant ◽  
Steady State ◽  
Carbon Black ◽  
Natural Rubber ◽  
Transient Response ◽  
Strong Correlation ◽  
Large Range ◽  
Qualitative Model ◽  
Electrical Measurements ◽  
Filled Rubber

Abstract This work has shown the sensitivity and uniqueness of conductivity and dielectric constant transient response to compressional stress for natural rubber filled with specific types of carbon black. The strong correlation between conductivity and capacitance (both steady-state magnitudes and transients) is attributed to the polymer itself. A qualitative model for these effects is based on changes of conductive and resistive microelements due to fracture of the carbon black matrix. Transient electrical measurements of this type should be applicable to carbon-black- (or metal-) filled dielectrics over a large range of resistivity.

Influence of Pyrolytic Carbon Black Prepared from Waste Tires on Mechanical Properties of Natural Rubber Vulcanizates

2017 ◽  
Vol 751 ◽  
pp. 332-336 ◽  
Author(s):  
Sarawut Prasertsri ◽  
Sansanee Srichan
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Natural Rubber ◽  
Pyrolytic Carbon ◽  
Filler Loading ◽  
Elongation At Break ◽  
Cure Time ◽  
Mooney Viscosity ◽  
Heat Build Up ◽  
Natural Rubber Vulcanizates

This research aimed to investigate the possibility of pyrolytic carbon black (PCB) used as filler in natural rubber (NR) and its effect on Mooney viscosity, cure characteristics and mechanical properties compared with commercial carbon black (N774). The results revealed that Mooney viscosity, stiffness and heat build-up tended to increase with increasing both PCB and N774 loading, whereas elongation at break decreased. However, the maximum tensile and tear strengths appeared at the optimum filler loading for both PCB and N774. At similar filler content, PCB-filled NR compounds have higher cure time, heat build-up and thermal resistance. Nevertheless, they exhibited lower Mooney viscosity and mechanical properties compared to N774-filled NR. Finally, it can be concluded that PCB could be utilized as filler in NR compound to act as semi-reinforcing filler and was classified as a filler to reduce costs.

Carbon Nanotubes in Tyre Rubbers. Part 1: The Effect of Carbon Nanotubes on the Properties of Breaker Rubber

2017 ◽  
Vol 44 (3) ◽  
pp. 13-18
Author(s):  
A.R. Mukhtarov ◽  
A.M. Mokhnatkin ◽  
V.P. Dorozhkin ◽  
E.G. Mokhnatkina ◽  
V.E. Muradyan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Wear Resistance ◽  
Ir Spectroscopy ◽  
Carbon Black ◽  
Natural Rubber ◽  
Single Wall Carbon Nanotubes ◽  
Cohesion Strength ◽  
Metal Cord ◽  
Mooney Viscosity

The processing and mechanical properties of green and vulcanised breaker rubbers based on natural rubbers containing single-wall carbon nanotubes (SCNTs) were studied. SCNTs were treated and introduced into a rubber mix in a composite containing carbon black (88.24%), SCNTs (9.8%), and SKI-3 polyisoprene rubber in solution (1.96%). The presence of –COOH groups on the surface of SCNTs after treatment was confirmed by IR spectroscopy. Increase in the content of SCNTs in the breaker rubber mix to 0.15 or 0.2% leads to an increase in cohesion strength up to 1.6-fold; the Mooney viscosity also increases, and there is an improvement in the vulcanisation properties. Changes in the Payne effect of rubbers containing SCNTs indicate an improvement in the interaction between the carbon black particles. Small amounts of SCNTs ensure a reduction in tg δ at 60°C, and increases in tear strength and in adhesion to metal cord. However, wear resistance deteriorates. The possibility of replacing 30 parts natural rubber with SKI-3 in the presence of SCNTs is shown.

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.

Rubber Fracture Characterization Using J-Integral

1988 ◽  
Vol 16 (1) ◽  
pp. 44-60 ◽  
Author(s):  
C. L. Chow ◽  
J. Wang ◽  
P. N. Tse
Keyword(s):  
Crack Initiation ◽  
Carbon Black ◽  
Natural Rubber ◽  
Fracture Parameter ◽  
J Integral ◽  
Specimen Length ◽  
Fracture Characterization ◽  
Premature Failure ◽  
Testing Procedures ◽  
Material Evaluation

Abstract The use of the J-integral to investigate fracture characterization in a carbon black reinforced natural rubber is described. Three applications to crack initiation are included: two based on the use of a hypothetical zero specimen length and one on conventional testing procedures for metals. While the validity of the zero-length methods is questionable, the conventional method yielded a consistent Jc value of 1.01 N/mm for a typical tire compound. This value was obtained from 24 combinations of varying specimen geometries and pre-crack lengths. The J-integral is revealed as a valid fracture parameter that is applicable not only for material evaluation but also for designing tire structures to resist premature failure. These conclusions disagree with those from an earlier investigation, so the causes for the discrepancies are examined and discussed.

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