Vulcanization of Synthetic Rubbers by the Peachey Process

1948 ◽  
Vol 21 (3) ◽  
pp. 701-710
Author(s):  
Norman Bekkedahl ◽  
Fred A. Quinn ◽  
Elmer W. Zimmerman
Keyword(s):  
Hydrogen Sulfide ◽  
Sulfur Dioxide ◽  
Natural Rubber ◽  
Styrene Copolymers

Abstract The Peachey process, which vulcanizes natural rubber by subjecting it alternately to sulfur dioxide and hydrogen sulfide gases, has been found to vulcanize the more common synthetic rubbers. The polymer studies were natural rubber, GR-S; GR-M, GR-I, GR-A, Hycar OR-15, Hycar OR-25, Hycar OS-10, Hycar OS-20, and Hycar OS-30. Good cures were obtained with all of the polymers except GR-M. None of the synthetic rubbers cured any faster than natural rubber. The nitrile and the styrene copolymers of butadiene cured at about the same rate or somewhat slower. GR-I required roughly 50 times as long as natural rubber for an equivalent cure, and GR-M required even longer.

Studies of the Vulcanization of Rubber. X. The Vulcanization of Natural Rubber with a Mixture of Sulfur Dioxide and Hydrogen Sulfide

1953 ◽  
Vol 26 (3) ◽  
pp. 559-566 ◽  
Author(s):  
B. A. Dogadkin ◽  
F. Keifetz
Keyword(s):  
Tensile Strength ◽  
Hydrogen Sulfide ◽  
Sulfur Dioxide ◽  
Natural Rubber ◽  
Sulfur Content ◽  
Spatial Network ◽  
Smooth Curves ◽  
Multiple Cycles

Abstract 1. The dynamics of the changes of the properties of rubber during vulcanization by a mixture of sulfur dioxide and hydrogen sulfide, in distinction from conventional vulcanization by sulfur, is expressed by smooth curves. No vulcanization optimum is observed. 2. With multiple cycles of vulcanization, the increase of bound sulfur content above 3 per cent results in a decrease of tensile strength. 3. Changes of tensile strength of the vulcanizate dependent on changes of sulfur content are attributable to the influence of the density of the spatial network on the orientation processes during deformation.

Vulcanization of GR-S by the Peachey Process

1947 ◽  
Vol 20 (1) ◽  
pp. 182-183
Author(s):  
Archibald T. McPherson
Keyword(s):  
Hydrogen Sulfide ◽  
Sulfur Dioxide ◽  
Natural Rubber ◽  
Glass Tube ◽  
The Other ◽  
Curing Process ◽  
Sulfide Sulfur ◽  
Simple Apparatus ◽  
Synthetic Rubber

Abstract It has been found possible to vulcanize GR-S synthetic rubber by subjecting it alternately to hydrogen sulfide and sulfur dioxide gases. This method for curing, known as the Peachey process, was used for natural rubber as long ago as 1921. A simple apparatus was constructed, in which strips of thinly milled rubber were placed on a screen inside a glass tube. One end of this tube was attached to valves connecting it to tanks of hydrogen sulfide, sulfur dioxide, and air, respectively. The other end of the tube led to a series of traps containing solutions which absorbed or destroyed the gases. For each test performed, natural rubber samples were placed inside the tube along with the GR-S samples for comparison. Each strip was weighed before it was inserted in the apparatus. Hydrogen sulfide was first slowly passed over the samples for a period of five minutes. Then air was blown through for a few seconds—just long enough to free the surroundings from the sulfide gas, but not long enough for the gas to be lost from solution in the rubber. Sulfur dioxide gas was next admitted and allowed to pass over the samples for five minutes. A subsequent short sweep of air through the tube completed one cycle of the curing process.

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.

Cis-trans Isomerization in Polyisoprenes. Part VII. Double Bond Movement During Isomerization of Natural Rubber and Related Olefins

1967 ◽  
Vol 40 (3) ◽  
pp. 921-927
Author(s):  
J. I. Cunneen ◽  
G. M. C. Higgins ◽  
R. A. Wilkes
Keyword(s):  
Double Bond ◽  
Sulfur Dioxide ◽  
Natural Rubber ◽  
Structural Modification ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Trans Isomerization ◽  
Acidic Compounds

Abstract When trans-3-methyl-2-pentene or trans-3-methyl-3-hexene is treated with butadiene sulfone, thiolbenzoic acid, and dibenzoyl disulfide under anaerobic conditions, the olefin undergoes only cis-trans isomerization. However, similar reactions in the presence of oxygen or peroxides also cause changes in the position of the double bond. The latter structural modification is probably caused by acidic compounds formed by oxidation of the isomerization reagents. With natural rubber the nonrubber substances prevent movement of the double bond, and cis-trans isomerization is the sole change, even when the reaction with sulfur dioxide is carried out under aerobic conditions.

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