Wax Blooming and Exposure Cracking

1951 ◽  
Vol 24 (4) ◽  
pp. 1017-1038 ◽  
Author(s):  
L. L. Best ◽  
R. C. W. Moakes
Keyword(s):  
Standard Technique ◽  
Ozone Exposure ◽  
Vulcanized Rubber ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Abstract A brief résumé is given of the types of deterioration which cause cracking and similar forms of deterioration in vulcanized rubber and the possible remedies. A study has been made of the development of wax bloom on rubber and some of the factors which affect this development. The waxes constituting the blooms have been examined, as has the wax in the bulk of the rubber. The protection afforded by these wax blooms against ozone attack on various base mixes with both natural and synthetic rubber has been determined, using a standard technique for the ozone exposure.

Natural and Synthetic Rubber. XIII. The Molecular Weight of Sol Rubber

1934 ◽  
Vol 7 (3) ◽  
pp. 518-520
Author(s):  
Thomas Midgley ◽  
Albert L. Henne ◽  
Alvin F. Shepard ◽  
Mary W. Renoll
Keyword(s):  
Molecular Weight ◽  
Vulcanized Rubber ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Abstract Partially vulcanized rubber has been fractionated into components in which rubber is combined with increasing amounts of sulfur. The analyses of these fractions concur to indicate a molecular weight of about 54,000 for the particular sample of rubber used. Specimens of varied origin can thus have their molecular weight measured by strictly orthodox chemical means.

scholarly journals Alternative of bone china and porcelain as ceramic hand molds for rubber latex glove films formation via dipping process

2020 ◽  
Vol 59 (1) ◽  
pp. 523-537
Author(s):  
Chaturaphat Tharasana ◽  
Aniruj Wongaunjai ◽  
Puwitoo Sornsanee ◽  
Vichasharn Jitprarop ◽  
Nuchnapa Tangboriboon
Keyword(s):  
Thermal Expansion ◽  
Flexural Strength ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Mold Surface ◽  
Rubber Latex ◽  
Latex Glove ◽  
Bone China ◽  
Synthetic Rubber ◽  
Natural And Synthetic

AbstractIn general, the main compositions of porcelain and bone china composed of 54-65%wt silica (SiO2), 23-34% wt alumina (Al2O3) and 0.2-0.7%wt calcium oxide (CaO) suitable for preparation high quality ceramic products such as soft-hard porcelain products for teeth and bones, bioceramics, IC substrate and magneto-optoelectroceramics. The quality of ceramic hand mold is depended on raw material and its properties (pH, ionic strength, solid-liquid surface tension, particle size distribution, specific surface area, porosity, density, microstructure, weight ratio between solid and water, drying time, and firing temperatures). The suitable firing conditions for porcelain and bone china hand-mold preparation were firing at 1270°C for 10 h which resulted in superior working molds for making latex films from natural and synthetic rubber. The obtained fired porcelain hand molds at 1270°C for 10 h provided good chemical durability (10%NaOH, 5%HCl and 10%wtNaCl), low thermal expansion coefficient (5.8570 × 10−6 (°C−1)), good compressive (179.40 MPa) and good flexural strength (86 MPa). While thermal expansion coefficient, compressive and flexural strength of obtained fired bone china hand molds are equal to 6.9230 × 10−6 (°C−1), 128.40 and 73.70 MPa, respectively, good acid-base-salt resistance, a smooth mold surface, and easy hand mold fabrication. Both obtained porcelain and bone china hand molds are a low production cost, making them suitable for natural and synthetic rubber latex glove formation.

Natural and Synthetic Rubber. IV. 4-Methyl-4-Octene by Isoprene Ethylation

1930 ◽  
Vol 3 (3) ◽  
pp. 483-484
Author(s):  
Thomas Midgley ◽  
Albert L. Henne
Keyword(s):  
Double Bond ◽  
Synthetic Rubber ◽  
Double Bond System ◽  
Bond System ◽  
Usual Behavior ◽  
Natural And Synthetic ◽  
Long Chains

Abstract Isoprene has been ethylated; 4-methyl-4-octene was formed exclusively. The structure of this nonene is in agreement with the usual behavior of a conjugated double bond system. This type of addition is further evidence in favor of the hypothesis which regards the polymerization of isoprene to synthetic rubber as the formation of long chains of isoprene units linked together- by ordinary valences in the 1,4-position.

NATURAL AND SYNTHETIC RUBBER. XI. CONSTITUENTS OF THE MILLED RUBBER HYDROCARBON

1932 ◽  
Vol 54 (8) ◽  
pp. 3381-3383 ◽  
Author(s):  
Thomas Midgley ◽  
Albert L. Henne ◽  
Mary W. Renoll
Keyword(s):  
Synthetic Rubber ◽  
Natural And Synthetic

Natural and Synthetic Rubber. XVI. The Structure of Polystyrene

1936 ◽  
Vol 58 (10) ◽  
pp. 1961-1963 ◽  
Author(s):  
Thomas Midgley ◽  
Albert L. Henne ◽  
Henry M. Leicester
Keyword(s):  
Synthetic Rubber ◽  
Natural And Synthetic

The Synthesis of Isocyanate-Modified Novolak Resins for Use in Natural and Synthetic Rubber

1980 ◽  
Vol 53 (2) ◽  
pp. 239-244 ◽  
Author(s):  
N. D. Ghatge ◽  
B. M. Shinde
Keyword(s):  
Tensile Strength ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Abstract Resin-C and Resin-B give higher values for tensile strength, modulus, and hardness than all other resins.

Effect of Storage and Temperature on Flexibility of Natural and Synthetic Rubbers

1948 ◽  
Vol 21 (4) ◽  
pp. 864-876
Author(s):  
John B. Gregory ◽  
Irving Pockel ◽  
John F. Stiff
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Strain Curve ◽  
Polymer Chains ◽  
Stress Strain Curve ◽  
Low Temperature Storage ◽  
Synthetic Rubber ◽  
Loading And Unloading ◽  
Temperature Storage ◽  
Natural And Synthetic

Abstract A new method for measuring the flexibility of rubber has been described. The method consists essentially in determining the stress-strain curve obtained by loading and unloading a loop formed from a one-inch by six-inch strip cut from a test slab. A coefficient of flexibility independent of the thickness of the sample and, in addition, information on per cent resilience were obtained. By the use of the method described, the behavior of various natural and synthetic rubber gas mask facepiece compounds was studied during one month to three months' exposure at various temperatures down to −20° F. Progressive stiffening probably due to crystallization was found for natural rubber, GR-I, and GR-M compounds at low temperatures. No tendency to crystallize was noted for the GR-S compound. Of the crystallizable polymers GR-I was the most resistant, and GR-M the least resistant to stiffening during low temperature storage. It is of course evident that different polymers have inherently different degrees of resistance to low temperatures. Disregarding these inherent differences the work reported indicates that the resistance of elastomer compounds to stiffening during prolonged low temperature storage is favored by the following: 1. Use of interpolymers made from monomer mixtures having a relatively large proportion of each component, thus obtaining mutual intereference with crystallization. 2. Use of a “tight” cure which probably so impedes the movement of the polymer chains as to make crystallization difficult.

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