Natural and Synthetic Rubber. XVII. The Separation of Sol Rubber and Gel Rubber

1937 ◽  
Vol 10 (4) ◽  
pp. 641-642
Author(s):  
Thomas Midgley ◽  
Albert L. Henne
Keyword(s):  
Precipitation Method ◽  
Fractional Precipitation ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Abstract Sol rubber prepared by a single diffusion in ether can be separated into two components by fractional precipitation, whereas sol rubber prepared by a single fractional precipitation completely diffuses in ether, thus indicating the superiority of the fractional precipitation method as a means of preparing sol rubber.

Natural and Synthetic Rubber. XI. Constituents of the Milled Rubber Hydrocarbon

1932 ◽  
Vol 5 (4) ◽  
pp. 543-545
Author(s):  
Thomas Midgley ◽  
Albert L. Henne ◽  
Mary W. Renoll
Keyword(s):  
Continuous Series ◽  
Single Individual ◽  
Fractional Precipitation ◽  
Alcohol Mixture ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Abstract The composition of milled rubber has been investigated by a method based on fractional precipitation from a benzene—alcohol mixture. This has shown that milled rubber is made of a continuous series of undefined components, without a single predominating individual. The same method had previously shown that one single individual constituted more than one-half of unmilled rubber.

Natural and Synthetic Rubber. VII. Fractional Precipitation of Natural Rubber

1931 ◽  
Vol 4 (4) ◽  
pp. 547-551
Author(s):  
Thomas Midgley ◽  
Albert L. Henne ◽  
Mary W. Renoll
Keyword(s):  
Natural Rubber ◽  
Fractional Precipitation ◽  
Synthetic Rubber ◽  
Alcohol Benzene ◽  
Natural And Synthetic

Abstract Temperature—concentration diagrams are given of the systems natural rubber—alcohol—benzene, pure rubber—alcohol—benzene and synthetic rubber—alcohol—benzene. A method based on these diagrams is given for the separation of nitrogen-free rubber hydrocarbon by fractional precipitation of natural rubber from a mixture of alcohol and benzene.

NATURAL AND SYNTHETIC RUBBER. VII. FRACTIONAL PRECIPITATION OF NATURAL RUBBER

1931 ◽  
Vol 53 (7) ◽  
pp. 2733-2737 ◽  
Author(s):  
Thomas. Midgley ◽  
Albert L. Henne ◽  
Mary W. Renoll
Keyword(s):  
Natural Rubber ◽  
Fractional Precipitation ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Natural and Synthetic Rubber. X. Constituents of the Rubber Hydrocarbon

1932 ◽  
Vol 5 (4) ◽  
pp. 537-542
Author(s):  
Thomas Midgley ◽  
Albert L. Henne ◽  
Mary W. Renoll
Keyword(s):  
Physical Constant ◽  
Single Component ◽  
Fractional Precipitation ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Abstract 1. Fractional precipitation has been used to determine and isolate the constituents of the rubber hydrocarbon. 2. A “standard precipitation point” has been devised and its use advanced as a physical constant of rubber. 3. The presence of a single component, amounting to more than 50% and characterized by a standard precipitation point of 35°, has been demonstrated. 4. The presence of highly soluble portions, of indeterminate s. p. p., has been shown.

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

The Chromatography of Rubber Solutions

1939 ◽  
Vol 12 (4) ◽  
pp. 762-773 ◽  
Author(s):  
Giampietro Cajelli
Keyword(s):  
Elastic Properties ◽  
Potassium Hydroxide ◽  
The Other ◽  
Precipitation Method ◽  
Insoluble Residue ◽  
Fractional Precipitation ◽  
Micellar Structure ◽  
X Ray ◽  
Colored Product ◽  
Considerable Doubt

Abstract In the opinion of Pummerer, there is considerable doubt about the homogeneity of the fractions obtained by fractional precipitation of rubber from dilute benzene solutions, both with respect to the size of the molecules and to the state of aggregation. Based on the results of x-ray measurements of fibrous substances, to which type stretched rubber belongs, Meyer and Mark have advanced the hypothesis of the existence of chains of primary valences and of a micellar structure. PURIFICATION OF RUBBER There are four important and at the same time essentially different ways of carrying out the difficult process of purifying rubber. According to Harries, acetone extraction gives a colored product and leads to profound changes in the elastic properties. Staudinger adopted the method described by Wildmann in 1911, which involves the use of a mixture of acetone and chloroform. On the other hand, Pummerer and Koch used the method of fractional precipitation; the rubber after severe mastication was extracted with acetone, was dissolved in benzene, the liquid was allowed to stand for several weeks, the solution was decanted from the insoluble residue and was fractionally precipitated by alcohol and acetone. More recently this same method has been perfected by Pummerer and Meidel, and by this means a fraction of crystallized rubber was isolated from the mother liquors of the fractional precipitation. Finally Pummerer and Koch have purified rubber by treatment with an alkali, combining the precipitation method with the use of a solution of potassium hydroxide in methanol. Later this method was modified by Pummerer and Pahl. The use of latex in place of crude rubber is the most important development in obtaining a satisfactory product. De Vries and Beumée-Nieuwland have described in detail some results obtained with fresh latex. The total-rubber obtained by the methods just described contains, according to the quality and the age of the sample of latex, from 0.1 to 0.4 per cent of nitrogen which cannot be removed by washing, even when this is exhaustive.

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