Tetramethylthiuram Disulfide Vulcanization of Extracted Rubber. IV. Behavior of Rubber as an Acid

1951 ◽  
Vol 24 (2) ◽  
pp. 269-275
Author(s):  
David Craig ◽  
A. E. Juve ◽  
W. L. Davidson
Keyword(s):  
Zinc Oxide ◽  
Organic Acids ◽  
Palmitic Acid ◽  
Present Series ◽  
Tetramethylthiuram Disulfide ◽  
Metallic Oxides ◽  
Retarding Effect ◽  
Acids And Bases

Abstract The retarding effect of organic acids on vulcanization as well as the activating effect of certain acids on certain accelerators is well recognized. The activating and accelerating effects of bases and metallic oxides is also well recognized. In this connection, the mild activating effect of palmitic acid on vulcanization with TMTD in the presence of zinc oxide was described in the first paper of the present series. With the behavior of acids and bases during vulcanization as a background, the study of rubber itself as an acid has been undertaken. This paper sets forth a description of two reactions investigated during the study. These are the reaction of rubber with zinc palmitate and of TMTD with acids.

Tetramethylthiuram Disulfide Vulcanization of Extracted Rubber. I. Introduction and Compounding

1951 ◽  
Vol 24 (2) ◽  
pp. 254-262 ◽  
Author(s):  
David Craig ◽  
A. E. Juve ◽  
W. L. Davidson
Keyword(s):  
Zinc Oxide ◽  
Palmitic Acid ◽  
Zinc Sulfide ◽  
Main Product ◽  
Tetramethylthiuram Disulfide ◽  
Effective Activator

Abstract (1) Large dosages of TMTM inhibit TMTD vulcanization or vulcanization with sulfur. (2) The desirability of up to about 1.5 phr zinc oxide for TMTD vulcanization was confirmed. If an unusually large amount of TMTD (10 phr) is used, a well vulcanized stock may be obtained without zinc activation. (3) Palmitic acid displays only a mild activating effect on TMTD vulcanization. (4) Zinc dimethyldithiocarbamate, a main product of TMTD vulcanization, is not an activator for a TMTD-zinc oxide recipe. (5) Dimethylammonium dimethyldithiocarbamate does not activate TMTD-zinc oxide formulations. (6) Zinc sulfide is an effective activator for TMTD vulcanization.

pK a Prediction for Organic Acids and Bases

1981 ◽  
Author(s):  
D. D. Perrin ◽  
Boyd Dempsey ◽  
E. P. Serjeant
Keyword(s):  
Organic Acids ◽  
Acids And Bases

Effect of Sulfur and Dicumyl Peroxide on Vulcanization of Natural Rubber with Tetramethylthiuram Disulfide and Zinc Oxide

1970 ◽  
Vol 43 (6) ◽  
pp. 1294-1310 ◽  
Author(s):  
S. P. Manik ◽  
S. Banerjee
Keyword(s):  
Zinc Oxide ◽  
Stearic Acid ◽  
Natural Rubber ◽  
Reaction Mechanisms ◽  
Elemental Sulfur ◽  
Initial Rate ◽  
Dicumyl Peroxide ◽  
Tetramethylthiuram Disulfide ◽  
Sulfur Vulcanization ◽  
Salient Features

Abstract The salient features of both non-elemental sulfur vulcanization by TMTD and elemental sulfur vulcanization promoted by TMTD both in presence and absence of ZnO and stearic acid have been studied. TMTD increases the rate of DCP decomposition and lowers the crosslinking maxima due to DCP depending on its concentration. However, with higher amounts of TMTD the initial rate of crosslinking is increased with the increased amount of TMTD, while crosslinking maxima are still lowered due to reversion. ZnO or ZnO-stearic acid, however, seems to alter the entire course of the reaction. Both the crosslink formation and TMTD decomposition are much higher in presence of ZnO or ZnO-stearic acid, but stearic acid seems to have no effect. The reaction mechanisms for TMTD accelerated sulfuration in absence and presence of ZnO have also been studied.

A Titrimetric Method for Determining Organic Acids and Bases in Urine

1966 ◽  
Vol 12 (12) ◽  
pp. 830-836 ◽  
Author(s):  
Gussie Goldberg ◽  
Wellington Paul ◽  
Harvey Gonick
Keyword(s):  
Organic Acids ◽  
Alkaline Medium ◽  
Titrimetric Method ◽  
Single Procedure ◽  
Acids And Bases

Abstract Organic acids and bases can be determined in a single procedure by first precipitating protein and removing carbonate with concentrated HCI, then adding Ca(OH)2 to precipitate phosphate and create an alkaline medium, removing ammonia by heat and suction, then finally titrating from pH 10.5 to 2.7 with dilute HCI.

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