ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The crosslinking efficiencies of several curing agents have been determined from swelling measurements. The results indicate that dicumyl peroxide is a quantitative crosslinking agent for natural rubber, as was previously found to be true of dimethyloctadiene. As one molecule of dicumyl peroxide is able to form one crosslink, 3.2 to 4.0 molecules of tetramethylthiuram disulfide or 9-10 sulfur atoms in a sulfur-sulfeneamide system are needed for the same purpose. A comparison is made between the number of chemically introduced crosslinks and a corresponding value obtained from swelling measurements with the help of the Flory-Rehner equation. It was found that a filler can effect the properties of a vulcanizate through a filler-curing agent interaction as well as through a filler-rubber interaction. When a filler-curing agent interaction takes place, a certain amount of curing agent or accelerator becomes unavailable for cure. This lowers the number of crosslinks introduced by the curing agent. If the filler-curing agent interaction is insignificant and can be neglected, the swelling value Q for a filled stock can be related to that of an unfilled, analogous gum vulcanizate, Qgum, by the simple equation Q = kQgum; k is a function of the nature and amount of the filler and the elastomer, but is independent of the curing agent.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1961.1205015404
Permalink
