Diffusion of additives and plasticizers in poly(vinyl chloride)—I. The 1:2 double disc method for obtaining the diffusion coefficient of additives in polymers

✍ Scribed by G.S. Park; Tran Van Hoang

• Publisher: Elsevier Science
• Year: 1979
• Tongue: English
• Weight: 411 KB
• Volume: 15
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(79)90181-2

✦ Synopsis

Abstrac~A simple expression has been obtained for the change with time, t, of the difference, (Ao -Ai), between the radioactivity of the two faces of a disc of material made by joining a disc containing radioactive diffusant to a similar disc containing no radioactive material. It is shown, for the special case where one of the discs is twice as thick as the other, that linear plots of ln(Ao -Ai) vs t should be obtained almost from the very beginning of the experiment and that the slope of these plots should be -n2D/l~, where l is the total thickness of the double disc. The diffusion coefficients for dibutyl tin dilaurate in a variety of plasticized poly(vinyl chloride)s over a range of temperatures have been obtained from plots of this kind; the validity of this simple method has been confirmed by computer calculations.