Effect of molecular structure on diffusion of organic solvents in rubbers

✍ Scribed by C.J. Guo; D. De Kee; B. Harrison

• Book ID: 103007119
• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 869 KB
• Volume: 47
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(92)85001-r

✦ Synopsis

Diffusion coefficients at zero solvent concentration (Dy,) of methylene chloride, chloroform, carbon tetrachloride, benzene, p-xylene and o-xylene in natural rubber and silicone rubber were determined using a desorption technique at temperatures ranging from 293.2 to 333.2 K. The rate of diffusion shows a clear deFndence on solvent structure. We observed that the effect of molecular size and shape on diffusion is characterized by an effective molecular volume, V,,,. instead of the liquid volume at 0 K. V,,, is calculated from an effective molecular diameter which is obtained by applying a weighting function over the three dimensions of the solvent molecule. The use of F',,, links the free-volume parameters linearly to solvent molecular geometry. This allows for the prediction as well as the correlation of the diffusion coefficients of a solvent-polymer system using the properties of the pure polymer and the solvent.