Polymer structure and the compensation effect of the diffusion pre-exponential factor and activation energy of a permeating solute

• Tipo: Artigo em Revista Científica Internacional
• Data: 2007

Autores

Zheng, JM (Autor) Outra; Qiu, J (Autor) Outra; Luis Madeira (Autor) FEUP; Adélio Mendes (Autor) FEUP

Revista

Título: Journal of Physical Chemistry B

Vol. 111

Páginas: 2828-2835

ISSN: 1520-6106

Editora: American Chemical Society

Indexação

ISI Web of Knowledge - 8 Citações

ISI Web of Science

Scopus - 9 Citações

Classificação Científica

FOS: Ciências da engenharia e tecnologias

CORDIS: Ciências Tecnológicas > Engenharia > Engenharia química

Outras Informações

ID Authenticus: P-004-B4T

DOI: 10.1021/jp067661o

Abstract (EN): In the present work, the relation between the pre-exponential factor and the apparent activation energy of diffusion, ln D-0 = alpha + beta E-D, so-called compensation effect, is re-examined and critically discussed for diffusion of gases in rubbery and glassy polymers. In principle, the above equation could be derived from the enthalpy-entropy compensation in the framework of the transition state theory. However, one should consider the influence of the jump length term contained in the pre-exponential factor, which may be affected by permeating species and polymer properties. We found that parameter alpha depends on penetrant size and polymer properties, such as local chain mobility and free volume. This can be interpreted by the fact that the jump length is affected by both penetrant and polymer properties. Finally, methods for estimating the jump length are discussed.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 8