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Titolo:
Free-volume microprobe study of iodine diffusion in polymers
Autore:
Ramani, R; Ranganathaiah, C;
Indirizzi:
Armed Forces Med Coll, Dept Pathol, Pune 411040, Maharashtra, India Armed Forces Med Coll Pune Maharashtra India 411040 0, Maharashtra, India Univ Mysore, Dept Studies Phys, Mysore 570006, Karnataka, India Univ Mysore Mysore Karnataka India 570006 Mysore 570006, Karnataka, India
Titolo Testata:
POLYMER INTERNATIONAL
fascicolo: 2, volume: 50, anno: 2001,
pagine: 237 - 248
SICI:
0959-8103(200102)50:2<237:FMSOID>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
POSITRON-ANNIHILATION; AMORPHOUS POLYMERS; SOLVENT DIFFUSION; ORGANIC LIQUIDS; LARGE MOLECULES; WATER SORPTION; POLYCARBONATE; TRANSPORT; POLY(ETHYLENE-TEREPHTHALATE); POLYURETHANE;
Keywords:
free-volume; positron lifetime; iodine diffusion; acrylonitrile-butadiene-styrene; poly(ethylene terephthalate); polycarbonate;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
63
Recensione:
Indirizzi per estratti:
Indirizzo: Ranganathaiah, C Armed Forces Med Coll, Dept Pathol, Pune 411040, Maharashtra, India Armed Forces Med Coll Pune Maharashtra India 411040 ndia
Citazione:
R. Ramani e C. Ranganathaiah, "Free-volume microprobe study of iodine diffusion in polymers", POLYM INT, 50(2), 2001, pp. 237-248

Abstract

The effect of iodine sorption on the free-volume of three polymers, namely, acrylonitrile-butadiene-styrene, poly(ethylene terephthalate) and polycarbonate have been investigated by the positron annihilation Lifetime technique. Diffusion coefficients have been evaluated from the sorption curves using Crank's solution for Fick's second law of diffusion. The positron results are explained in terms of iodine filling the free-volume holes, swelling and conformational changes. It has also been found that the diffusion process in acrylonitrile-butadiene-styrene and poly(ethylene terephthalate) deviates from Fick's law of diffusion whereas in polycarbonate, the diffusion process obeys Fick's law. Further, for polymers in which diffusion deviates from Fick's law, the sorption process has been separated into diffusion-controlled (Fickian) and relaxation-controlled (non-Fickian) parts using the dual-mode sorption model. Interestingly, the present results show that the polymers which deviate from Fickian diffusion also deviate from Fujita's free-volume theory of diffusion and vice versa. The positron results also indicate that sorbed iodine in the polymer acts as an inhibitor of orthopositronium. (C) 2001 Society of Chemical Industry.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/04/20 alle ore 22:45:06