Interactions between water and EVOH food packaging films / Interacciones entre el agua y películas de EVOH para el envasado de alimentos

Abstract

The transport of water in four EVOH copolymers commonly used in high barrier food packages was characterized through permeation (continuous flow) and gravimetric experiments at different rela tive humidities and 23 ± 2°C. Water sorption isotherms were fitted with the D'Arcy and Watts' equa tion. From these data, the value of the solubility coefficient (S, as defined by Henry's law) was deter mined and was found constant within a 0.2-0.75 water activity (a _w) range. Water uptake at the same a _w increased as the EVOH ethylene content decreased. The permeability coefficient (P) for water through EVOH was determined as a function of water activity. The permeability was constant within the range of 0.3-0.75 a _w and decreased with EVOH ethylene content. At high relative humidities (a _w > 0.75) the value of permeability increased by up to two orders of magnitude. In this range, the higher the ethylene content the lesser the value of P.

Keywords

water EVOH permeation sorption

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References

Aucejo S. , Pozo M.J. and Gavara R. (1998). Effect of water presence on the sorption of organic compounds in ethylene-vinyl alcohol. Journal of Applied Polymer Science 70: 711-716.

Aucejo S. , Marco S. and Gavara R. (1999). Water effect on the morphology of EVOH copolymers . Journal of Applied Polymer Science 74: 1201-1206.

Barrer R.M. (1984). Diffusivities in glassy polymers for the dual sorption model. Journal of Membrane Science 18: 25-35.

Catalá R. and Gavara R. (1997). Alternative high barrier polymers for food packaging . Food Science and Technology International 2: 281-291.

D'Arcy R.L. and Watt I.C. (1970). Analysis of sorption isotherms of non-homogeneous sorbents. Transactions of the Faraday Society 66: 1236-1245.

Farrell C.J. , Tsai B.C. and Wachtel J.A. (1986). Multi-layer polymeric structure having a moisture sensitive polymeric layer. European patent 81-300818.

Gavara R. , Catalá R. , Aucejo S. , Cabedo D. and Hernández R.J. (1996). Solubility of alcohols in ethylene-vinyl alcohol copolymers by inverse gas chromatography. Journal of Polymer Science: Polymer Physics edition 34: 1907-1915.

Hernández R.J. and Gavara R. (1994). Sorption and transport of water in Nylon-6 films . Journal of Polymer Science: Polymer Physics edition 32: 2367-2374.

Hernandez-Muñoz P. , Gavara R. and Hernández R.J. (1999). Evaluation of solubility and diffusion coefficients in polymer film-vapor systems by sorption. Journal of Membrane Science 154: 195-204.

10.

Johansson F. and Leufven A. (1994). Food packaging polymer films as aroma vapor barriers at different relative humidities. Journal of Food Science 59: 1328-1331.

11.

Lee S.Y. and Kim S.C. (1998). Effect of compatibilizer on the crystallization, rheological, and tensile properties of LDPE / EVOH blends. Journal of Applied Polymer Science 68: 1245-1256.

12.

Liu K.J. , Giacin J.R. and Hernández R.J. (1988). The effect of relative humidity on the permeability of toluene vapour through a multi-layer coextruded film containing hydrophilic layers. Packaging Technology and Science 1: 57-65.

13.

Luque P. , Gavara R. and Heredia A. (1996). A study of the hydration process of isolated cuticular membranes. New Phytologist 129: 283-288.

14.

Nobile M.A. del , Laurienzo P. , Malinconico M. , Mensitieri G. and Nicolais L. (1997). New functionalized ethylene/vinyl alcohol co-polymers: synthesis and water vapour transport properties. Packaging Technology and Science 10: 95-108.

15.

Perry R.N. and Green D.W. (eds) (1984). Perry's Chemical Engineers' Handbook. 6th edn. New York: McGraw-Hill. pp. 16-12.

16.

Vertucci C.W. and Leopold A.C. (1987). Water binding in legume seeds. Plant Physiology 85: 224-231.

17.

Weast R.C. (ed.) (1987). CRC Handbook of Chemistry and Physics. 68th edn. Boca Raton, FL: CRC Press. p. E-42.