Crystallinity Effect on the Gas Transport in Semicrystalline Coextruded Films Based on Linear Low Density Polyethylene
Por:
Compañ V., Del Castillo L.F., Hernández S.I., Lopez-Gonzalez, MM, Riande E.
Publicada:
15 mar 2010
Resumen:
This article describes the diffusion and permeability of oxygen, carbon dioxide, methane, ethane, ethylene, propane, and propylene in 1-octene based polyethylene of densities 0.94, 0.92, 0.904, and 0.87. The isotherms obtained in the time-lag experimental device display a diffusion coefficient and permeability behavior similar to that of glassy polymers. We apply the dual model to semicrystalline polymers assuming that Henry's sites are related to the amorphous phase, which decreases when the crystallinity percentage increases. Whereas the interphase of the polymeric matrix and the crystalline phase prevails and acts as Langmuir sites. Their effect is to increase both, the tortuosity of diffusion trajectories and the chain immobilization. We now explain this effect using thermodynamic considerations. In fact, the tortuosity is related to the change in activation entropy, and the chain immobilization to the cohesive energy of the polymeric matrix. In those terms, the diffusion coefficie
Filiaciones:
Compañ V.:
Departamento de Termodinámica Aplicada, ETSII, Universidad Politécnica de Valencia, Campus de Vera s/n, 46022-Valencia, Spain
Del Castillo L.F.:
Univ Nacl Autonoma Mexico, Dept Polimeros, Inst Invest Mat, Mexico City 04510, DF, Mexico
Hernández S.I.:
Univ Nacl Autonoma Mexico, Dept Polimeros, Inst Invest Mat, Mexico City 04510, DF, Mexico
Riande E.:
Instituto de Ciencia y Tecnología de Polímeros (CSIC), 28006 Madrid, Spain
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