Diffusion in amorphous polymers

摘要: Diffusion and solubility coefficients are presented for He, Ne, Ar, N2 in three ethylene-propylene copolymers, two styrene-butadiene copolymerg a cis-poly-butadiene five temperature levels the range 0–50°C. The data were obtained by using slightly modified Dow Gas Transmission Cell analyzed new time-lag technique which properly accounts increase pressure on downstream side of cell. Activation energies calculated twenty-four diffusion systems correlated with polymer intermolecular forces gas molecule sizes ii cell theory amorphous polymers employs potential energy depth parameter, ϵ*, p*, number degrees freedom per structural unit (center), 3Cm, centers cell, n. first parameters evaluated from thermodynamic data, while n was data. It is believed that an indication backbone carbon atoms active segmental motion. values here (5–9) agree well existing estimated viscous flow A correlation shown linear free relationship discussed.