Polyisoprene self-diffusion

Fig. 4. Self-diffusion in cis-polyisoprene melts as function of molecular weight, at five temperatures. Curves are single fit of Eq. (8) with Eq. (9) to all data. (Ref.41>, with permission).

Fleisher G, Appel M (1995) Chain length and temperature dependence of the self-diffusion of polyisoprene and polybutadiene in the melt. Macromolecules 28(21) 7281-7283 Flory PJ (1953) Principles of polymer chemistry. Cornell Univ. Press, New York Flory PJ (1969) Statistics of chain molecules. Interscience, New York... 

The self-diffusion of benzene in PIB [36], cyclohexane in BR [37] and toluene in PIB [38-40] has been investigated by PFG NMR. In addition more recently Schlick and co-workers [41] have measured the self-diffusion of benzene and cyclohexane mixtures in polyisoprene. In the first reported study of this kind, Boss and co-workers [36] measured the self-diffusion coefficients of benzene in polyisoprene at 70.4 °C. The increase in Dself with increasing solvent volume fraction could be described by the Fujita-Doolittle theory which states that the rate of self-diffusion scales with the free volume which in turn increases linearly with temperature. At higher solvent volume fractions the rate of selfdiffusion deviates from the Fujita-Doolittle theory, as the entanglement density decreased below the critical value. 

Bueche et al. (1952) derived that the coefficient for self-diffusion of poly(n-butyl acrylate) is inversely proportional to the bulk viscosity of this polymer. Also in the natural rubber (polyisoprene) diffusion system a clear connection appears to exist between diffusion coefficient and bulk viscosity. In general the following expression may be used as a good approximation ... 

Harmandaris, V.A., Doxastakis, M., Mavrantzas, V.G., and Theodorou, D.N., 2002, Detailed molecular dynamics simulation of the self-diffusion of n-alkane and cis-1,4 polyisoprene oligomer melts , J. Chem. Phys. 116,436. 

Figure 33.12 Self-diffusion coefficient D of seven different types of polymers (polystyrene, poly(ethyleneoxide), polyisoprene, polybutadiene, poly(dimethylsiloxane), poly(ethylene oxide), poly(methylstyrene)) versus molecular weight shows that D oc N - which differs somewhat from the N...

E. von Meerwall, D. H. Tomich, N. Hadjichristis, and L. J. Fetters. Phenomenology of self-diffusion in star-branched polyisoprenes in solution. Macromolecules, 15 (1982), 1157-1163. 

C. Xuexin, X. Zhongde, E. von Meerwall, et al. Self-diffusion of linear and 4- and 18-armed star polyisoprenes in tetrachloromethane solution. Macromolecules, 17 (1984), 1343-1348. 

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