Viscoelastic Properties of Poly(methyl methacrylates) Prepared by Anionic Polymerization

Conformational relaxation of single polymer chains confined in a two-dimensional plane studied by scanning near-field optical microscopy

“…33 In this model, the polymer chain is constrained in a virtual tube composed of the entanglement network of neighboring chains, and the random motion occurs in the tube. The diffusion obeys Fick's law for a time that is longer than the reptation time t. In our system, the annealing time is far shorter than the reptation time, which was estimated to be 6Â10 3 h, 34 indicating that the observed motion is not characterized by reptational diffusion. Furthermore, the diffusion coefficient of the large molecular weight PMMA used in this experiment was estimated to be 10 À17 to 10 À18 at 170 1C, 27,34,35 whereas the apparent diffusion coefficient until 48 h in Figure 8 was 1Â10 À16 cm 2 s À1 .…”

“…The diffusion obeys Fick's law for a time that is longer than the reptation time t. In our system, the annealing time is far shorter than the reptation time, which was estimated to be 6Â10 3 h, 34 indicating that the observed motion is not characterized by reptational diffusion. Furthermore, the diffusion coefficient of the large molecular weight PMMA used in this experiment was estimated to be 10 À17 to 10 À18 at 170 1C, 27,34,35 whereas the apparent diffusion coefficient until 48 h in Figure 8 was 1Â10 À16 cm 2 s À1 . The apparent diffusion coefficient is one or two orders larger than the translational diffusion coefficient of PMMA, indicating that we should consider a very fast diffusion mechanism besides the reptational one.…”

Representation of the rheological properties of polymer melts in terms of complex fluidity

“…The only uncertainty is the slope at which this value is attained at a very low frequency in the complex plane, and then this model cannot predict correct values for limiting elastic parameters such as the steady-state shear compliance j0. To test the validity of the complex fluidity representation we applied it to master curves (G', G" vs co at 220 °C) obtained with anionic PMMA of various molecular weights published by MASUDA et al [7]. Figure 8 shows the complex fluidity representation obtained with sample MF6 [7].…”

“…To test the validity of the complex fluidity representation we applied it to master curves (G', G" vs co at 220 °C) obtained with anionic PMMA of various molecular weights published by MASUDA et al [7]. Figure 8 shows the complex fluidity representation obtained with sample MF6 [7]. Curves of the same type are obtained with the other samples.…”

“…Most often the real Newtonian domain is very far from the experimental frequency range but even in this case the axis of viscosity can be described by the Cole-Cole distribution. [7], sample MF6…”