Polymer tube axis

Figure 3 Liquid crystalline (A) and gel-based alignment medium (B) at various stages (A) dry PBLG and the readily prepared lyotropic mesophase. (B) Cross-linked PS as an unswollen polymer stick in a standard NMR tube (left), polymer stick directly after polymerization, fully swollen polymer stick, polymer stick swollen in an NMR tube with an effective stretching along the tube axis (right). (Reproduced from refs. 17 and 53 with permission from Wiley-VCH Verlag GmbH Co. KGaA (Copyright).)...

This potential can be expanded significantly by the use of an installation (Fig. 3.37) for the application of pol3mier powder compositions [66]. The gas-polymer powder mixture is fed from the source into helix 2 of the vortical tube and is transported in a spiral stream 3 to socket 4. Inhibitor-1 is supplied from source 5 to a gap between socket 4 and cylindrical female mouthpiece 6 fixed on helix 2 face of the vortical tube and moves in the gap in a spiral stream 7. lnhibitor-2 fed from source 8 is sprayed in flow 9 through nozzle 10 installed along the swirl tube axis. 

Interestingly, it does not matter how we are going to perform work we can squeeze polymer from the sides or we can pull it by the ends, the amount of work should not depend on that (the beauty of entropy and Boltzmann principle ). But if we are talking about pulling the ends, it is more convenient to use end-to-end distance R instead of D. How are they related For each segment, its projection along the tube axis is D ... 

Now let s calculate the longest relaxation time t for a polymer melt. As we have said, it is the time that a reptating chain takes to leave its original tube. To do this, the chain obviously has to diffuse along the tube axis by a distance of order A. 

The translational motion is easily analysed. The motion of the polymer parallel to the tube axis, which is nearly parallel to u, is not hindered by the tube, so that the parallel component will be nearly equal to the diffusion constant in dilute solution Z> o-t On the other hand, the perpendicular motion is limited to within the distance a, so that the perpendicular component can be regarded as zero provided the small-scale motion of order a is neglected. Thus... 

The enhanced recovery characteristics were thought to be associated with the synergism between the anisotropic SWCNTs and the crystallizable switching segments of the polymer. The extent of SWCNT orientation in the direction of deformation (tube axis parallel with applied stress) increased with SWCNT concentration. In conjunction, the polymer crystallite fraction increased with SWCNT concentration. 

The reptation model also predicts a second type of diffusion constant. The diffusion constant Dtube cannot be readily measured because experiments cannot track how the chain moves along its tube axis. But you can measure a diffusion constant D that describes how the center of mass of the polymer chain moves in space over time. In this case, the average distance moved is (x-) oc Rj, where = Nb . The reptation model Equation (33.38) predicts that chain diffusion slows as the square of the chain length. 

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