NSE Studies on Entangled Polymer Melts

2 NSE Studies on Entangled Polymer Melts Poly(tetrahydrofurane) (PTHF) 

0 Fit with local reptation. d Fit with the des Cloizeaux model. 

With respect to the intensity resolution relationship of NSE, PEB-2 [essentially PE with one ethyl branch every 50 main chain bonds the sample is obtained by saturating 1-4 polybutadiene, the residual 1-2 groups (7%) cause the ethyl branches Mw = 73200 g/mol Mw/Mn = 1.02] has two advantages compared to PEP (1) the Rouse rate W/4 of PEB-2 is more than two times faster than that of PEP at a given temperature [W/pEP (500 K) = 3.3 x 1013 A4s 1 W/pEB (509 K) = 7 x 1013A4s-1] (2) at the same time, the topological constraints are stronger. 

Finally, Fig. 27 compares the PE-data with the predictions of the rubber-like model of des Cloizeaux [51]. This model describes the experimental data very appropriately over the entire range of the scaling variable observed. In particular, we note that compared to the Ronca model description the predicted Q splitting is less pronounced and much closer to the experimental observation. In his analysis des Cloizeaux derives a mean distance squared between entanglement of S2 = 12.55 nm2. In order to compare results with the entanglement 

So far, the existence of a well-defined entanglement length in dense polymer systems has been inferred indirectly from macroscopic experiments like measurements of the plateau modulus. However, its direct microscopic observation remained impossible. The difficulty in directly evaluating the entanglement 

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