Poly reptation theory

NMR data on poly(dimethylsiloxane) are shown in Figure 8-5. Typical features are that, as P increases, Dtr for a fixed N decreases sharply and tends to be insensitive to P for P somewhat leuger than N, unless N is in the region of oligomers. Those who are in favor of the reptation theory would explain the observed N dependence of in terms of the concept of tube renewal, while Tanner gave it a different interpretation. Klein [28] confirmed the insensitivity of Ptr to P above N with blended polyethylene melts. 

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