Methods Based on Double Reptation

He reports that it is possible to find data sets in the literature that appear to support each of these scalings but that the difference is not very important. Also, Colby and Rubinstein [19] suggest that the dilution effect in a theta solvent should yield a concentration scaling exponent of 7/3 rather than 2. This is discussed in more detail in Section 9.3.2. 

Therefore, Tuminello [16] assumed a plot of [1 - (G /G ) ] versus is closely related 

The scales on the [G co)/Glif versus (1/ ) plot can now be shifted to yield the final estimate of the cumulative or differential molecular weight distribution. Tuminello et al. [20, 21 ] used this technique to determine the MWD of several fluoropolymers that could not be analyzed using GPC due to their insolubility. 

McGrory and Tuminello [22 ] examined the possibility of using stress relaxation data in place of the storage modulus to determine MWD. Thus, in place of the plot of [G ( y)/G f versus (1/ ) as the basis for constructing the molecular weight distribution, a plot of [G(t)/ G f 

In Chapter 6, the double reptation modification of the Doi-Edwards reptation for poly-disperse systems was introduced, and we repeat the basic idea here as Eq. 8.30. 

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