Molecular weight distribution deconvolution

The copolymer prepared without DEZ is clearly shown to be bimodal by GPC, with MJMn = 13.8 (Fig. 16). The GPC trace was deconvoluted into components of Mw 240,000 and 9600 g mol reflecting the differing propensities for hydrogen-induced termination between the two catalysts. The molecular weight distribution narrows as DEZ is added, as expected for an efficient chain shuttling polymerization ... 

There are many facets of this study which we feel merit further investigation. In particular it is necessary to consider am extension of the proposed model, which in its present form is confined to the performance of a simple column, to cover the behaviour of any set of columns since it is column sets which are normally used. In addition, it is important to consider the input to the model which should be truly representative of polymers with a molecular weight distribution and not merely a concentration pulse of perfectly monodisperse polymer. In relation to this latter suggestion it would be significant if it were possible to link this model to the very real problem of deconvolution, i.e. the removal of instrumental and column broadening from the observed chromatogram to produce the true molecular weight distri-... 

Schimpf, M.E. Williams, P.S. Giddings, J.C. Accurate molecular weight distributions of polymers using deconvolution to remove system dispersion. J. Appl. Polym. Sci. 1989, 37, 2059-2076. 

Table 3.1 A portion of the membership of the ALIS screening library, composed of NG LI 27A443 (library 3 in this table) and four other libraries, which yields DHFR ligand 1 (NCD-157, entry 11). Compounds of similar exact molecular weight (EMW) are distributed among the five pooled libraries to minimize mass overlap and simplify hit deconvolution. Reprinted from [40] with permission from Elsevier.

In the case of SEC/FTIR characterization, a method for recovering the full distribution from the average comonomer composition was proposed based on a polymerization kinetics model and the deconvolution of the MWD [43]. It was found, however, that both SEC/FTIR and P-Tref/light scattering techniques generally lose part of the information on the bivariate distribution of molecular weight and comonomer composition [44]. 

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