Comb macromolecule

Fig. 27. Molar mass dependence of [rj] for a fractionated comb macromolecule. The fractionation was made with a SEC/LALLS/VISC set-up. The comb macromolecule consists oi a polyimidazole backbone prepared by free radical polymerization. The imidazol side groups acted in a melt with phenylglycidylether and phthalic anhydride as multifunctional initiator for the anionic growth of polyester chains. The straight lines correspond to the behavior of unattached polyester chains and the comb polymers at low and high molar masses respectively [136]...

This section on the contraction factor may be concluded with an example of a comb macromolecule [136]. Due to the route of preparing this comb, unattached side chains also occurred in the system. Figure 27 shows the result of the molar mass dependence of [rj] which was obtained from a SEC/LALLS/VISC fractionation. One observes at low molar masses a straight line with an exponent of 11 =0 JO that coincides with the exponents of linear side chains. It follows a... 

Note 1 If the bchains between the branch points of the main chain and the terminal svhchains of the main chain are identical with respect to constitution and degree of polymerization, and the siAQ-chains are identical with respect to constitution and degree of polymerization, the macromolecule is termed a regular comb macromolecule. 

Polymer composed of regular macromolecules, regular star macromolecules, or regular comb macromolecules. 

In 1985, application of this simple dendritic construction to a polymer core, specifically chloromethyl functionalized polystyrene was reported. 139 Another example of the identical procedure was reported 140 except utilizing another polymeric core backbone, derived from a functionalized vinyl ether monomer. These are very early examples of dendritic comb macromolecules. 

Prosa, T.J., Winokur, M.J., Moulton J., Smith R, and Heeger, A.J., X-ray structural studies of poly(3-alkylthiophenes) An example of an inverse comb. Macromolecules 25, 4364, 1992. 

An lUPAC publication (11) discusses both structure-based and source-based representations of comb polymers acomb polymer is described as a macromolecule comprising a main chain with trifunctional points from which linear side chains emanate. If the subchains between the branch points of the main chain and the terminal subchains of the main chain are identical with respect to constitution and degree of polymerization, and the side chains are identical with respect to constitution and degree of polymerization, the macromolecule is termed a regular comb macromolecule. If at least some of the branch points are of functionalities greater than three, the macromolecule may be termed a brush macromolecule. 

Femyhough, C.M., Young, R.N., Poche, D., Degroot, A.W., Bosscher, F., Synthesis and characterization of polybutadiene and pofy(ethylene-l-butene) combs. Macromolecules 2001, 34 7034—7041. 

Figure 21.9 Statistical analysis of the number of branches over a set of star comb macromolecules obtained by the convergent approach.

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