Macromonomers with Polycondensable Groups

As already mentioned, the vinyl group is not the only kind of reactive function found for the macromonomers. A macromonomer can be constituted of two condensable functions at the same chain end. The synthesis of this kind of macromonomer is quite recent, explaining the low number of publications. However, this new category of macromonomers is of great interest because the condensable functions are numerous (hydroxyl, carboxyl, amine, etc.). Table 22 gives some macromonomer structures, i.e., two condensable functions bearing a macromolecular chain. 

Unlike vinyl-type macromonomers, studies concerning macromonomers bearing two polycondensable functions are rather rare. This may be due to the rather complex syntheses of such macromonomers. In the following sections, we will describe the different methods for synthesizing both vinyl-type and polycondensable-type macromonomers. 

We will focus on recent developments made on the synthesis of macromonomers through the telomerization process. This may concern the synthe- 

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Like the telomerization process, ATRP enables the synthesis of two different types of macromonomers either with a polymerizable double bond or with a polycondensable group. As depicted in Sect. 3.1 on the design of the macromonomers, the polycondensable groups also comprise groups that afford ring-opening polymerization. 

NMP leads to a macromonomer structure by modification of either the a position or the a> position, i.e., the aminoxyl function. The a position is brought by the intiator and a chemical modification usually leads to macromonomers with two polycondensable groups. Moreover, the functionalization of the aminoxyl function will lead to macromonomers with... 

Milkovich et al.18 reacted living polystyrene with epichlorohydrin and, after hydrolysis of the epoxide ring, obtained quantitatively a macromonomer possessing at one chain end two adjacent hydroxy groups which can subsequently add to diisocyanates to yield graft polycondensates ... 

Furthermore, the group of Deimede [338-340] performed the synthesis of a-dicarboxy end-functionalized PS macromonomers by using ATRP (Scheme 72). Further polycondensation with dihydroxy end functionalized polyethylene oxide) led to alternating branched PS/poly(ethylene oxide) poly(macromonomers) (Scheme 72). These novel amphiphilic compounds afforded the formation of stable micelles, especially in THF or dioxane. 

Polycondensation techniques have been employed for the synthesis of macromonomers. Depending on the nature of the functional end group the copolymerization with comonomers can be performed with addition polymerization techniques, giving rise to very interesting graft copolymer structures. 

Figure 7.1 shows a schematic chemical synthesis of different chanicals required to prepare linear Seesaw-type macromonomer chains with two azide end groups and one middle alkyne group as well as the self-polycondensation via cUck chemistry between azide and alkyne. 

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