Synthesis Using a Functional Capping Agent

In this method, the polymerizable group is incorporated at the co-end of the macromonomer by a reaction between a functionalized capping agent and the living end of the polymer. To obtain well-defined macromonomers with one polymerizable end group per chain, controlled MW and narrow MWD, the following criteria should be fulfilled  

Sodium salt of malonate carbanions are known to react quantitatively with the living ends of poly(vinyl ether)s to give a stable carbon-carbon bond [45]. This reaction was performed to end-functionalize living poly(vinyl ether)s with a vinyl ether polymerizable end group using the functional malonate ion 36 [73,89]. 

IBVE was polymerized with the HI/I2 initiating system in CH2C12 at -15 °C. After complete consumption of the monomer, five equivalents of the quenching agent (with respect to the living end) were added. An instantaneous reaction was evidenced by the precipitation of sodium iodide. Poly(IBVE) with controlled MW (by the monomer to HI molar ratio) and narrow MWD was obtained as ev- 

Well-defined macromonomers of poly(BVE), poly(IBVE), and poly(EVE) with co-methacrylate end group [91] were prepared by living cationic polymerization of the corresponding monomers initiated by trifluoromethanesulfonic add in CH2C12 at -30 °C in the presence of thiolane as a Lewis base. After complete conversion, the polymers were quenched with 37 in the presence of 2,6-lu-tidine or with 41 to produce macromonomers with Mn up to 10,000 g mol-1, with narrow MWD, bearing one polymerizable methacrylate function per molecule. The same polymers were also quenched with 38 in the presence of 2,6-lutidine to give poly(vinyl ether)s with an allylic terminal group. 

A vinyl ether with a mesogenic side group, 3-[4-cyano-4 -biphenyl)oxy]propyl vinyl ether, was polymerized at 0 °C in CH2C12 with trifluoromethanesulfonic acid as an initiator in the presence of dimethylsulfide [92]. 

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