Star Combs with PCEVE Backbone and PS Branches

4 Star Combs with PCEVE Backbone and PS Branches (Deffieux and Schappacher, 1999) 

The divergent or core-first method This consists of the initiation of a controlled polymerization from a multifunctional initiator, which serves finally as the star central core. This technique requires a controlled and quantitative initiation followed by a living-like polymerization process without transfer or termination. In most cases, stars obtained by this approach possess a limited number of branches typically between three to five or six. A precise determination of the number of star branches using conventional characterization techniques is not easy and generally average values can be obtained. 

The convergent or arm-first method This consists first in the synthesis of arms by a living/ controlled polymerization. The latter are finally linked to each other by adding a multifunctional agent to the polymerization system. Addition of a small amount of a bis-monomer 

Stars constituted of monomer units bearing reactive functions, prepared by these different strategies have been used as precursor for the construction of the corresponding comb star polymers. As explained in the previous section, different methodologies can be used branches can be introduced on the star backbone by either grafting-from or grafting-onto approaches. 

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