Polymeric organolithium compounds branching reactions

Polymeric organolithium compounds react simply and quantitatively with 1,1-diphenylethylenes [3, 109]. These reactions have provided a new methodology for the synthesis of star-branched polymers, internally-functionalized polymer chains and stars, as well as heteroarm, star-branched polymers via living linking reactions as shown in Scheme 33 [3, 202, 203, 207]. 

The efficiency of postpolymerization linking reactions of polymeric organolithium compounds with polyhalosilanes is utilized in a number of commercial processes [7]. The melt viscosity (high shear) and cold-flow (low-shear) properties of linear elastomers with narrow molecular weight distributions are poor. These limitations are eliminated by postpolymerization branching reactions such as linking with polyhalosilanes [7,25,26]. 

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