Polyisocyanide block copolymers

Polybutadiene-block-polyisocyanide block copolymers synthesized by living transition metal catalysis were reported by Deming and Novak [110]. The catalyst used first polymerized butadiene... 

Successive addition of 1,3-butadiene and isocyanide to the solution of the Ni catalyst forms a product with flexible polybutadiene blocks and rigid polyisocyanide blocks. Although the reaction of butadiene and isoprene in the presence of CoCl2/MAO causes homopolymerization of butadiene, the reaction catalyzed by CoCl2/MAO/PPh3 affords a copolymer with 1,2-butadiene and 3,4-isoprene units [94]. The monomer reactivity ratios indicate higher reactivity of butadiene than isoprene. 

Block copolymers can often offer properties that are unattainable with simple blends or random copolymers. This led to many efforts to combine dissimilar materials, like hydrophilic with hydrophobic, or hard with soft segments, as was shown earlier. A recent paper" describes the formation of block copolymers containing helical polyisocyanide and an elastomeric polybutadiene. Compound [(7 -C3H5>-Ni(OC(0)CF3)]2 was used to carry out living polymerization of butadiene and then followed by polymerization of rm-butyl isocyanide to a helical polymer. 

Kros A, Jesse W, Metselaar GA, Comelissen JJLM (2005) Synthesis and self-assembly of rod-rod hybrid poly(gamma-benzyl L-glutamate)-block-polyisocyanide copolymers. Angew Chem hit Ed 44 4349 352... 

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