Synthesis of hydrophilic isotactic polypropylenes promoted by metallocene catalysts

In this paper, the synthesis of isotactic polypropylenes (i-PP) modified with [BOND]OH groups in sides (iPP-OH), by combination of polyinsertion ansa-metallocene catalysis and ring opening of propene oxide (PO), is described. i-PP sequences interrupted by isolated ethylene/p-methylstyrene units forms the backbone. This enchainment is obtained by controlled copolymerization of propene with ethylene and p-methylstyrene comonomers in the presence of rac-ethylenebis(1-indenyl)zirconiumdichloride/methylalumoxane system. The metallation reaction of the p-methyl group with sec-BuLi generates an anionic center that can be reacted with PO. The iPP-OH is the result of the monoaddition reaction of PO followed by hydrolysis with acidified methanol. By changing experimental conditions in the backbone synthesis, a tuned number of the functionalizable sites as well as polypropylene sequence lengths can be obtained. As a consequence, iPP samples with a different number of [BOND]OH groups for the backbone can be synthesized after the PO monoaddition reaction.