End functionalization of hyperbranched poly(siloxysilane): Novel crosslinking agents and hyperbranched–linear star block copolymers

Functionalized hyperbranched poly(siloxysilane)s have been prepared by hydrosilylation reactions involving the multiple silicon hydride (SiH) groups of the polymer to introduce other reactive groups such as epoxy, amine, and hydroxyl groups. The possible use of these modified polymers as novel crosslinking agents is discussed. The same hydrosilylation reaction is used to attach preformed linear poly(isobutylene) (PIB) or poly(ethylene oxide) (PEO) onto the hyperbranched polymer to afford unusual hyperbranched–linear star block copolymers. The PIB-derived copolymer is shown to be very hydrophobic, whereas its PEO-derived counterpart is amphiphilic.