Novel Thermoplastic Elastomers: Star-Blocks Consisting of Eight Poly(Styrene-b-Isobutylene) Arms Radiating from a Calix[8]Arene Core

Abstract

Abstract The first synthesis by a core-first strategy of novel star-block copolymers consisting of eight poly(styrene-b-isobutylene) (PSt-b-PIB) arms radiating from a calix[8]arene core is described. An octafunctional methoxy calix[8]arene derivative was used to initiate the living polymerization of isobutylene (IB) to desirable molecular weights, then styrene (St) was added to obtain the sought star-blocks. Molecular weights and PSt contents were determined by triple-detector GPC and 1H NMR spectroscopy. Star-block thermoplastic elastomers containing 17–32% PSt showed high strength and elongation (up to ∼26 MPa and >500%) and relatively low melt viscosities. The mechanical and rheological properties of these star-blocks are superior to those of linear PSt-b-PIB-b-PSt triblocks. PIB-based thermoplastic elastomers may be of use as novel biomaterials.