A process for preparing asymmetric radial polymers

摘要

Prodn. of a predominately four-armed asymmetric radial block copolymer contg. predominately two arms which are copolymers of a conjugated diene(s) and a vinyl aromatic hydrocarbon, and two conjugated diene homopolymer or copolymer arms, comprises: (1) anionically polymerising a conjugated diene monomer(s) and a vinyl aromatic hydrocarbon monomer(s) to form a set of living polymer arms; (2) anionically polymerising a conjugated diene monomer(s) to form another set of living polymer arms; (3) coupling one set of living polymer arms with a coupling agent selected from tetramethoxysiliane and gamma-glycidoxypropyl trimethoxysilane; (4) substantially completing the coupling reaction while leaving, on ave., two unreacted coupling sites on the coupling agent; (5) adding the other set of living polymer arms to the prod. of (4) and coupling the other set to the first coupled set of polymer arms; and (6) opt. hydrogenating the coupled polymer, either partially or fully. Also claimed is the prod. of such a process.