Other synthetic routes include: controlled sol-gel processes, group transfer polymerization, transition metal catalysis, living anionic polymerization, living cationic polymerization, ring opening polymerization, ring-opening metathesis polymerization (ROMP), and controlled radical polymerization.
In the core-first approach (also known as the "arm-out" or divergent approach[REF]), a multifunctional core serves as the initiator simultaneously for several arms.