MULTI-ARM STAR POLYMERS HAVING A WELL-DEFINED CORE AND METHODS FOR THE SYNTHESIS THEREOF

摘要

The synthesis of star polymers having well-defined arms emanating from well-defined and readily controllable calix[n]arene (n=4 to 16) cores are described. The synthesis is particularly suitable for polyisobutylene and/or polysiloxane star polymers. The synthesis has been achieved using carbocationic and/or anionic ring opening polymerization techniques to form polymer arms of desired molecular weights, then separately preparing the calixarene derivative core, and finally, linking the arms to the core by transesterification or hydrosilation. The star polymers are usable as viscosity modifiers and oil additives since they are less sensitive to oxidative reactions and shear stable.