CHE 381 Lecture Notes - Lecture 17: Size-Exclusion Chromatography, Stereoselectivity, Dow Chemical Company
Document Summary
Unprecedented insertion of styrene single units in polyisoprene using borohydrido rare earths / dialkylmagnesium catalysts : a new family of sbr rubbers. Philippe zinck*, micha l terrier, andr mortreux, andreia valente and marc visseaux* Unit de catalyse et chimie du solide, umr cnrs 8181, Enscl, cit scientifique, 59652 villeneuve d"ascq, france marc. visseaux@ensc-lille. fr. The introduction of functional groups such as styrene in the backbone of polydienes is of interest for many fields of applications. Styrene-dienes copolymers commonly referred to as sbr rubbers were initially synthesized by radical and anionic processes, yielding poorly stereoregular materials. Higher selectivities[1] were achieved with the development of transition metal catalysis. Poly(1,4-cis butadiene co-styrene) was by far the most widely studied sbr,[2] probably due to low price of butadiene vs. other conjugated dienes. Besides petroleum derivatives, isoprene was also used as a monomer for random copolymerization with styrene. This field was pioneered by radical polymerization in emulsion in water using potassium persulfate as initiator.
