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Soluble difunctional organolithium initiators were prepared by the addition of oligomeric poly(styryllithium) to stoichiometric amounts of double 1,1-diphenylethylene (DDPE) compounds: bis[4-(l-phenylethenyl)phenyl]ether;l,4-bis(l-phenylethenyl)benzene,and4,4,-bis(l-phenylethenyl)-l,r-biphenyl.The resulting products of this addition reaction were soluble in benzene and were capable of initiating diene polymerization. A reversal was detected at the end of the addition reaction to one of the three DDPE compounds, bis[4-(l-phenylethenyl)phenyl] ether. The diphenyl ether group in bis[4-(l-phenylethenyl)phenyl] ether, which might have reacted with poly(styryllithium) to cause a shift of equilibrium, was suspected to be the cause of the anomaly. The styrene-butadiene-styrene triblock copolymer prepared from these difunctional initiators gave narrow and symmetrical chromatograms by GPC. The tensile strength of the block copolymers, however, was low. A potential route of preparing soluble organolithium initiators with functionality higher than 2 was demonstrated.

Infrared and Raman spectra of BrF5 and ClF3 in the condensed phase. Evidence of an associated state in liquid ClF3

No abstract

Triblock copolymers containing a polydiene as the center block are important thermoplastic elastomers. Commercially they are made by anionic polymerization using butyllithium initiators.' To assure the optimum polydiene microstructure for good elastomeric properties, pure hydrocarbon solvents are used in all phases of the polymerization. Many monomers requiring polar solvents or additives for polymerization cannot be conveniently used in such processes. This restriction is removed if a dilithium initiator is used to polymerize first the center polydiene block. For example, Fetters and Morton2 prepared poly(oc-methylstyrene-isoprene-oc-methylstyrene), also, Morton and Mikesell" prepared poly(ethy1ene sulfidediene-ethylene sulfide) by such a route. The initiator used by them was 1,4-dilithio-1,1,4,4-tetraphenylbutane which was prepared by the reaction of 1,l-diphenylethylene with lithium dispersion in a hydrocarbon solvent containing 15% anisole. The amount of anisole present was shown to give no ill effect on the microstructure of the polydiene block. Other known dilithium initiators are formed by the reaction of metallic lithium with an aromatic hydrocarbon4 or by the addition reaction of sec-butyllithium with di~inylbenzene~ or diisopropenylbenzene6 in hydrocarbon solvents. The last preparative route appears to be the simplest. More recently Foss, Jacobson, and Sharkeyi prepared an initiator by reacting sec -butyllithium with m-diisopropenylbenzene in cyclohexane containing a small amount of triethylamine as an additive.It has been r e p~r t e d~.~ that butyllithium adds readily to 1,l-diphenylethylene (1,l-DPE) in hydrocarbon solvents. The product can initiate isoprene and butadiene to form copolymers with 1,l-DPE but because of the bulkiness of the phenyl groups 1,l-DPE does not homopolymerize. It appears then the addition of butyllithium to compounds containing two 1,l-diphenylethylene groups should produce useful dilithium initiators. We have prepared four such double 1,l-DPE compounds: