ANIONIC-POLYMERIZATION OF MONOMERS CONTAINING FUNCTIONAL-GROUPS .5. ANIONIC POLYMERIZATIONS OF 2-CYANOSTYRENE, 3-CYANOSTYRENE, AND 4-CYANOSTYRENE

Anionic polymerizations of 4-cyanostyrene (1), 3-cyanostyrene (2), and 2-cyanostyrene (3) were carried out in tetrahydrofuran (THF). The initiators included lithium naphthalenide, potassium naphthalenide, oligo(alpha-methylstyryl)dilithium and -dipotassium, (1,1,4,4-tetraphenylbutanediyl)dilithium and -dipotassium, [1,1-bis[4'-(trimethylsilyl)phenyl]hexyl]lithium, and [1,1,4,4-tetrakis[4'-(trimethylsilyl)-phenyl]butanediyl]dipotassium. The polymerization of 1 proceeded quantitatively with each of these initiators at -78-degrees-C for 30 min. The resulting polymers all possessed molecular weights predicted from the molar ratios of monomer to initiator and narrow molecular weight distributions (MWDs). The persistency of propagating activity at the chain end of poly(1) was confirmed by the quantitative initiation efficiency in the postpolymerization at -78-degrees-C. These results strongly indicated that the anionic polymerization of 1 afforded a stable living polymer under the conditions. The Mark-Houwink equation for poly(1), [eta] = 1.004 x 10(-4)M0.749 (in N,N-dimethylformamide at 40-degrees-C), was correlated. New block copolymers, poly(1-b-styrene-b-1) and poly(methyl methacrylate-b-1-b-methyl methacrylate), could be synthesized by using a living polymerization system of 1. The results of the polymerization of both 2 and 3 were not very satisfactory from the viewpoint of living polymerization. The polymerization of 2 did not occur at -78-degrees-C at all but proceeded quantitatively with warming to -30-degrees-C. However, undesirable side reactions might considerably occur at this temperature from the fact that the resulting poly(2) had a somewhat broad MWD. The anionic polymerization of 3 gave polymeric products having low molecular weights only in a 30% yield even for the longer reaction time of 200 h at -78-degrees-C. The resulting poly(3)s were again found to have broad MWDs.