The Effect of Stereochemistry in Anionic Polymerization Modifiers

The influence of stereochemistry of polar modifiers on the microstructure of polybutadiene and poly(styrene-co-butadiene) was evaluated for 2,2’-ditetrahydrofurylpropane (DTHFP). The meso and D,L diastereomers were isolated from commercial 50/50 mixtures through column chromatography and characterized by ¹H NMR and GC/MS. The meso-DTHFP was found to be more active than D,L-DTHFP in incorporation of vinyl during anionic polymerization. To form a polymer with approximately 55% vinyl, twice the amount of D,L-DTHFP was required compared to using pure meso-DTHFP. The mechanism for this effect will be discussed.