The anionic copolymerization of 5‐(N,N‐diisopropylamino)isoprene with styrene

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Abstract
The anionic copolymerization of 5‐(N,N‐diisopropylamino)isoprene (N,N‐diisopropyl‐2‐vinylallylamine) and styrene initiated with alkyllithium compounds is studied. Copolymers obtained from different compositions are characterized by size‐exclusion chromatography (SEC), differential scanning calorimetry and by 1H NMR and 13 C NMR spectroscopy. Under these conditions the dialkylaminoisoprene, similar to butadiene and isoprene, is more reactive than styrene and is incorporated faster into the polymer backbone. The incomplete conversion of the monomers has been attributed to the formation of intra‐or intermolecular complexes between the Li+ counterion at the chain end and amino groups. Because of the polarity of the aminoisoprene, no tapered copolymer is obtained, contrary to the isoprene/styrene system. The reactivity ratios of the monomers calculated according to Kelen‐Tudos show that the styryl anion reacts preferably with an aminoisoprene monomer, while the aminoisoprenyl anion tends to homopolymerize.