SYNDIOTACTIC POLYMERIZATION OF STYRENE - MODE OF ADDITION TO THE DOUBLE-BOND

In order to complement the basic information concerning the sterochemical reaction mechanism we report in this paper the mode of addition of the growing chain end to the double bond of the monomer. The **1H NMR spectrum of the syndiotactic copolymer of cis styrene- beta -d (15% mole fraction) with perdeuteriostyrene (85% mole fraction) is reported. The resonance of the aliphatic protons consists of two doublets at 1. 23 (methylene) and 1. 75 ppm (methine). The spacing between the components of the doublets is 9//. //0 Hz. The spacing corresponds to J OVER BAR //1//2 thus showing that the methylene and the methine protons are arranged as discussed, this shows that the actual mode of addition of the growing chain end to the double bond of the monomer is cis.