ABSTRACT:Polymerizations of various methacrylates and 0(-(p-substituted phenyl)acrylates were studied in toluene and tetrahydrofuran by several anionic initiators. The polymerization with octylpotassium in tetrahydrofuran was found to be the most suitable for the formation of the heterotactic polymer, defined as the polymer containing more than 50% heterotactic triads. Methacrylic acid esters of the primary alcohol gave the heterotactic polymers, whose heterotactic contents increased with an increase in the bulkiness of the ester group. Methacrylic esters of secondary alcohol generally gave heterotactic polymers with octylpotassium in tetrahydrofuran. In the polymerizations of methacrylic acid esters of tertiary alcohol, the heterotactic contents decreased with an increase in the bulkiness of the ester group. A perfectly atactic polymer was obtained in the polymerization of methyl 0(-phenylacrylate with butyllithium in tetrahydrofuran, but it gave the heterotactic polymer when initiated with octylpotassium in tetrahydrofuran. Methyl 0(-pchlorophenylacrylate produced the heterotactic polymer in tetrahydrofuran with butyllithium as well as with octylpotassium. In the case of methyl 0(-p-bromophenylacrylate, the heterotactic polymer was obtained even in the polymerization in toluene with butyllithium. These results indicate that the acrylic acid ester having the bulkier substituent tends to give the.heterotactic polymer more easily by anionic initiator. KEY WORDSHeterotactic Polymer / Alkyl Methacrylate / ()(-Substituted Acrylate / Methyl Methacrylate / Methyl 0(-Phenylacrylate / Cyclohexyl Methacrylate / Octylpotassium / Fluorenylcesium/ 13 C-NMR Spectrum / Glass Transition Temperature/ Many papers have been published on polymerization in which highly isotactic or syndiotactic polymers were obtained. However, there have been few publications concerning the formation of heterotactic polymers. Heterotactic poly(vinyl alcohol) was reported by Nozakura et al. 1 • 2 and heterotactic poly(acetaldehyde) by Brame and Vogl,3 and Goodman and Brandrup. 4 A polymer having more than 50% portion ofheterotactic triads should be defined as a heterotactic polymer since the heterotactic contents can attain at most 50% even when the regulation in the polymerization is sterically random. The formation ofheterotactic polymer appears to be very interesting since a higher order of stereoregulation would be required for the heterotactic polymerization than for the isotactic or syndiotactic one.In our previous paper 5 the formation ofheterotactic polymers of methyl a-(p-bromophenyl)acrylate and methyl a-(p-chlorophenyl)acrylate was briefly reported. In this work, we have studied the anionic polymerizations of various methacrylates and aphenylacrylates under various conditions, and found that the bulkiness of a-substituent was one of the important factor necessary for the heterotactic growth in the polymerization and that the polymerization in tetrahydrofuran initiated with octylpotassium was suitable for the formation of the heterotactic ...

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