Stereospecific Polymerization of Trityl, Diphenylmethyl and Benzyl Methacrylates

Yuki Heimei, Hatada Koichi, Niinomi Toshikazu, Kikuchi Yukio

doi:10.1295/polymj.1.36

Polymerizations of trityl (TMA), diphenylmethyl (DMA) and benzyl (BMA) methacrylates were carried out mainly by n-butyllithium (n-BuLi) and the tacticities of the polymers were studied by NMR spectroscopy. Polymerization of TMA by n-BuLi gave a highly isotactic polymer in toluene as well as in tetrahydrofuran (THF). The polymer obtained in radical polymerization by AIBN catalyst had about 60% isotacticity in triads. From these results the growing-chain-controlled mechanism was proposed to this polymerization. In the polymerization of DMA by n-BuLi a highly isotactic polymer was obtained in toluene at lower temperatures and a highly syndiotactic one in THF. The radical polymerization gave a predominantly syndiotactic polymer. Temperature dependence of the NMR signal-width of the isotactic polymer indicates that the conformational arrangement of the polymer chain in solution is much rigid up to a fairly higher temperature. These results suggest that the growing-chain-controlled mechanism may contribute to some extent to the stereoregulation of DMA in toluene. BMA behaved very similarly to methyl methacrylate in the polymerization by n-BuLi. Probably the same polymerization mechanisms can be applied for both monomers. Polymerization of TMA, DMA and BMA by phenylmagnesium bromide or diethylaluminum diphenylamide was also investigated.

Stereospecific Polymerization of Trityl, Diphenylmethyl and Benzyl Methacrylates

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