POLY(ALPHA-METHYLENE-GAMMA-BUTYROLACTONE) SYNTHESIS, CONFIGURATIONAL STRUCTURE, AND PROPERTIES

α-Methylene-γ-butyrolactone (α-MBL, I) has been shown tobe a reactive vinyl monomer capable of both free-radical and anionic polymerization. High-resolution 13C NMR was found to be of particular value in determining the configurational microstructure of the polymers using the quaternary carbon as the stereochemical probe. Poly(α-MBL) from free-radical initiation was found to be atactic with slight preponderance of syndiotactic placements (Pm ≃ 0.37) with very little dependence of the tacticity on the temperature of the polymerization. Anionic polymerization with PhMgBr in toluene and 9-fluorenyllithium in THF at -78 °C yielded polymers that on the basis of present assignments are predominantly isotactic (Pmm = 0.73, 0.75, respectively). Poly(α-MBL) from free-radical polymerization is amorphous and has a high glass transition temperature (Tg =195 °C) and solvent resistance, characteristic of structural rigidity of the chain segments. © 1979, American Chemical Society. All rights reserved.