Complex macromolecular architectures utilizing metallocene catalysts

Graft copolymers having poly(methyl methacrylate), PMMA, backbone and polystyrene, PS, polyisoprene, PI, poly(ethylene oxide), PEO, poly(2-methyl-1,3-pentadiene), P2MP, and PS-b-PI branches were prepared using the macromonomer methodology and high-vacuum techniques. The methacrylic macromonomers, mMM, were synthesized by anionic polymerization, whereas their homopolymerization and copolymerization with MMA were performed by metallocene catalyst. Relatively high macromonomer conversions were obtained in all cases. The parameters affecting the polymerization characteristics were examined. Well-defined poly(butyl methacrylate)-b-poly(methyl methacrylate) block copolymers were prepared for the first time by sequential addition of monomers starting from n-butyl methacrylate. The samples were characterized by size exclusion chromatography, SEC, 1H and 13C NMR spectroscopy, low-angle laser light scattering, LALLS, and differential scanning calorimetry, DSC

Metallocene-catalyzed copolymerization of MMA with anionically synthesized methacryloyl macromonomers

Well-defined graft copolymers with poly(methyl methacrylate) backbone and poly(styrene) (PS), poly(isoprene) (PI), or poly(dimethylsiloxane) (PDMS) branches were synthesized by combining anionic and metallocene catalyzed polymerization. The synthetic strategy involves the preparation of methacryloyl macromonomers of PS, PI, and PDMS by anionic polymerization, followed by copolymerization with methyl methacrylate using the highly reactive catalytic system Cp2ZrMe2/B(C6F5)3/ZnEt2. The macromonomers and the fractionated graft copolymers were characterized by size exclusion chromatography, low-angle laser light scattering, and 1H NMR spectroscopy

Zirconocene-catalyzed copolymerization of methyl methacrylate with other methacrylate monomers

Statistical copolymers of methyl methacrylate (MMA) with n-butyl-, s-butyl, t-butyl-, n-hexyl-, decyl-, stearyl-, allyl-, trimethylsilyl- and trimethylsilyloxyethyl methacrylate were prepared by zirconocene-catalyzed copolymerization. The reactivity ratios of MMA copolymers with butyl-, hexyl-, and stearyl methacrylate were estimated using the Finemann-Ross, the inverted Finemann-Ross, and the Kelen-Tüdos graphical methods. Structural parameters of the copolymers were obtained from the calculated dyad sequences, derived by using the reactivity ratios. The effect of the nature of the methacrylate ester group and the catalytic system used on the copolymer structure is discussed. The glass-transition temperature (Tg) values of MMA copolymers with butyl- and hexyl methacrylate were measured and examined in the frame of several theoretical equations, allowing the prediction of these Tg values. The best fit was obtained using Barton and Johnston equations, taking the monomer sequence distribution of the copolymers into account. © 2004 Wiley Periodicals, Inc

Ring-opening polymerization of lactones using zirconocene catalytic systems: Block copolymerization with methyl methacrylate

The ring-opening polymerization of ε-caprolactone (ε-CL) and δ-valerolactone (δ-VL) using nine catalytic systems consisting of a combination of three C2V zirconocene complexes and three borate cocatalysts is discussed. The polymerizations proceed in a well-controlled manner, producing polymers with relatively high molecular weights and narrow molecular weight distributions. Kinetic experiments of the polymerization of ε-CL with the catalytic system Cp2ZrMe2/B(C 6F5)3 (1) showed a linear dependence between polymerization yield and molecular weight with time, as well as between the molecular weight with the molar ratio of the monomer over the catalyst [e-CL]/[Zr], indicating sufficient control of the polymerization reaction. The catalytic system (1) was utilized for the synthesis of well-defined block copolymers of MMA with ε-CL and δ-VL. All samples were characterized by size exclusion chroma-tography, nuclear magnetic resonance, and differential scanning calorimetry. © 2007 Wiley Periodicals, Inc