We report an effective strategy for the synthesis of semi-crystalline block copolyethers with well-defined architecture and stereochemistry. As an exemplary system, triblock copolymers containing either atactic (racemic) or isotactic (R or S) poly(propylene oxide) end blocks with a central poly(ethylene oxide) mid-block were prepared by anionic ring-opening procedures. Stereochemical control wa...

The alkylaluminum-complexed zirconocene trihydride cation [(SBI)Zr(μ-H)(3)(Al(i)Bu(2))(2)](+), which is obtained by reaction of (SBI)ZrCl(2) with [Ph(3)C][B(C(6)F(5))(4)] and excess HAl(i)Bu(2) in toluene solution, catalyzes the formation of isotactic polypropene when exposed to propene at -30 °C. This cation remains the sole observable species in catalyst systems free of AlMe compounds. In the...

The effect of nanofilles additives containing copper oxide nanoparticles stabilized by a polymer matrix high-pressure polyethylene obtained the mechanochemical method on features structure and properties metal-containing nanocomposites based isotactic polypropylene was studied using differential thermal (DTA) X-ray phase (XRD) analyzes. improvement strength, deformation rheological parameters, ...

We study the mutual interactions of simple parallel polymers within the framework of density-functional theory (DFT). As the conventional implementations of DFT do not treat the long-range dispersion [van der Waals (vdW)] interactions, we develop a systematic correction scheme for the nonlocal energy contribution of the polymer interaction at the intermediate to the asymptotic separations. We p...

Theoretical calculations are performed to explore the origin of inherent tacticity in bulky methacrylates. Geometries and conformer distributions of monomers and oligomeric propagating radicals are calculated to study the impact of steric bulk and π-stacking interactions on the preferences for meso versus isotactic propagation. Consistent with the previous qualitative analyses by Satoh and Kami...

The physicochemical properties of polymers can be modified by spatial configuration. Here, dielectric spectroscopy (DS) was employed to investigate the effect tacticity on glass-transition dynamics confined polymer films. We have also carried out relaxation studies at ambient and elevated pressure conditions. High-pressure measurements provide information sensitivity density changes, which help...

Isotactic-poly(1-butene) (iPB1) shows superior mechanical properties after crystal–crystal transitions. Recently, Miyoshi et al. found that crystalline stems in metastable tetragonal crystal perform uniaxial rotational diffusions accompanying side-chain conformational transitions in the fast motional limit (correlation time, /scS o10 7 s; Macromolecules 2010, 43, 3986– 3989.). In this study, mo...