Search

The single-crystal structures of imine-thioethanediyl-bridged [OSNO]-type bis(phenolato) titanium dichloro complexes were first characterized. Upon activation with appropriate aluminum compound cocatalysts, the resultant titanium complexes were moderately active towards syndiospecific styrene polymerization. Resonance signals of titanium (III) have been detected in catalytic systems of syndiospecific styrene polymerization by electron paramagnetic resonance, proving the actual active species was cationic titanium (III) complexes. Next, using the cationic titanium complexes [OSNO]Ti+-CH3 hypothetically as active species for exemplifying the initiation step of polymerization of styrene, density functional theory studies related to styrene insertion have been performed on two model molecules. In both cases, the pathway of 2, 1-insertion of styrene came out to be more favorable thermodynamically and kinetically. Moreover, the spacial repulsions among the bulky phenolato groups and the phenyl group of the incoming styrene are believed to be controlling the complexes' reactivity. [ABSTRACT FROM AUTHOR]

In the present study, polystyrene (PS) nanowires in aqueous dispersion with a diameter ranging from 120 to 300 nm are prepared via electrospun and dispersed in water. Relatively, PS nanowires confined in anodic aluminum oxide (AAO) template are prepared through drawing PS flow into the tube of AAO template. Scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) are used to characterize the size of the resultant nanowires and ensure the successful preparation of nanowires. Moreover, the glass transition and physical aging behaviors of the PS nanowires in aqueous dispersion and confined in AAO template are investigated by differential scanning calorimetry (DSC). The PS nanowires in aqueous dispersion and confined in AAO template exhibit different glass transition and physical aging behaviors. [ABSTRACT FROM AUTHOR]

We investigate the spin-3/2 baryons in the 27-plet based on flavor SU(3) symmetry. For J p = 3/2+, we find all the candidates for non-exotic members. For J p = 3/2-, we predict a new non-exotic member Λ(1780). Fitting the mass spectrum and calculating the widths of the members show an approximate symmetry of the 27-plet of SU(3). We find that the exotic members have relatively large widths and the Ξ(1950) has spin and parity J p = 3/2-. The possibility of assigning the non-exotic candidates to an octet is also analyzed. [ABSTRACT FROM AUTHOR]