Enhancing Mechanical Properties of Graft-Type Nanocomposites Using Organically Modified SiO and Polypropylene Containing Reactive Methoxy Groups.

In situ grafting of a reactive matrix and nanofillers is a promising strategy to fabricate graft-type polypropylene (PP)-based nanocomposites, where the grafting efficiency is affected by the initial dispersion of nanofillers in the matrix. In this work, influences of surface organic modification of nanofillers were investigated on properties of PP/SiO nanocomposites using poly(propylene-co-octenyltrimethoxysilane) as a reactive matrix. The surface modification of SiO, especially with longer alkyl chains, led to improved dispersion of nanoparticles, thus promoting the grafting reaction and mechanical properties.

Highly linear polyethylenes tailored with 2,6-bis[1-(p-dibenzo-cycloheptylarylimino)ethyl]pyridylcobalt dichlorides.

A novel family of 2,6-bis[1-(p-dibenzocycloheptylarylimino)ethyl]pyridylcobalt dichlorides Co1-Co4 were synthesized and fully characterized by FT-IR, 1H NMR, and elemental analysis as well as X-ray diffraction analysis. The 1H NMR spectra of these paramagnetic cobalt complexes Co1-Co3 showed similar spectra with one set of signals, while Co4 possessed two sets of signals due to the different conformations caused by different substituents on the ortho-position of the N-aryl group. Crystal structures of Co1, Co2 and Co4 revealed similar square-pyrimidal geometry around the cobalt ion, in which two dibenzocycloheptyl groups adapted as cis-conformers, whereas Co3 possessed bistrigonal geometry and the two dibenzocycloheptyl groups were adapted as trans-conformers.

Dialkylaluminum 2-substituted 6,6-dimethylcyclopentylpyridin-7-oxylates toward structural-differentiation of the ring-opening polymerization of ε-caprolactone and l-lactides.

Herein, a series of dialkylaluminum 2-substituted 6,6-dimethylcyclopentyl pyridin-7-oxylates Al1-Al7 were synthesized and characterized by 1H- and 13C-NMR spectroscopy and elemental analysis. The molecular structure of Al3 was proven to be a dimer of an aluminum complex. These aluminum complexes could efficiently initiate the ring-opening polymerization (ROP) of ε-caprolactone (CL), and the structural differentiations of the resultant PCL were strongly dependent on the amount of BnOH (PhCH2OH) used.