Propene-hexene copolymers crystallize in a new polymorphic form of isotactic polypropylene when the concentration of hexene is higher than nearly 10-15 mol %. The hexene units are included in the crystals, inducing an increase of density that allows crystallization of 3-fold helical chains in a trigonal unit cell according to the space group R3c or Rc, where the helical symmetry of the chains i...

The polymerization of racemic lactide with a racemic aluminum alkoxide catalyst is reported. Microstructural analysis of the polymer produced with H NMR spectroscopy revealed that an isotactic stereoblock poly(lactic acid) formed, where each enantiomerically pure block contained an average of 11 lactide monomer units. The melting point of this polymer, 179 °C, was higher than that of the enanti...

Poly(vinylpyridine oxides) in pneumo-coniosis research. Schlipkoter and Brockhaus of the Institut fur Lufthygiene Dusseldorf found that poly(2-vinylpyridine 1-oxide) can inhibit the fibrosis normally produced by quartz dust in the lungs or other tissues of animals. Later research in Germany and elsewhere has confirmed the earlier observations. The polymer is active when the quartz is administer...

Electrical properties of three kinds of poly(methyl methacrylate) (PMMA) with different tacticity, i.e. isotactic(i), syndiotactic(s), and atatic(a), were investigated for the application in field effect transistor. Metal-insulator-silicon structures were fabricated via spin coating PMMA on heavily doped p-type silicon (p-Si) followed by evaporating gold electrode. The electrical characteristic...