ALLYLTRIMETHYLSILANE POLYMERS FROM METALLOCENE CATALYSTS - TACTICITY AND STRUCTURAL CHARACTERIZATION

The synthesis of isotactic, syndiotactic and atactic poly(allyltrimeth ylsilane) (PATMS) is described, along with the characterization of the se polymers using thermal methods, X-ray diffraction, solution and sol id-state nuclear magnetic resonance (n.m.r). Isotactic PATMS was produ ced from rac-Me2SiInd2ZrCl2/MAO (methylalumoxane) and displayed chains with an s(3/1) symmetry in the crystalline domains. Syndiotactic PATM S, produced from Me2C(Cp)(Flu)ZrCl2/MAO, was a semicrystalline polymer with chains in the crystalline phase exhibiting s(2/1)2 helical symme try. A combined X-ray diffraction and solid-state n.m.r. analysis on p oorly crystallized samples of syndiotactic PATMS indicates the occurre nce in the crystalline phase, for given crystallization conditions, of disorder in the packing of chains, which preserve the helical conform ation. Atactic PATMS, an amorphous polymer, was produced using an Ind2 ZrCl2/MAO catalyst.