G. Cai, W. P. Weber
Oct 25, 2000
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0
Influential Citations
9
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Journal
Macromolecules
Abstract
Poly(1-dimethylsiloxypentamethyltrisiloxane) (II) has been prepared by anionic ring-opening polymerization (AROP) of 1-dimethylsiloxypentamethylcyclotrisiloxane (I) catalyzed by butyllithium and HMPA. The isomeric polysiloxane, poly(1-hydrido-1-trimethylsiloxytetramethyltrisiloxane) (IV), has been prepared by AROP of 1-hydrido-1-trimethylsiloxytetramethylcyclotrisiloxane (III) catalyzed by dilithiodiphenylsilanediolate. These are the first regular polysiloxanes that contain both Si−H and T groups. The polymers have been characterized by 1H, 13C, and 29Si NMR as well as by IR spectroscopy and elemental analysis. Their molecular weight distribution (Mw/Mn) has been determined by GPC versus monodisperse polystyrene standards. Mn has also been determined by 1H NMR end group analysis. The highly regular microstructures of these linear polysiloxanes has been determined by 29Si NMR spectroscopy. Every third siloxane unit in these polymers is a RSiO3/2 (T) group. Both copolymers contain reactive Si−H groups that ...