GROUP TRANSFER AND CATIONIC POLYMERIZATION OF 1-BUTADIENYLOXYTRIMETHYLSILANE

As requirement for the synthesis of new C4-type periodic polymers, group transfer polymerization of 1-butadienyloxytrimethylsilane (BdTMS) was examined. Equimolar benzaldehyde (BAld)-ZnCl2 catalysts in benzene at 20°C were effective to give a soluble polymer in organic solvents. The structure of the polymer was revealed by NMR and IR analyses as 1,4-trans addition mode of diene. Dispersities (Mw/Mn) of molecular weight distribution evaluated by GPC reduced to about 1.5, clearly differing from about 3 in the case of ZnCl2 alone. SnCl4 or (C2H5)3Al2Cl3 without BAld polymerized BdTMS rapidly, accompanying gelation even at -78°C. Living propagation in BdTMS/BAld/ZnCl2 system was confirmed by the incremental monomer addition method. In NMR-monitoring the equimolar reaction of BdTMS/BAld catalyzed by ZnCl2 in C6D6, it was found that an aldol adduct appeared at the first stage and then a formyl group regenerated in the adduct began to react with the monomer.