The effect of different initiators and solvents on the title polymerization was studied．An isotactic crystalline polymer with melting range 183—193° was obtained when t-butyl acrylate was polymerized at room temperature with LiAlH4 or NaH as anionic initiator in hexane or toluene as solvent．When tetrahydrofuran (THF) was used as solvent

an amorphous polymer with softening range of 75°一90°was obtained．NaBH4 in hexane or toluene would not initiate the polymerization unless pyridine or THF was used as solvent，but an amorphous polymer was the product．For the hydride of alkali metal or its complex initiated anionic polymerization of the title vinyl monomer，the mechanism of hydride transfer to β-carbon atom of the monomer molecule was proposed．