POLYMERIZATION OF ACRYLATES AND METHACRYLATES TO MAKE HOMOPOLMERS AND BLOCK COPOLYMERS INITIATED BY N-ALKOXYPHTHALIMIDES AND SUCCINIMIDES

摘要

Various N-alkoxyphthalimides were prepared and tested as initiators for polymerization of a variety of monomers. Acrylates and methacrylates polymerized at 40-50℃. Vinyl acetate and styrene were moderately reactive at 60-65℃. Rates of reaction were sensitive to the choice of solvent. THF generally gave the highest conversions, with much reduced reactivities in solvents of higher polarity, such as acetonitrile, acetone, DMSO or DMF. In aliphatic hydrocarbon solvents or di-n-butyl ether no polymers were obtained. Bulk polymerizations proceeded well, depending on the monomer. Rates of polymerization were sensitive to the structure of the group attached to nitrogen. OR groups, where R contained α-electron-withdrawing esters, benzylic or allylic groups, were more reactive than when R was an aliphatic group. A-B block copolymers were readily prepared, starting with PMA, PBA or PMMA. However, because the rates of initiation were slow, relative to rates of propagation, N-alkoxyphthalimide initiators survived mostly intact. Consequently, final A-B block copolymers were invariably contaminated with indeterminate amounts of homopolymer from polymerization of the second monomer.