Synthesis and characteristics of polystyryl aluminium derivatives and their reaction with benzoyl peroxide

Thermal polymerization of styrene in the presence of AlEt₃ acting as the chain transfer agent permits the synthesis of polystyryl derivatives of aluminium (polySt) _nAlEt_3?n(poly St-Al). It is possible to regulate the length of the polymer radical over a wide range (P_n = 2–800) by altering the ratio of the monomer to the chain transfer agent. A high degree of substitution of ethyl groups occurs only for styryl derivatives containing relatively low-molecular weight substituents (P_n = 2?30). The reaction of polySt-Al with benzoyl peroxide occurs virtually instantaneously even at 0° and is accompanied by the formation of free polystyryl radicals. Their continuous formation was regulated by introducing catalytic amounts of pyridine as the electron donor into the reaction mixture. A polySt-Al (P_n = 30)BPPy system was used as an example of showing that these systems can be very effective initiators of the low-temperature free-radical polymerization of a series of acrylic and methacrylic monomers. The process yields a block copolymer. The data was used for the further development of the synthesis of block copolymers with initiating systems of the poly StAl-peroxide type under low-temperature free-radical polymerization conditions.