Triethyl aluminum methacrylate monomer

The alkyl methacrylate monomers were available from various sources. Isobutyl methacrylate (IBMA) (Rohm and Haas) and t-butyl methacrylate (TBMA) (Rohm Tech) may be purified first by distillation from CaH, followed by distillation from trialkyl aluminum reagents as described in detail earlier (20,21). In particular, t-butyl methacrylate (b.pt. 150°C) was successfully purified by distillation, from triethyl aluminum containing small amounts of diisobutyl aluminum hydride. The trialkyl aluminum and dialkyl aluminum hydride reagents were obtained from the Ethyl Corporation as 25 weight percent solutions in hexane. The initiator, -butyllithium, was obtained from the Lithco Division of FMC, and analyzed by the Gilman "double titration" (22). 

The polymerizations of methyl methacrylate and methyl acrylate in the presence of triethyl aluminum are photochemical. The initiator forms a complex with the monomer which absorbs light at 400 mfi. The polymerzaition shows different behaviour from normal stationary radical polymerization. Firstly, the decay of polymerization after extinction of illumination is much slower than the decay theoretically expected for normal radical polymerization. 

In 1994, Finkelmann and coworkers [83] first reported LC-coil block copolymers with anionic polymerization of mesogenic methacrylates (see Scheme 7 E). However, monomer purification was a problem due to the crystalline nature of the mesogenic monomer. Finkelmann et al. used triethyl aluminum as an in-situ drying agent for successful anionic polymerization to obtain block copolymers with high molecular weights and narrow polydispersity... 

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