Methyl methacrylate butyl lithium polymerized

This technique allows the formation of many different types of block copolymers. Lithium metal can be used to initiate polymerizations in solvents of varying polarity. Monomers, like styrene, a-methylstyrene, methyl methacrylate, butyl methacrylate, 2-vinylpyridine, 4 vinylpyridine, acrylonitrile, or methyl acrylate, can be used. The mechanism of initiation depends upon the formation of ion radicals through reactions of lithium with the double bonds ... 

There are some indications that the situation described above has been realized, at least partially, in the system styrene-methyl methacrylate polymerized by metallic lithium.29 29b It is known51 that in a 50-50 mixture of styrene and methyl methacrylate radical polymerization yields a product of approximately the same composition as the feed. On the other hand, a product containing only a few per cent of styrene is formed in a polymerization proceeding by an anionic mechanism. Since the polymer obtained in the 50-50 mixture of styrene and methyl methacrylate polymerized with metallic lithium had apparently an intermediate composition, it has been suggested that this is a block polymer obtained in a reaction discussed above. Further evidence favoring this mechanism is provided by the fact that under identical conditions only pure poly-methyl methacrylate is formed if the polymerization is initiated by butyl lithium and not by lithium dispersion. This proves that incorporation of styrene is due to a different initiation and not propagation. 

As a rule, the aggregation of lithium ester enolates is mainly governed by concentration, temperature and structure of the ester group. There is thus no reason for the polymerization of methyl methacrylate and f-butyl methacrylate to be influenced by the same experimental parameters. 

Living anionic polymerization of 4-vinylphenol was performed after transformation of the phenolic hydroxy group into trialkybilyl ether group and removal of the protection group after polymerization [125]. n-Butyl lithium was used for the synthesis of poly[2-hydroxy-4-methacryloyloxybenzophenone] [61] (102) or HALS terminated poly(methyl methacrylate) [126]. 2-Hydroxy-4-methacryloyl-... 

Schlaad, H., Muller, A. H. E., Kolshom, H., and Kruger, R.-P., Mechanism of Anionic Polymerization of (Meth)acrylates in the Presence of Aluminium Alkyls. 3. MALDI-TOF-MS Study on the Vinyl Ketone Formation in the Initiation Step of Methyl Methacrylate with ferf-Butyl Lithium, Polymer Bull., 35, 177, 1995. 

Some abnormalities were reported in the initiations of methyl methacrylate polymerizations in toluene by butyllithium. Their nature is such that they suggest the possibility of more than one reaction taking place simultaneously. One, which must be the major one, is that of the oiganomet-allic compound reacting with the carbon-to-carbon double bond as shown above. The other, minor one, may be with the carbon-to-oxygen double bond. The major reaction produces methyl methacrylate anions. The minor reaction, however, yields butyl isopropenyl ketone with an accompanying formation of lithium methoxide ... 

Table 18-5. Influence of the Polarity of the Medium on the Triad Fraction of Poly (methyl methacrylate) Polymerized at —30° C by Butyl Lithium...

The polymerization of acrylate esters by organomagnesium reagents is best described as pseudo-anionic monomer is complexed to a magnesium atom covalently bonded to carbon. The anionic polymerization of methyl methacrylate in benzene yields the syndiotactic polymer when the initiator is an alkali metal complexed with 18-dicyclohexyl-6-crown. When a solution of methyl methacrylate in toluene is placed below a solution of butyl-lithium in the same solvent at —78 °C so as to avoid any mechanical mixing, the polymer obtained has a higher isotacticity than that observed if the solutions are stirred. ... 

Baskaran, D. and Sivaram, S. (1997) Specific salt effect of lithium perchlorate in living anionic polymerization of methyl methacrylate and tert-butyl acrylate. Macromolecules, 30,1550-1555. 

The adducts of either butyllithium with DPE (1,1-diphenylhexyllithium) or polymeric organolithiums with DPE are the preferred initiators for polymerization of a wide variety of alkyl methacrylates and (ert-butyl acrylate [3]. For example, Stiihn and coworkers [77] recently reported the synthesis of well-defined, narrow molecular weight distribution polymers from methyl, ethyl, n-propyl, -butyl, n-pentyl, and n-hexyl methacrylates using the adduct of scc-butyllithium and DPE as initiator in THF at -78 °C in the presence of lithium chloride. This initiator was also used recently to copolymerize 2-tri-methylsiloxyethyl methacrylate and butyl methacrylate using analogous reaction procedures [78]. 

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